TW510143B - Method for deriving at least three audio signals from two input audio signals - Google Patents

Abstract

Various equivalent adaptive audio matrix arrangements are disclosed, each of which includes a feedback-derived control system that automatically causes the cancellation of undesired matrix crosstalk components in the matrix output. Each adaptive audio matrix arrangement includes a passive matrix that produces a pair of passive matrix signals in response to two input signals. A feedback-derived control system operates on each pair of passive matrix signals, urging the magnitudes of pairs of intermediate signals toward equality. Each control system includes variable gain elements and a feedback and comparison arrangement generating a pair of control signals for controlling the variable gain elements. Additional control signals may be derived from the two pairs of control signals for use in obtaining more than four output signals from the adaptive matrix.

Description

510143 A7 B7 V. Description of the invention (1) The present invention deals with an audio signal processing technology. In detail, the present invention relates to a "multi-directional" (or ,, multi-channel) audio decoding technology, which uses an adaptive matrix (or "active") audio matrix, which can Input the signal stream (or "signal" or "channel"), and export three or more audio signal streams (or, "5 signal" or "channel"). The present invention is used for audio signal recovery, in which each signal is associated with a direction, and is incorporated into a small number of signals by a coding matrix. Although the present invention is based on a well-designed signal coding technology in the description, it should be understood that the present invention does not need to use any specific signal coding technology, and is also used for two-channel reproducibility since the original. The recorded material produces some pleasing directional effects. BACKGROUND OF THE INVENTION An audio matrix encoding and decoding technique is well known in its prior art. For example, in a so-called ', 4-2-4 ,, audio matrix encoding and decoding technology, four source signals are usually related to four basic directions (such as, 15 for example, left, center, right and Four weeks, or left front, right front, left rear, and right rear) are associated with the amplitude-phase matrix and are encoded into two signals. The last two signals will be transmitted or stored and then decoded by an amplitude-phase matrix decoder to restore the approximate values of the original four source signals. This specially decoded signal is an approximate value, and their matrix decoders will suffer from the common disadvantages of crosstalk between their decoded audio signals. Ideally, the signals they decode should be the same as their source signals, and there is an indefinite interval between them. However, the inherent crosstalk in their matrix decoders usually results in a 3dB interval only between the signals associated with their adjacent directions. An audio matrix in which the matrix characteristics have not changed. In this 4 ^ paper size, the Chinese National Standard (CNS) A4 specification (210 X 297 mm) is applied ^ ':-_iaalav am · a · »· a ··· αχιίι II · a ··· »nn ϋ nnmnl Meal alv · nni 1_ · nnn I f Read first > i Matters before filling in this page)

Bureau of Economics and Property, Ministry of Economic Affairs-Printed by Employee Consumer Cooperative A7

V. Description of the Invention () 2 The technique is named "Passive," a matrix. In order to overcome the crosstalk problem in these matrix decoders, in their pre-existing techniques, 'known' is to appropriately change the characteristics of their decoding matrices in order to improve the interval between their decoded signals and to approximate them more closely. Their source is 5 ^. A well-known example of this active matrix decoder is Dolby Pr0.

The Logic decoder is described in U.S. Patent No. 4,799,260, which is incorporated herein by reference in its entirety. Therefore, the 26 patent cited some of its pre-existing technologies, many of which described a variety of other X-membered adaptive matrix decoders. Other pre-existing patents include 10 patents of the inventor, including U.S. Patent Nos. 5,625,696; 5,644,640; 5,504,819; 5,428,687, and 5,172,415. Each of these patents is incorporated herein by reference in its entirety. Although their pre-existing technology-type adaptive matrix decoders are intended to reduce crosstalk in these reproduced signals and to replicate their source signals more closely, the pre-existing technology described above is in some cases The 7C method in the method is that many of them are complicated and cumbersome, so that it is impossible to understand the favorable relationship between the intermediate signals in the decoders that can be used to simplify them and improve the accuracy of them. Therefore, the present invention is directed to some methods and devices, and they can understand and use the intermediate signals in these adaptive signal decoders to date which have not yet been understood. The use of these relationships allows their unwanted crosstalk components to be easily offset, especially using their automatic self-offset arrangements using negative feedback. Summary of the invention _______ 5 This paper size applies to China National Standard (CNS) A4 (21 × l97) 510143

V. Description of the invention (3) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs (please read the notes on the back before filling out this page) According to the first feature of the present invention, the present invention constitutes one that can be derived from two input audio signals Methods for at least three audio output signals, of which there are four audio signals 'borrow-passive matrix' derived from the last two input audio signals. The passive matrix can respond to two audio signals and generate two pairs of audio signals. No. one represents the first pair of derived audio signals (such as left and right signals) in a direction above a first axis, and one represents a second pair of directions in a direction above a second axis The first and second axes of the derived audio signals (such as "lingxin ,, and, and all around" signals) are generally perpendicular to each other. The mother-paired derived audio signals are processed to Generate their corresponding 10 first and second pairs of intermediate audio signals (left / right and center / peripheral pairs respectively) so that the relative amplitude of the audio signals in each pair of intermediate audio signals is large , Is pushed to equal the f-th output signal (such as the one above) in the first direction above the axis of the derived audio signal pair (left / right pair) produced by the first pair of middle signals (left / right pair). The left output signal L0u〇 is at least 15 by the same polarity, which is generated by combining at least one component of each second pair of intermediate audio signals (center / peripheral pair). One represents a signal located in the first pair of intermediate signals ( Left / right pair) The second output signal (such as the above-mentioned left output signal Rota) in the second direction above the axis of the derived audio signal pair (left / right pair) is generated by at least the opposite polarity. A combination of at least one component of the second pair of intermediate audio signals (20 center / four pairs). One represents a derived audio signal pair (left / right pair) generated by the second pair of intermediate signals (center / four pairs). The third output signal in the first direction above the axis (such as the above-mentioned center output signal cout or surrounding output signal sout) is to make each first pair of intermediate audio signals (by at least the same polarity or opposite polarity) ( Left / right This paper size applies to the Chinese National Standard (CNS) A4 (210 X 297 mm) 510143 A7 B7 V. Description of the invention () 4 10 15 The property bureau of the Ministry of Economic Affairs * prints 20 pairs of employee consumer cooperatives) Optionally, one represents a fourth output signal (such as the above-mentioned one) located in the second direction above the sleeve line of the derived audio signal pair (middle four) generated by the second pair of intermediate signals (center / fourth). If the third output signal is the above-mentioned center output signal (: _, or the above cout, if the above-mentioned third output k is Sout), 'if the above-mentioned third output signal When it is generated with the same polarity, it will use the opposite polarity, or if the third output signal above is generated with the opposite polarity, it will use the same polarity to combine at least each first pair of intermediate audio signals (left / Right pair). The relationship between their decoded signals to date has not been understood is that by pushing the size of the intermediate audio signals in each pair of intermediate audio signals to be equal, the undesired crosstalk components in their decoded output signals will generally be Will be suppressed-. In order to achieve a substantial crosstalk cancellation, the principles need not be exactly equal. This processing technique can be realized immediately and better by using the negative feedback arrangement which can function to automatically cancel the undesired crosstalk components. The invention includes embodiments having an equal topology distribution. In each embodiment, as described above, their intermediate signals are derived from a passive matrix operating on a pair of input signals, and the intermediate signals are pushed to equality. In their embodiment with a first topology, the offset components of their intermediate signals are combined with their passive matrix signals (from the above-mentioned input signals or other passive matrices that operate on them). 'To generate their output signals. In an embodiment using a second topology, their paired intermediate signals are combined with their output signals. 0 This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm). ------------- Agriculture -------- Order------------- (Please read the notes on the back before filling this page) 510143 A7

5. Description of the invention (5) Other features of the present invention include the derivation of additional control signals which can be used to generate some additional output signals. (Please read the notes on the back before filling this page) One of the main purposes of the present invention is to perform clear and significantly high-level crosstalk cancellation under a wide range of input signal conditions. Electronic circuits with specific requirements related to accuracy, and no need for unusual complexity in the aforementioned control paths, both of which were found first in the art. In another aspect of the present invention, such high performance can be achieved by using a simpler or lower cost electronic circuit than the prior art circuit. 10 Brief description of the diagram. Figure 1 is a functional and schematic diagram of a passive decoding matrix that is helpful to understand the pre-existing technology of the present invention. Figure 2 is a diagram that helps to understand the pre-existing technology of the present invention. A functional and schematic diagram of a passive decoding matrix. Among them, a passive signal output of a variable scale version 15 is in their linear combiner and is added to their unchanged passive matrix output; Printed by the Ministry of Intellectual Property Bureau, Consumer Cooperative, Figure 3 is a functional and schematic diagram of the feedback-derived control system made according to the present invention, which is the left and right vc A and the sum and difference of Figure 2 VC A, and vc a in other embodiments of the present invention; 20 FIG. 4 is a functional and unintended diagram showing an arrangement made according to the present invention equal to the combination of FIG. 2 and FIG. 3, where The output combination is in response to the above-mentioned Lt and Rt input signals, and generates these passive matrix output signal components' instead of receiving the passive matrix used to derive their offset components from above; 8 This paper standard applies Chinese national standards ( CNS) A4 specifications 210 X 297 mm) Printed by the Bureau of Intellectual Property, Ministry of Economic Affairs, X Consumer Printing Co., Ltd. 510143 A7 __B7 __ V. Description of the invention () 6 Figure 5 is a diagram showing a system made according to the present invention which is equal to Figures 2 and 3. The functional and schematic diagrams of the arrangement combined with Figure 4, in the configuration of Figure 5, they must maintain equal signals, the signals they apply to the above-mentioned output derivation coupler, and the above The signals that can control the feedback circuit of VCA; 5 The output of their feedback circuit, including their passive matrix components; Figure 6 is a display that shows an equivalent to Figures 2 and 3 according to the present invention. The functional and schematic diagrams of the combined arrangement of Figure 4 and Figure 5, where a VC A and the variable-gain-circuit gain (1-g) provided by the subtractor are replaced by a VCA, Its gain changes in the opposite direction of the VCA of 10 in the configuration of the VCA and the subtractor described above. In this embodiment, their passive matrix components are implicit. In other embodiments, their passive matrix components are exposed; Figure 7 is a plot of the left and right VCA gains gi and gr (vertical axis) of the Lt / Rt feedback-derived control system described above. The idealized curve of the above-mentioned disk rotation angle α (horizontal 15 axis); FIG. 8 is a graph which can draw the sum of the above Lt / Rt feedback-derived control system and the difference VCA gain gd〇gs (vertical axis) The idealized curve of the above-mentioned disk rotation angle α (horizontal axis); FIG. 9 is a left / right where the maximum and minimum values of the control signal can be plotted according to the scaling of +/- 15 volts, The idealized curve of the sum / difference control voltage (vertical axis) and their opposite phase rotation angles α (horizontal axis) with their opposite phases; Figure 10 is the smaller one that can draw the curve in Figure 9 (The straight and straight paper size of this paper applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm)) ----------- ^ 一 --------- Order ---- I I ---- * 5 ^ (Please read the notes on the back before filling this page) 510143 A7 B7 V. Description of Invention () 7 10 15 Printed by the Consumer Cooperative of Intellectual Property Bureau of the Ministry of Economic Affairs Line) The idealized curve of the above-mentioned disk rotation angle α (horizontal axis); Figure 11 is a smaller one (straight straight axis) that can draw the curve in Figure 9 to the above-mentioned disk rotation angle, ( (Horizontal axis) idealized curve, which is related to the case where they and the differential voltage are scaled by 0.8 before the smaller one of the above curves is used; Figure 12 is a picture of the above left-to-back / Right-back feedback-derived control system idealized curve diagram of the left and right back VCA gains gib and grb (vertical axis) to the above-mentioned disk rotation angle α (horizontal axis); Figure 13 is based on this Functionality and schematic diagrams of an active matrix decoder that can get six outputs for a part of the invention; Figure 14 is a six-round active matrix that can be used for a person similar to Figure 13 The derived functional and schematic diagrams of the six cancellation signals in the decoder, and the 15th and .15A-P diagrams are schematic circuit diagrams that can show an actual circuit with the features of the present invention. Detailed description of the preferred embodiment A passive decoding matrix is shown functionally and schematically in Figure 1. The following equations deal with the relationship between their inputs, 1 ^ and Rt (, · total left, and total right π) and output: •-. £ --- L · I ---- install -------— Order --------— (Please read the notes on the back before filling in the page) 20 L〇ut ~ LtR〇ut = Rt Cout = l / 2 * (Lt + Rt) S〇ut-(In these and other equations (Equation 1) (Equation 2) (Equation 3) (Equation 4) ^ Symbols throughout the document are 10 paper sizes applicable to Chinese National Standard (CNS) A4 Specifications (210 X 297 mm) 510143 A7 B7 V. Description of the invention () 8 • Printed by the Ministry of Economic Affairs and Intellectual Property Consumers Cooperatives to indicate the multiplication of the above-mentioned central output, which is the sum of their inputs, and the above-mentioned four-week output ' The difference between the inputs. The two have another scaling factor; this scaling factor is arbitrary, and for ease of interpretation, it is selected as 1/2. Other scaling factor values are possible. The above C () ut output 'is obtained by applying them] and Rt with a scaling factor of +1/2 to a linear combiner 2. The above Sout output is obtained by dividing them1 ^ and Rt with a scaling factor of +1 / 2 and -1 / 2 are obtained by applying a linear combination of 4. The passive matrix in Fig. 1 can generate two pairs of audio signals; the first pair Are Bieyi and Rout, and the second pair is Couju Sout. In this example, the basic output direction of the above passive matrix is specified as " left ", ,, center π," right ",:., And f • around ". Their adjacent basic output directions are above their mutually perpendicular axes, so that for the marking of these directions, their left is adjacent to their center and surroundings; their surroundings are to their left and right. Adjacent, etc. It should be understood that the present invention can be applied to any orthogonal 2: 4 decoding matrix. A passive matrix decoder can derive n audio signals from m audio signals, where, according to A constant relationship (for example, 20 in Fig. 13, 〇_ is always 1/2 * (Roout + Lout)), η is greater than m. In contrast, an active matrix decoder, Based on a variable relationship, η audio signals are derived. A configuration of an active matrix decoder The method is to combine their signals and dependent signal components with the output signals of a passive matrix. For example, as shown in Figure 2 functionally and schematically, their four can be used 10 15 ------------- Installation ------- Order --------- Line (Please read the precautions on the back before filling this page) 11 Paper Size Applicable to China National Standard (CNS) A4 (210 X 297 mm) 510143

Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs V. Invention Description (9) VCA (Voltage-Control Amplifier) 6, 8, 10, and 12 to deliver some variable-scale versions of passive matrix outputs In the linear couplers 14, 16, 18-, and 20, they are added to their unchanged passive matrix outputs (that is, the upper two inputs themselves and the two outputs of their couplers 2 and 4). The inputs of 泫 a and vc A are derived from the left, right,, center, and surrounding outputs of the passive matrix mentioned above, and their gains can be specified as gl, gr, gc, and gs (all are positive ones) VCA output signals are composed of their cancellation signals and are combined with their passively derived outputs, the latter having a crosstalk from the direction from which their cancellation signals are derived, 10 by suppressing the crosstalk To enhance the directional performance of the above matrix decoder. It should be noted that in the arrangement of Figure 14, the path of the above passive matrix still exists. Each output is the above corresponding passive matrix output plus two VCAs. Output combinations. VCA output is to consider that their crosstalk components are born in their output representing adjacent basic output directions. 15 are selected and scaled in order to provide the above-mentioned hope for their corresponding passive matrix output. Crosstalk cancellation. For example, a center signal has crosstalk in the left and right signals of their passive decoding, and a four-way signal has a crosstalk in the left and right signals of their passive decoding. Therefore, the above-mentioned left signal output should be combined with the offset signal components derived from the center of these passive decoding and around 20 signals, as well as the other four outputs. Their signals are shown in Figure 2. The scaling, polarization, and combination methods will provide the above-mentioned desired crosstalk suppression capabilities. By changing their correspondence within the range of zero to 1 (for the scaling example in Figure 2) The gain of VCA, the undesired crosstalk in the output of these passive decoding becomes 12 This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ί I ^ ---- r ---- Install -------- Order --------- ^ _ w < Please (Please read the notes on the back before filling this page) 510143 A7 V. Description of Invention () 10 10 15 Ministry of Finance, Intellectual Property Office, Employees Consumer Cooperatives Co., Ltd. 20 copies will be suppressed. The arrangement in Figure 2 has the following equation: L〇ut = LtSgc * i / 2 * (Lt4.Rl) .gs * i / 2 * (Lt.Rt) R〇ut = Rt ^ gcM / 2 * (Lt + Rt) + gs * l / 2 * (Lt-Rt) C〇ut = l / 2 * (Lt + Rt) .gIM / 2 * Lt-gr * l / 2 * Rt S〇ut = l / 2 * ( Lt-Rt) .gI * i / 2 * Lt + gr * l / 2 * Rt If all VC A series have zero gain, the above arrangement will be the same as their passive matrix. For all VCA gains of any equal value, the arrangement of Figure 2 is the same as the passive matrix described above, except for a fixed scale. For example, if all VCA systems have a gain of 0 ″: L〇ur ~ Lt-0.05 * l / 2 * (Lt + Rt) -0.05 * l / 2 * (Lt-Rt) = 0.9 * LtR〇ia = Rt-0.05 * l / 2 * (Lt + Rt) + 0.05 * l / 2 * (LrRt) = 0.9 * Rt Cout = l / 2 * (Lt + Rt) -0.05 * l / 2 * Lr0.05 * l /2*Rt=0.9*l/2*(L t + Rt) " ji-Sout = l / 2 * (LrRtH) .05 * l / 2 * Lt + 0.05 * l / 2 * Rt = 0.9 * l / 2 * (LrRt) The above result is the above-mentioned passive matrix scaled by a factor of 10 · 9. Therefore, it is clear that the precise value of the static VCA gain described below is not important. Consider an example, only in terms of their basic output directions (left, right, center, and surrounding), their corresponding inputs are only Lt, only Rt, and L have the same polarity), and Lt = -Rt (opposite polarity ), And their corresponding hope that the output is only Lout 'only R. ^, Only cout, and only Sout. In each case, ideally, one output should deliver only one signal, and the remainder should deliver without signals. (Equation 5) (Equation 6) (Equation 7) (Equation 8)

Rt (of · II (please read the precautions on the back before filling this page); line · 13 This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) A7 V. Description of invention () 11 10 15 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. It is clear that if these VCAs can be controlled so that the one corresponding to the basic output direction of the above hope has a gain, and the remainder is very low. Below 1, all outputs except those mentioned above, their VCAf signals will cancel their undesired outputs. As explained above, in the configuration in Figure 2, their VCA outputs are at In effect, it can offset the crosstalk components in their adjacent basic output directions (where the above-mentioned passive matrix has crosstalk). So 'for example, if the two inputs are fed with equal in-phase signals 'So that Rt = Lt = (for example) !, and as a result, gc == i, and ❾, gr, and gs are all zero or close to zero, we get: Lout = ll * l / 2 * ( l + l) -〇 * i / 2 * (i)) = 〇R〇ut = ll * l / 2 * (l + l) + 〇 * i / 2 * (i .i) = 〇C〇ut =? l / 2 * (l + i) .〇 * i / 2 * i-0 * l / 2 * l = l S〇ut == i / 2 * (l -l ) .〇 * 1/2 * 1 + 0 * i / 2 * l = 〇 Its only output is from the above hoped C () ut. A similar calculation will show that the same result is applicable to one from only The situation of signals in one of the other three basic output directions. Their equations 5, 6, 7, and 8 can also be written as follows: L〇ut f ^ I ill ---- ^ -------- -(Please read the notes on the back before filling this page) 20 l / 2 * (Lt + Rt) * (l-ge) + 1/2 * (LrRt) * (i.gs) (Equation 9) C〇 ut = l / 2 * Lt * (lg,) + l / 2 * Rt * (l.gr) R〇ut = l / 2 * (Lt + Rt) * (l-gc) -l / 2 * (LrRt ) * (l-gs) S〇ut = l / 2 * Lt * (l.gl) -l / 2 * Rt * (l-gr) (Equation 10) (Equation 11) (Equation 12) Arrange here Each output is the combination of two signals, Loudor Rout, and 'both refer to the sum and difference of the above input signals, and their sum and 14 510143 Α7

V. Description of the invention () 12 15 II A printed by the Ministry of Economic Affairs, Intellectual Property, Employees, and Consumer Cooperatives (the output of the ACA is 20) (the input of the search is VCA derived from the above center and surrounding directions, and these directions are related to their left and right directions) Phase vertical). Both cout and Sout are related to their actual input signals and their left and right VCA gains (their corresponding inputs are 5 VC A derived from these left and right directions, such directions Pairs are perpendicular to their center and surroundings). Consider a non-basic direction, where Rt is fed with the same signal as above, which has the same polarity but undergoes attenuation. This condition means that a signal is somewhere between their left and center basic output directions, and therefore they should deliver their output from Lout * coout with little or no output from RodoSout . As far as R_ and Sout are concerned, this zero output can be completed when the above two items are of equal size but opposite polarity. As far as Rout is concerned, the relationship between this offset is [l / 2 * (Lt + Rt) * (l-ge)] = [l / 2 * (Lt-Rt) * (l-gs)] Magnitude (Equation 13) As far as Sout is concerned, the relationship between this offset is the magnitude of [l / 2 * Lt * (lg 丨)] = the magnitude of [l / 2 * Rt * (Bu gr)] (equation 14) Considering a signal turning (or just located) in one of the signals between any two adjacent basic directions, the same relationship between the last two will be revealed. In other words, when the above input signals represent sounds transferred between any two adjacent outputs, these magnitude relationships will ensure that the above sounds appear from the above-mentioned outputs corresponding to their two adjacent basic directions. , And the other two outputs do not deliver signals. In order to achieve this result in general, the paper size of the above two papers within 34.37 of each party applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) ------------- ^ -------- ^ --------- ^ (Please read the precautions on the back before filling out this page) 510143 A7 V. Description of Invention () 13 10 15 Employees ’Consumption of Intellectual Property, Ministry of Economic Affairs The size of the 20 items printed by the cooperative should be pushed to equal. This can be accomplished by seeking to keep the relative sizes of the two pairs of signals in the above-mentioned initiative matrix equal: [(Lt + Rt) * (l-ge)]-[(LrRt) (l-gs)] Big + (Equation 15) and the size of [Lt * (l-gl)] = [Rtm)] (Equation 16) The desired relationship shown in Equations 15 and 16 is related to their Equations 13 and The 14 are the same, but their scaling is omitted. Their combined polarities and their scaling can be taken into account when the corresponding outputs above are obtained using couplers Η, 16, 18, and 20 in Figure 2. The present invention is based on the discovery of these equal amplitude magnitude relationships that have not been known to date, and preferably as explained below, based on the use of self-acting feedback control to maintain these relationships. From the above discussion of the cancellation of unwanted crosstalk signal components and their requirements related to their basic output directions, it can be deduced that, in terms of the scaling used in this interpretation, the maximum gain of a VCA should be! . Under static, undefined, or "uncontrolled" conditions, their VC As should use a small gain to effectively provide the passive matrix described above. When the gain of one of a pair of VCAs is required, When the static value rises toward 1, the other of the pair can be kept at the static gain described above, or can be moved in the opposite direction. A convenient and practical relationship is to keep the product of the gain of the pair as a constant .Using their analog VCA, their gain in dB is a linear function of one of their control voltages. This is a control voltage that is equal to 16 paper sizes. Applicable to China National Standard (CNS) A4 (210 X 297). Mm) _— ^ --- h ------ · install ------- order · --------- (Please read the precautions on the back before filling this page) 510143 A7 B7 V. Description of the Invention (14) The ground (but with valid opposite polarity) will automatically occur when it is applied to both of the above two pairs. Another alternative is to keep the sum of the gains of the above pairs to a constant. Of course The invention can be realized digitally or in software, rather than using their analog components. 5 So, for example, if the above-mentioned static gain is 1 / a, an actual relationship between the above two gains may be the product of them, so that gi * gr = l / a2, and gc * gs = l / a2, a typical value for 7 ', may be in the range of ι0 to 20. 10 Figure 3 shows functionally and schematically, the left and right VCAs of Figure 2 (6 and 12 respectively) A related feedback-derived control system. It can receive the above-mentioned Lja 1 input signals, can process them to derive their intermediate LJCl-gO and Rt * (l-gr) signals, and can compare their intermediate signals. Size, and can respond to any difference in the size of each other to generate an error signal. 15 This error signal allows their VCA to reduce the difference in their size. One way to accomplish this is to rectify their intermediate Signals to derive their magnitudes, and apply these two magnitude signals to a comparator, and their output 'can control the gain of their VCAs and make them polar, for example, can make the above Lt signal The increase within can increase g | and decrease gr by 20. Their circuits The value (or their digital equivalent or equivalent in software manifestation) is selected such that when the output of the comparator is zero, the gain of the static amplifier is less than 1 (for example, 1 / a). In the above analog domain, a way to actually realize the above comparison function is to convert the above two sizes into the above log domain, so that the above comparator 17 paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297) Li) I ------------ install --- (Please read the precautions on the back before filling out this page) Order--Reference-Printed by the Ministry of Economic Affairs, Intellectual Property, Employees, Cooperatives, and Consumers 510143 Printed by the Consumers' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 V. Invention Description (15) They can be subtracted instead of determining their scale. Many analog VCAs have gains that are proportional to an exponent of one of the control signals described above, so that they can naturally and conveniently use the anti-values of the control output of the log-based comparator described above. However, in contrast, if it is realized digitally, it can more conveniently divide the above two sizes, and use the result as a direct multiple or divisor of their VCA function.

In detail, as shown in Fig. 3, the above 1 ^ input is applied to their "left" VCA 6 and an input to a linear coupler 22 having a + ι scale. The output of the above left VC A 6 is applied to the above-mentioned combiner 22 with a scaling ratio of 10 to 1 (thus forming a subtractor), and the output of the above-mentioned combiner 22 is applied to a full-wave rectifier 24. The above input is an input applied to the right VCA 12 described above, and a linear combination benefit 26 of a rabbit self-discharge ratio of +1. The output of the above right V C A 12 is applied to a combiner 26 with a scale of -1 (thus 15 forms a subtractor), and the output of the above combiner 26 is applied to a full wave rectifier 28. The outputs of these rectifiers 24 and 28 are applied to the non-inverting and inverting inputs of an operational amplifier 30, which operates as a differential amplifier, respectively. The output of the amplifier 30 can provide a control signal that is a daily error signal, which is applied to the gain control input 20 of the VCA 6 without inversion, and is applied to the gain of the VC A 12 with inverse polarity. Control input. The above error signals are two signals indicating that their sizes are to be equalized, which have different sizes. This error signal is used to control π their VCAs in the correct direction to reduce the difference in the magnitude of their intermediate signals. The output from the couplers 16 and 18 above is taken from Their VCA 18 This paper size is applicable to Chinese National Standard (CNS) A4 (210 X 297 mm) U—ί --------------------- (Please read the back first Note: Please fill in this page again.) 510143 A7 B7 V. Invention output () 16 6 and the output of VCA12. Therefore, each intermediate signal has only one component, which is applied to these output couplers, that is, -Ltgr and -Rtg |. As far as the conditions of their steady-state signals are concerned, the difference in magnitude above can be reduced to a negligible amount by providing sufficient loop gain. However, the crosstalk cancellation is generally completed for 5, It is not necessary to reduce the differences within their sizes to zero or a negligible amount. For example, a loop gain sufficient to reduce the above-mentioned dB difference by a factor of 10, theoretically in the worst case, Will incur better than 30 dB reduction in crosstalk. For their dynamic conditions, the above feedback control The time constants in the row should be selected to promote their equality in size, at least in terms of most of the signal conditions, basically making them inaudible. The details of the selection of their time constants are It is outside the scope of the present invention. Preferably, their circuit parameters are selected so as to provide a negative feedback of about 20dB, and thus the gain of their VCA cannot be increased above 1 15. For the examples of scaling shown in the description of the arrangements in Figures 14, 16, and 17, the gain of their VC A can change from a small value (for example, 1 / a2 is much less than 1), and the change rises to But it does not exceed 1. Due to the negative feedback mentioned above, the arrangement in Figure 3 will work to keep their signals entering the rectifiers nearly equal. 20 Because their correct gain is not important when they are very small, any Other relationships that can force one of the above pairs to gain a small value each time the other rises towards 1 will produce similar results that are acceptable. Center of Figure 2 and surrounding VCAs (8 and 10 respectively) Related feedback-derived control system As mentioned, it is generally the same as the arrangement in Figure 3. 19 paper sizes are applicable to the Chinese National Standard (CNS) A4 (210 X 297 mm) -------------- Loading ·-(Please read the precautions on the back before filling out this page) ιδΊ. • Printed by the Ministry of Economic Affairs, the Intellectual Property Association of Poor Employees, Consumer Cooperative 510143 A7

V. Description of the invention (17) But the received is not SLt * Rt, but their sum and difference, and they can be output from their VCA 6 and VCA 12 (which constitutes one of the components of the corresponding intermediate signal mentioned above) ' Applied to their couplers 14 and 20. Therefore, a high degree of crosstalk cancellation can be accomplished under a wide range of input 5 signal conditions, using some electronic circuits without specific requirements related to accuracy, and simultaneously using an integrated signal path Simple control path inside. The feedback / derivation control system described above can operate to process the audio signal pairs from the passive matrix mentioned above, so that the relative amplitude of the intermediate audio signal in each pair of intermediate audio signals will be pushed to 10 To be equal. The feedback-derived control system shown in Fig. J can reversely control the gains of the two VC A 6 and 12 so that the above-mentioned inputs to the rectifiers 24 and 28 are pushed in equal directions. These two items are pushed to the same degree depending on the characteristics of the rectifiers, the comparator 30 followed by them, and the gain / 15 control relationship of the VC As. The larger the loop-gain, the closer the above-mentioned equality is, but regardless of the characteristics of these components (of course, the condition is the polarity of their signals, which can reduce their level difference). will happen. In fact, the above comparator may not have infinite gain, but it can be implemented as a subtractor with limited gain. 20 If the rectifiers are linear, that is, if their output is directly proportional to the size of their input, the output of the comparator or subtractor will be a function of the difference in signal voltage or current. If it is replaced, the distant rectifiers respond to the logarithm of their input sizes, that is, in response to the above-mentioned level expressed in dB, one of the 20 paper sizes executed at the input of the comparator applies the Chinese National Standard (CNS) A4 Specifications (210 X 297 mm) Please read the lacquer on the back and save it in writing. Tr --------- Printed by the Consumers ’Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 510143 A7 B7 -Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 5. Description of the Invention () 18 Subtraction is the proportion of their input levels. The advantage is that its results will be irrelevant to the absolute signal level mentioned above, and only rely on the difference in dB of the above signal. Considering their source signal levels expressed in dB, they can more closely reflect human perception, which means that the other 5 events equal to the loop_gain are not related to loudness, and therefore the degree to which they are pushed to equal, is also It has nothing to do with absolute loudness. Of course, at a very low level, their logarithmic rectifiers will terminate the precise operation, and therefore there will be an input critical value, below which the termination of the above-mentioned pushes will be equal. However, the result is that its control can be maintained over the entire dB range of 70 or more without the need for a particularly high loop-gain of 10 high input signal levels, with the ultimate potential associated with the stability of the above-mentioned loop problem. Similarly, these VCAs and 12 may have gains (ie, multipliers or dividers) that are directly or inversely proportional to their control voltages. This may have the effect that when their gains are small, a small absolute change of 15 in the above control voltage may cause a large change in the above-mentioned gain expressed in dB. For example, consider a Vca with a maximum gain of 1, as required in the configuration of this feedback-derived control system, and a control voltage Ve that varies from, for example, 0 to 10 volts, so that the above-mentioned gain It can be expressed as A = 0.1 * VC. When Ve is close to its maximum value, a change from 100 mV (volts), for example, from 9900 to 20000 mV, will achieve a 20 * 100 g (10,000 / 9900). ) Or a gain change of about 0.09 dB. When v. Even at a small time, a 100 mv change from, for example, 100 to 200 mV, can achieve a gain change of 20 * i0g (200/100) or 6 dB. As a result, the above-mentioned effective loop-gain, and thus the response rate, will largely depend on whether the above-mentioned control signal is large or small, and this paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 public love) -------- ^ --------- ^ (Please read the notes on the back before filling out this page) 510143 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 ) 19 changes. Again, there may be issues related to the stability of the above circuits. This problem can be eliminated by using their VC A. The gain in dB of vc A is proportional to the above control voltage, or as shown in Table 5. The gain of their voltage or current is based on The exponent or antilog of the above control voltage depends on. Once the above-mentioned control voltage is within its range, a small change similar to 1000 mV in the above-mentioned control voltage will then bring about the same dB change in their gain. These devices can be immediately used as analog ICs, and their characteristic values or their approximate values will be easily completed in digital realization. This preferred embodiment uses logarithmic rectifiers and exponentially controlled variable gains. Amplification effect 'can deliver more close to the uniform push (considered in dB) over a wide range of their input levels and the ratio of the previous two input signals. 15 Because in human hearing, the perception of its direction is not constant with frequency, it wishes to apply certain frequencies weighted to the signals entering the rectifier 'in order to emphasize the frequencies that can best contribute to the human sense of direction, And failure to emphasize those controllers that may lead to improper control. Therefore, in their actual embodiments, the rectifiers 24 and 28 in FIG. 3 have a filter derived from their experiments before the collar to provide a filter that can attenuate their low and extremely high frequencies. Response, and can provide a gentle rising response in the middle of the entire audible range. It should be noted that these filters do not change the frequency response of their output signals, they only change their control signals and the VCA gains in their feedback-derived control systems. 22 This paper size is in accordance with China National Standard (CNS) A4 (210 X 297 mm). ^ 1 · ^ —----- tr -------- > ^ w (Please read the Please fill in this page again for attention) 510143 A7 B7 _ Μ Ministry of Economy, Wisdom and Property Bureau. Printed by the Consumer Consumption Cooperative. V. Invention Description () The arrangement of 201 and the combination of Figures 2 and 3 is functional and schematic. Sexually shown in Figure 4. It is different from the combination of Figures 2 and 3 in that their output combiners' can respond to their Lt and Rt input signals to generate the passive matrix output signal components, rather than the passive components derived from the offset components. Sex 5 matrix receives them. The above arrangement can provide them with the same results as the combination of Figures 2 and 3, provided that they have the same coefficients, which are basically the same as their passive matrix. Figure 4 is a combination of the feedback arrangements described in Figure 3. The “L” and Rt inputs of the “a” in FIG. 4 are first applied to 10 as in the passive matrix configuration in FIG. 1 and include the passive matrices of the couplers 2 and 4. The above is also the passive matrix "left", the Lt input of the output is applied to the above "left" VCA 32, and an input to a linear combiner 34 with a +1 scale. The above left VCA 32 The output is applied to a combiner 34 (thus forming a subtractor) with a scale of f-1. The above is also the passive input of the passive matrix " right " 'VCA 44, and an input to a linear combiner 46 with a +1 scale. The output of the above right VC A 44 is applied to the above-mentioned combiner 46 having a scale of -1 (thus forming a subtractor). The outputs of these combiners 34 and 46 are their signals Lt * (l-gl) * R, (l-gr) ', respectively, and they want to keep their magnitudes equal, or push them equal. To achieve this result, their signals are preferably applied to a feedback circuit as illustrated in and related to FIG. 3. These feedback circuits can then control the gain of their VC A 32 and 44. In addition, referring to Fig. 4, the above passive matrix from the combiner 15 20 23 The paper size applies to the Chinese National Standard (CNS) A4 specification (21 × x 297 mm--II--I--III i- --I--II II I--I-^ (Please read the notes on the back before filling in this page) 43 1Xο 5 A7 B7 Jade invention description) 21 10 15 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 20 The "center" output is applied to the above, the center "VCA 36", and an input to a linear combiner 38 with a +1 reduction ratio. The output of the above-mentioned central VCA is applied to the above-mentioned combiner 38 having a scaling ratio of -1 (thus forming a subtractor). The aforementioned 'peripheral' output from the passive matrix of the combiner 4 is applied to the aforementioned 'peripheral', VC A 40, and an input to a linear combiner 42 having a +1 scale. The output of the above-mentioned four yCA 40 is applied to the above-mentioned combiner 42 having a scale of -1 (thus forming a subtractor). The outputs' of these combiners 38 and 42 are the signals and l / 2 * (Lt-Rt) * (l-gs) respectively, and they hope to keep their signals equal in size or push them towards equal. To achieve this result, their signals are preferably applied to a feedback circuit as illustrated in and related to FIG. 3. These feedback circuits can then control the gains of these VCs 32 and 44. The output signals Lout, Cout, Sout, and Rout are generated by their couplers 48, 50, 52, and 54. Each combiner can receive the outputs of the two previous VCAs (these VC A outputs that make up a component of the intermediate signal whose size is sought to remain equal) to provide their input of the offset signal and either or both Signals in order to provide their passive matrix signal components. In detail, the above-mentioned input signal Lt is applied to the above-mentioned Lout coupler 48 at a scale of +1, and is applied to the above-mentioned CQui coupler 50 at a scale of +1/2. It is applied to the Sout coupler 52 described above at a scale of Ή / 2. The above-mentioned input signal Rt is applied to the above-mentioned R_combiner 54 with a scaling ratio of +1, and is applied to the above-mentioned C_combiner 50 with a scaling ratio of +1/2, and at a -1 / 2 scale, please read the notes on the back and front before applying it. Please fill in the direct installation. Page 1 w | IIIII% 24 This paper size is applicable to China National Standard (CNS) A4 (210 X 297 mm) ) M0143 A7

Printed by the Ministry of Economic Affairs ** Printed by the consumer cooperative of property employees V. Sout coupler 52 described in the invention description (22). The above-mentioned left VCA 32 output is applied to the above-mentioned (: coffee combiner 50, and also reduced to --1 / 2. The scaling ratio is not known to the above-mentioned Sout combination. Device 52. The above-mentioned right VC A 44 output is applied to the above-mentioned coup coupler 50 5 ′ at a scaling ratio of 7 ^ 1/2 and a +1/2 scaling ratio is applied to the above-mentioned S 〇ut combiner 52. The above < central VC A 3 6 output is applied to the above-mentioned L_combiner 48 at a scale of -1, and is applied to the above Rota union at a scale of -1. 54. The VC A 40 output of the four surroundings mentioned above is applied to the above-mentioned LQut combiner 48 at a scale of -1, and is applied to the above-mentioned Rout coupler 54 at a scale of +1. It should be noted For example, in Figures 2 and 4, for example, in Figures 2 and 4, these offset signals may initially appear, and they are not compatible with their passive matrix signals (for example, some offsets The signal is applied to the couplers with the same polarity as the passive matrix signal applied; however, at 15 Zhong 'When a cancellation signal becomes significant, it will have a polarity that is indeed opposite to that of the passive matrix signal of the temple. Another arrangement equal to the combination of Figures 2 and 3 and Figure 4 is functionally and Schematically shown in Figure 5. In the configuration of Figure 5, they are required to maintain a phase% * signal, which they apply to these output-derived couplers and to 20 of the above feedback to control VCA The signals of the circuit. These signals include their passive matrix output signal components. In contrast, in the arrangement in Figure 4, the signals applied by the self-feedback circuit to the above output coupler are their VCA outputs. Signals, and exclude their passive matrix components. Therefore, in Figure 4 (and in the combination of Figures 2 and 3), their passive matrices are composed of 25 paper standards applicable to the Chinese National Standard (CNS) A4 Specifications (210 X 297 mm) -------------- installation -------- order --------- line (Please read the precautions on the back first (Fill in this page again) 510143 A7 B7 V. Description of the invention () 23 10 15 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 20 copies Explicitly combined with the output of their feedback circuit, and in Figure 5, the output of their feedback circuit includes their passive matrix components' and their: themselves are sufficient. It will also be sufficient Note that in the arrangement of Figure 5, their intermediate signal outputs, rather than their VCA outputs (they each constitute only one of the components of the above intermediate signals), are applied to these output combiners. However The configurations of Figures 4 and 5 (plus the combination of Figures 2 and 3) are equal, and if their addition coefficients are accurate, their output from Figure 5 is the same as It is the same from Figure 4 (combined with Figures 2 and 3). In Figure 5+, their four intermediate signals in equations 9, 10, 11, and 12 are [l / 2 * (Lt + Rt) * (l-gc)], [l / 2 * (Lt -Rt) * (Ngs)], [l / 2 * Lt * (Ig |)], and [l / 2 * Rt * (l-gr)] are obtained by processing such passive matrix outputs, and Addition or subtraction is then performed to derive their desired output. These signals are also fed to the last two feedback circuits: the rectifier and the comparator of the circuit, as described above in Figure 3. These feedback circuits are best to keep their signal pairs equal in size. The feedback circuit in FIG. 3 is the same as the configuration applied in FIG. 5, so that the output from these output couplers can be taken from the outputs of their couplers 22 and 26 instead of from them. VC A 6 and 12 〇 Still referring to Figure 5, the connections between their couplers 2 and 4, VC A 32, 36, 40, and 44 and couplers 34, 3 8, 42, and 46 are connected to the first The arrangement in Figure 4 is the same. Moreover, in both arrangements of Figures 4 and 5, the outputs of these couplers 34, 38, 42, and 46 are preferably applied to two feedback control circuits (the couplers 34 and 46 to The output of a circuit of this type to generate control signals related to their VCA 32 and 44 and the couplers 38 and 42 26 This paper size applies to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) (Please read the notes on the back before filling in this page) Qin Bing ---------- Sud 143 A7 B7-Printed by the Consumers' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 5 ^ Invention Description () 24 to 1st The output of such circuits to generate the control signals for these VCAs 36 and 40). In Figure 5, the output of the above-mentioned combiner 34, the Lt * (l-gi) signal, is applied to the above-mentioned Cout combiner 58 at a scale of +1, and at a scale of 4 * 1, to The above-mentioned Sout coupler 60. The output of the above-mentioned combination 5 and 46, the Rt * (l-gr) signal, is applied to the above-mentioned C_combiner 58 at a +1 scale, and at a scale of -1 to the above-mentioned Sout combination.器 60。 60. The output of the above-mentioned combiner 38, the 1/2 * (Lt + Rt) * (l-ge) signal, is applied to the above-mentioned Lout combiner 56 'at a +1 scaling ratio and is scaled by a +1 The ratio is applied to the R_coupler 62 10 described above. The output of the above-mentioned combiner 42, the l / 2 * (Lt-Rt) * (l-gs) signal, is applied to the above-mentioned Lout combiner 56 at a scale of +1, and is a +1 of The scaling is applied to the RQUt coupler 62 described above. Unlike these prior art adaptive matrix decoders, their control signals are generated from their inputs. The present invention preferably uses a closed-loop 15-control, where they can provide an output of The size of the signal can be measured and fed back to provide the above-mentioned adaptive control. In detail, unlike the open-loop system of the pre-existing technology, the above-mentioned undesired signals related to the non-essential direction are canceled without relying on the precise matching of their signals and the characteristics of the control path 'and their closed-loop groups State, which can greatly reduce the needs related to the accuracy of the above 20 electronic circuits. Ideally, irrespective of the shortcomings of their actual circuits, the above-mentioned decoders "keep the same size" configuration, in any source that feeds the above-mentioned 1 ^ and Rt inputs with known relative size and polarity, from the above-mentioned desired output In the sense of generating such signals, and ignoring signals from elsewhere, it is “complete” 27 paper standards are applicable to Chinese National Standard (CNS) A4 specifications (210 X 297 mm) il — ίιιί-· I — I — III Order illll!-(Please read the precautions on the back before filling out this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 510143 A7 ——_ B7 ___ V. Invention Description () 25 US dollars ". The above " Knowing the relative magnitude and polarity " means that they and the Rt input represent a source signal at a basic output direction or at a position between their adjacent basic output directions. Consider again their equations 9, 10, 11, and 12, it will be seen that 5 The total gain of each variable gain circuit incorporating a VCA is a subtraction arrangement of the form (1-g). Each VCA gain can be determined from One The value changes up to but does not exceed 1. Correspondingly, the variable-gain-circuit gain (leg) can change from extremely close to 1 and down to zero. Therefore, Figure 5 can be redrawn as Figure 6, Among them, each VCA and the associated subtractor have been replaced by a single VCA 10, and their gains are changed in the direction opposite to the VCA in Figure 5. Therefore, each variable gain- The gain of the circuit (l_g) (for example, a VCA with a gain of ng " is used to realize it, and their outputs are as shown in Figures 2/3, 4, and 5 subtracted from the output of a passive matrix Divide) by a corresponding variable-gain-circuit gain "h" (for example, by using a single VC A above a passive matrix output with a gain of 15 gains " h " If the characteristics of the above-mentioned gain "(Ι-g)" are the same as the gain nhn, and if their feedback circuits are functioning, the necessary signal pairs can be maintained between Equal, the configuration in Figure 6 is equal to the configuration in Figure 5 and will deliver the same output . Indeed, all the disclosed configurations 20, 2/3, 4, 5, and 6 are equal to each other. Although the configuration in Figure 6 is equivalent to their previous configuration and has the same function, it should be noted that the passive matrix components mentioned above are not explicitly shown in their output, but are implicit. In these previously configured static or uncontrolled conditions, the gain g of their VC A will be reduced to 28. This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm)） ninna ^ inn ϋ ϋ 0 ln ϋ II nn such as 5, I nnnnnnn I (Please read the precautions on the back before filling out this page) 510143 Α7 Β7-Printed by the Ministry of Economic Affairs • Intellectual Property • Bureau of Consumer Cooperatives () 26 A small value of iL. In the configuration in Fig. 6, the corresponding uncontrolled condition is caused by the gains h of all VCAs rising to their maximum values, or close to it. In a nutshell, referring to FIG. 6, the " left " output of the above-mentioned passive matrix is also the same as the above-mentioned input number Lt, which is applied to a gain h ,, left, VCA 04, to produce The above-mentioned intermediate signal ^ *. The "right" output of the above-mentioned passive matrix is also the same as the above-mentioned input signal Rt, and is applied to a "right" VC a 70 with a gain hr to generate The above intermediate signal Rt * hr. The above-mentioned "center" output from the passive matrix of combiner 2 is applied to a "center" VCA 66 with a gain he to generate an intermediate signal 1/2 * (Lt + Rt) * hc. The above-mentioned "peripheral" output from the passive matrix of the combiner 4 is applied to a VCA 68 with a gain of 115, around, and VCA 68 to generate an intermediate signal 1/2 * (L "Rt) * hs. Sincerely As explained above, the gain h of their VCAs and the gains g of their VCAs operate in reverse, so that the characteristics of their h gain 15 are the same as their (I-g) gains. The generation of the control voltage The analysis of the control signals developed in the embodiments described so far helps to better understand the present invention and explain the meaning of the present invention, how it can be used to derive five or more from a pair of audio input signal streams. In the following analysis, each of them is associated with one direction. In the following analysis, their results will be illustrated by considering an audio source, which rotates around their audience in a clockwise direction in a circle, starting from the rear , Pass left, front, right, and back. The variable α is the above-mentioned angle (degree) measurement with respect to the image of a listener, 0 degrees is at the back, 29 paper standards are applicable to China National Standard (CNS) A4 (210 X 297 mm) ------- -------- ^ --------- ^ (Please read the notes on the back before filling out this page) A7 B7 V. Description of the invention () 27 l 乂 and 180 degrees in the center The preceding equations are related to α: They input the magnitudes Ltr and Rt, which are as follows

Lt = cos π

Rt sin π (a-9〇y — 360 (a-9〇y — 360 (Equation 17A) (Equation 17B) 10 15 Printed by a member of the Intellectual Property Bureau of the Ministry of Economic Affairs and a Consumer Cooperative) 20 Their parameters α and the size of the above input signal There will be a one-to-one mapping relationship between the ratio to polarity; the use of α will lead to a more convenient analysis. When α is 90 degrees, Lt is finite and Rt is zero, that is, only left When α is 180 degrees, Lt and Rt are equal and have the same polarity (before the center). When α is 0, Lt * Rt are equal but have opposite polarities (after the center). Sincerely as follows To further explain, the specific value 'of their concern' will occur when "the difference is 5 dB from ^ and has the opposite polarity •, which will produce an alpha value of 31 degrees on either side of zero. In fact, he Waiting for the left and right, the loudspeaker is usually further forward than + / • 90 degrees (for example, +/- 30 to 45 degrees) relative to the center, so that ^ does not actually represent the above relative audience The angle is an arbitrary parameter that exemplifies the rotation of the disk. In the middle of the horizontal axis (^ = 180 degrees), it represents the front of the center, and their left and right extremes (α = 0 and 360), which represents the latter side. As discussed in relation to the illustration of Figure 3, one The convenience and practical relationship between the gain of one of the feedback-derived control systems to VCAA can keep their product as a constant. In these index-controlled VCAs, one gain is increased and the other gain is controlled in the feed. Below, this is the same as in the embodiment of FIG.

(Please read the precautions on the back before filling this page) 510143 A7 B7 gl'gr V. Description of the invention () 28 will automatically occur when the same control signal is fed to both of the above pair. Lt and Rt are used to indicate their input signals' to set the product of their VC A gains gi and gr so that it is equal to 1 / a2, and assuming a sufficiently large loop-gain, the final pushes can be made equal, Figure 3 The feedback-derived control system can adjust the gain of their VC A so that the following equations will be satisfied: | lr |. (Lg /) = | i? R |. (L ~ gr) (Equation 18 In addition, (Equation 19) Obviously, in their first equation, the absolute magnitude of these Lt and Rt is 10 is not important. The result depends only on their ratio Lt / Rt; this is called X. From the second equation instead of § "Entering the first equation, you can get a quadratic equation of g |, which has a solution (the other root of the above quadratic equation does not represent a real system) -------- ---- Install—— (Please read the intentions on the back before filling in this education> gl X 'a1-a2 -f ^ / a2 (^ f2-a2m2 · X-a2 -l · a2 x) X -a1 (Equation 20) Line 15-Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economy 20 Draw the rotation angle a of gi and gr to the above-mentioned disk, and you can get Figure 7. As expected, gi will be from the back An extremely low value, rising to the above input only represents a maximum value of 1 when left (α = 90), and then will fall back to a low value related to before the center (α = 180). To the right above In the middle, the sagittal system remains extremely small. Similarly and symmetrically, except for the middle of the right half of the above-mentioned turn, the gr system is very small, and when α is 270 degrees (right only), it will rise to i. The result is the Lt / Rt of the above feedback-derived control system. The sum / difference feedback-derived control system described above is exactly the same

A7 ------- ~ — Β7 The invention statement printed by the Consumers' Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs (5) 29 (Please read the note on the back * t before filling this page). The role of the method can produce as in Chapter 8 The sum gain shown in the figure is again based on the relationship between the difference and the center of the gain gain. As expected, the above sum gain will be # to 1 'in the above ~ 刖 place and down to _ Low value, and the difference gain mentioned above will rise to 丄 after the above. 5 The VCA gain of the above feedback-derived control system depends on the exponent of the control voltage as in the above-mentioned preferred embodiment, and the control voltage depends on the logarithm of the gain. Therefore, from the above equations, the equations related to their Lt / Rt and sum / difference control voltages can be derived, that is, the comparators of the feedback-derived control system described above, and the comparator J of FIG. 3 ,Output. FIG. 9 shows an embodiment in which the maximum and minimum values of the control signals are +/- 15 volts, their left / right and sum / difference control voltages, the latter being inverted (ie, effective Difference / sum). Obviously, other scaling is possible. The curve in section 9 will cross at two points. The signal at one point, 15, represents an image to somewhere to the left of the above audience, and the other to somewhere in the first half of the above. Due to the inherent symmetry of their curves, these crossing points are exactly halfway between their α values corresponding to adjacent basic directions. In Figure 9, they occur at 45 and 225 degrees. Their pre-existing skills (for example, US Patent No. 5,644,640 by the inventor James W. Fusgate 20) show that it is possible to derive a further control signal from the two main control signals, which is connected to The larger (more positive) or smaller (less positive) of the two, although the above-mentioned pre-existing techniques are to derive their main control signals in different ways, and to make the control signals used differently . Figure 10 illustrates an example of a 32-sheet paper equivalent to the smaller of the curve in Figure 9. Applicable to China National Standard (CNS) A4 (21 × 297 mm) A7-Ministry of Economic Affairs «: Property I Staff Printed by the Consumer Cooperative V. Invention Description () 30 ^ 5 Tiger. This derived control will rise to a maximum value when α is 45 degrees, that is, the value at which the two original curves cross. The maximum value of the above-mentioned derived control signal may not be expected to rise to its maximum value at α = 45 accurately. In their actual embodiments, the above descriptions represent the basic direction of the left-back derivation, and it is best to be close to the above, that is, ′ has an α value lower than 45 degrees. The correct position of the above maximum value can be moved by offsetting (adding or subtracting a constant) or scaling one or both of the above left / right and sum / difference control signals, so that their curves are being taken. Before a more-positive or-negative function, it can be crossed at a better α value. 10 For example, Figure 11 shows the same operation as Figure 10 above, except that their sum / difference voltages have been scaled by 0.8. The result is the maximum value mentioned above, which will now occur at α = 31 degrees. In the exact same way, a second new control signal can be derived by comparing the left / right control of the above-mentioned reverse phase with the sum / difference of the above-mentioned reverse phase and adopting a similar offset or scaling down, The maximum value occurs in a predetermined position corresponding to the right rear of the listener, a desired and predetermined α (for example, 360-31 or 329 degrees, 31 degrees on the other side of zero, and the left rear Symmetric). It is left / right upside down in Figure 11. Figure 12 shows the effect of applying the above-mentioned derived control signal to VCA 20, which can make most of the positive values and bring a gain of 1. Just as the gains brought by their left and right VCAs can be raised to 1 at their left and right basic directions, so that these derived left-left and right-right VC Α gains can be located in a signal, When it is at a predetermined position (in this example, α = 31 degrees on either side of zero), it will rise to 1, but for all other positions, it will be kept at 33. The paper size applies the Chinese National Standard (CNS) A4 specification. (210 X 297 mm) ------------- install -------- order --------- line (please read the precautions on the back before filling (This page) 510143 A7 B7 V. Description of invention () 31 10 15 Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs of the Consumer Cooperatives 20 is extremely small. Their similar results can be obtained by their linearly controlled VC A. The curves related to the disk rotation parameter α by their master controllers are different, but they can be scaled or compensated by the appropriate tUH train to cross at their selected points, so that they can borrow a smaller operation To derive another control voltage related to a specific image position outside their first four basic directions. Obviously, it can also reverse their control signals, and some new control signals can be derived by using larger (corrected) rather than smaller (more negative) '. § The main control signal is a modifier that moves their crossing point before adopting their larger or smaller ones, and may additionally include a non-linear operation to replace or add a offset or scaling ^ Obviously The above-mentioned modified body may allow the generation of the above-mentioned another control voltage, and their maximum value is at most located at any desired ratio of the size and relative polarity of the 1 ^ and Rt (input signal). An adaptive matrix with more than four outputs Figures 2 and 4 show a passive matrix that can be added to the adaptive cancellation term 'to counteract unwanted crosstalk. In these cases, four possible offset terms can be derived via four VCA's, and each vca can be derived at one of the four basic directions and with one from the four outputs (left, The center, right, rear) dominates a source corresponding to the output, and achieves a maximum gain of usually one. The above-mentioned system is perfect in the sense that one of the signals rotated between the upper two adjacent basic directions produces little or no output other than the one corresponding to the upper two adjacent basic outputs. This principle can be extended to active systems with more than four outputs. In these cases, the above systems are not, perfect, but they are not

, · — ^^ ----- install * -------- order ---------- '(Please read the precautions on the back before filling out this page) 510143 A7 B7 V. Invention Note (32) The signal of hope can still be fully cancelled, and the result will not be harmed by crosstalk in the hearing. For example, you can see the six output signals in Figure 13. FIG. 13 is a functional and schematic diagram of the active matrix of a part made by Lennon according to the present invention, which helps explain the way to obtain more than four outputs. 5 Figure 14 shows the derivation of the six cancellation signals useful in Figure 丨 3. First refer to Figure 13, which has six outputs: front left (Lout), front center (Cout), front right (Rout), rear center (or around) (Sout), rear right (RB〇ut), and rear left ( Cout). As far as their three front and surrounding outputs are concerned, the above-mentioned initial passive matrix has a four-output system (a direct 10 Lt input, the above Lt plus Rt is scaled by 1/2) And applied to a linear combiner 80 to generate a combination before the center, the above-mentioned Lt minus Rt is scaled by 1/2 and applied to a linear combiner 82 to generate a combination before the center, which is the same as a direct Rt input) . By applying Lt scaled by one to Rt scaled by one -b, it is applied to a linear combiner 84, and Lt scaled by one 15b and scaled by one one Rt, applied to a linear combiner 86, will result in two additional rear outputs, left rear and back, and their inputs are based on different combinations of the equations LB0Ut = Lt- b * Rt and RB〇ut = Rt- b * Lt Corresponding. Here, b is a positive coefficient usually lower than 1, for example, 0.25. It is worth noting that the symmetry described above is not important to the present invention but can be expected in any practical system. In Figure 13, in addition to their passive matrix terms, their output linear combiners (88, 90, 92, 94, 96, and 98) can receive as much cancellation as needed for their passive matrix outputs Proactive offsets (online 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, and 122 35 This paper standard applies to China National Standard (CNS) A4 specifications (210 X 297 mm) ------------- install --- (Please read the precautions on the back before filling out this page) --line · Shengji Ministry of wisdom Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 510143 A7 ------- ^ _ V. Description of Invention () 33 above). These terms include combinations of the aforementioned inputs and / or their inputs multiplied by the gain of their VCA (not shown), or a combination of the aforementioned inputs and the aforementioned inputs multiplied by the gain of their VCA. As mentioned above, these VCAs can increase their gains in terms of control, and the basic input conditions are raised to! , And 5 other conditions are largely small. The configuration in Figure 13 has six basic directions provided by their input Lt * Rt in the defined relative size and polarity. Each of them should cause them to come only from the appropriate, output signals described above. The other five The output signals are largely canceled. As far as the input conditions of a signal 10 representing a disk turned between two adjacent basic directions are concerned, their output corresponding to the basic direction should have signal delivery, but the remaining output should deliver little or no signal ^ Therefore As far as the mother-to-one output is concerned, in addition to the passive matrix described above, it is generally expected to have several offset terms (in fact, more than the two shown in Figure 13), each of which corresponds to each other basic direction An input corresponds to an undesired output 15. In fact, the arrangement of FIG. 13 can be modified to eliminate the above-mentioned center S_output (thus eliminating these couplers 82 and 94), so that the above-mentioned center is only one of the left and right rear plates. Turn halfway, instead of the basic direction of 1/6. In terms of the six-output system or its five-output other types in Figure 13, 20, there will be six possible offset signals. Four Derived from two pairs of VCAs as part of their left / right and sum / difference feedback-derived control systems, plus two derived from left and right VC A controlled by them as described above (See also the embodiment of Figure 14 described below). The above six VC A increase cups are based on Figure 7 (g | left and gr right), Figure 8 (gc and difference from @ 3), and ________ 36_ This paper scale is suitable for the standard of one hundred households (CNS) ) A4 specification (21G X 297 public meal " 1 ^ a ^ M ------- order --------- (Please read the precautions on the back before filling this page) 510143 " economic Printed by Ministry of Intellectual Property, Parent Employee Consumption Cooperative A7 ____B7__ V. Description of the Invention () 34 Figure 12 (gib left rear and grb right rear). Their offset signals are as follows, using the calculated coefficients, or Otherwise it is chosen to minimize unwanted crosstalk and add to their passive matrix terms. By considering their input signals and the 5 VCA gains related to each other basic direction, each basic output can be achieved It is necessary to cancel the blending coefficient, and remember that their VCA gains can rise to 1 only for the signals at the corresponding basic directions mentioned above, and decrease rapidly from the image as the image moves away. Therefore, For example, in the case of the above left output, they need to consider their front, right, rear, and center only. (In the above five output cases, it is not a real basic direction), and the signal conditions on the left. Consider the left output related to the five-output modifier in Figure 13 in detail, Lout. It includes the above from The term of the passive matrix, Lt. When the above input is in the center, in order to offset the above output, when Lt = Rt and ge = 1 15 is exactly the four-output system in Figure 2 or 4 which will require The above item · l / 2 * gc * (Lt + Rt). When the above input is behind the center, or somewhere between their center and the front right (and thus including the back right), it is again just as the second or The four-output system in Figure 4 will require -l / S-g / iLrRt) to offset the above output. When the above input indicates the left rear, in order to offset the output of the above 20, it will need a signal from the left rear VCA, and their gain glb will change according to Figure 12. This obviously makes it possible to deliver a significant cancellation signal only when the aforementioned input is located in the area to the left. Since the above left-hand rear can be regarded as only somewhere between the left-hand front represented by [^ and the center rear represented by 1/2 * (Lt-Rt), it will expect the left-hand rear VCA described above to operate in that Etc.-_ ^ _ 37 This paper size applies to China National Standard (CNS) A4 (21Q x 297 Gongchu) ------------- Installation -------- Order-- --- 11—line (Please read the precautions on the back before filling this page) A7

V. Description of the Invention (35) One of the signals printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs is above. There are a variety of fixed combinations that can be used, but by using the signals that they have long passed left and difference VC4, that is, the sum of g, Lt and 1/2 * gs * (Lt-Rt). The above combination will provide a better offset related to these rotations and the above-mentioned basic left rear itself, depending on the position of the signals which are incorrectly located at the rear left above and within their area 5. It should be noted that at this position, which can be regarded as the middle left and rear left, both gl and gr have a lower limit than 1. Therefore, Lout's equation about expectations will be:

Lout = (LtH / 2 * ge * (Lt + RtH / 2 * gs * (LrRt) -x * & b * ((gl * Lt + gs * l / 2 * (LrRt)) 10 (Equation 21) above The coefficient X can be derived experimentally, or when a source is in the above-mentioned region of the left-left basic direction, from the consideration of their precise VCA gains. The above term [Lt] is the above-mentioned passive matrix term. These terms l / 2 * gc * (Lt + Rt), -l / 2 * gs * (Lt-Rt), and l / 2 * x * gib * ((gl * Lt + 15 g ^ l / 2 * (Lt-Rt )), Which represent some cancellation terms (see Fig. N), which can be combined with Lt in a linear combiner 88 (Fig. 13) in order to derive the above-mentioned output audio signal Lout. As explained above, where There may be more than two (100 and 102) crosstalk cancellation terms input shown in Figure 13. R_ related equations are derived by the same principle, or by symmetry: 20 R—KRtH / VgcYLt + Rt) Ten l / 2 * gs * (LrRt) -l / 2 * x * & b * ((gr * Rrgs * (LrRt)) (Equation 22) The above term [Rt] is the above passive matrix term. The The terms -l / 2 * gc * (Lt + Rt), l / 2 * gs * (LrRt), and -l / 2 * x * glb * ((gr * Rrgs * (LrRt))) represent some offsets Term (see Figure 14), they can be used in the linear combiner 98 (38 ▼ — Γ --- r I-- -^ -------- ^ --------- (Please read the notes on the back before filling this page) The dimensions are applicable to China National Standard (CNS) A4 (210 X 297 mm) ) 510143 A7 B7 V. Description of the invention () 36 Figure 13) Combined with Rt in order to derive the above-mentioned output audio signal ruler. ^ As explained above, there may be more than what is shown in Figure 13 Shows two (12 and 122) two-string tone cancellation terms input. The above-mentioned center front output, Cout, contains the above-mentioned passive matrix 5 terms 1/2 * (Lt + Rt) plus they are as above four The left and right offset terms related to the individual-output system, (Equation 23) There is no obvious offset term after the left, center, or right rear. They are passed through the above (four weeks, the above Among the four-outputs) effective rotation between the left 10 and the right front, and it has already been canceled. The above term l / 2 * (Lt + Rt) 'is the above passive matrix term.-丨 / 2 * gl * Lt and -l / 2 * g, Rt, represent some cancellation terms (see Figure 14), they are applied to their inputs W) 4 and 106, and the linear combiner 90 (section 13 Figure) To a scaled version of Lt and Rt are combined to derive the output audio signal of 15 C〇ut. As far as their left-left outputs are concerned, as mentioned above, the above-mentioned initial passive matrix 'is Lt-b * Rt. In the case of a left-only input, when gpi, it is clear that the above-mentioned required offset term is thus. For a right-only input, when gr = 1, the above-mentioned offset term is + b * gr * Rt. In terms of a center input, 20, where ^ = Rt and ge = 1, the above-mentioned unwanted output Lnb * Rt from the passive term can be offset by (lb) * gc * l / 2 * (Lt + Rt) . The above right-right offset term is -grb * (gr * Rt-l / 2 * gs * (L 「Rt)), which is the same term used by Rout, and has an optimized coefficient y, which can be again Achieved by experiments or calculated from the VC A gain in the above left or right conditions. Therefore, 39 paper standards are applicable to the Chinese National Standard (CNS) A4 specification (21〇X 297 public love) ------ ------ Install i I (Please read the notes on the back before filling out this page) Order:-• Line-4 Printed by the Ministry of Economic Affairs Intellectual Property Brother Employee Consumption Cooperative Printed by the Ministry of Economic Affairs Intellectual Property Bureau Employee Consumption Cooperative 510143 A7 B7 ____ 5. Description of the invention () 37 LB〇ut = [Lt-b * Rt] -gi * Lt + b5iegr * Rr (lb) 5, egc * 1/2 * (Lt + Rt) -y * grb * (gr * Rt-gs * l / 2 * (LrRt)) (Equation 24) Similarly, RB〇ut = [Rt.b * Lt] -gr * Rt + b * gi * Lr (lb) sitgc * l / 23 |! (Lt + Rt) -y * glb ^ 5 (g, * Lt + gs * l / 2 * (LrRt)) (Equation 25) For Equation 24, the above [Lrb * Rt], is The above passive matrix terms and their terms -g 丨 * Lt, + b * g, Rt,-(lb) * gc * l / 2 * (Lt + Rt), and 彳 5 ^, 仏 * 1145 * 1/2 * (1 ^: ^)), which represent their offset terms (see Figure 14). Device 92 (Figure 13), combined with Lt-bRt 10, in order to derive the above-mentioned output audio signal LB0Ut »As explained above, there may be more than two (108 and 110) shown in Figure 13 ) Input of two crosstalk cancellation terms. For Equation 25, the above [Rrb * Lt] is the above-mentioned passive matrix term 'and their terms -gr * Rt, b * Lt * g 丨, -l / 2 * (lb) * gc * (Lt + Rt) 15, 彳, 1, (81 * 1 ^ 4 ^ * 1/2 * (1 ^ 仏)), which represent their offset terms (see Figure 14) ), They can be combined with Rt-bLt in the linear combiner 96 (Figure 13) in order to derive the above-mentioned output audio signal RBout. As explained above, there may be more than shown in Figure 13 Two (116 and 118) two crosstalk cancellation term inputs. 2 In fact, all coefficients may need to be adjusted to limit the loop of the feedback-derived control system described above that cannot accurately deliver equal signal levels. -Gain and other imperfections are compensated, and other combinations of the above six cancellation signals may be used. Of course, these principles can be extended to those who have more than five or six .-- ^ --- 1 L-! ---- Equipment -------- Order · -------- (Please read the precautions on the back before filling out this page) Printed by the Property Cooperative Consumer Cooperative 510143 A7 ______B7_ V. Description of Invention () 38 Examples of output. Some additional control signals are derived from the left / right and sum / difference feedback parts of the feedback-derived control system by applying the above-mentioned scaling to compensate or non-linearly process them. The two main control signals allow them to generate an additional offset signal via some VC A whose gain can be increased to a maximum at other predetermined alpha values of 5 desired. The above synthesis procedure that considers each output in the presence of a signal at each other fundamental direction will produce the appropriate terms and coefficients that they can use to generate additional outputs. With reference to Figure 14, their input signals Lt * Rt are applied to a passive matrix 130, which can generate a left matrix signal output from the Lt input, a right matrix signal output from the Rt input, and a The center output of a linear combiner 132. The inputs of this combiner are Lt and Rt, each of which has a scaling factor of +1 / 2, and an output from the periphery of a linear combiner 134. The four inputs of this combiner are respectively For them, Lt and Rt have a scaling factor of +1 / 2 and · 1/2. The basic directions of the passive matrix mentioned above are specified as "left," "center", "right", and "around". They are aligned with each other in the basic direction above the axis that is perpendicular to each other, and so on For iso-directional markers, their left lines are adjacent to their center and surroundings; their surroundings are adjacent to their left and right, and their left and right passive matrix signals are applied to a first pair of them. Variable gain circuits 136 and 138, and the associated feedback-derived control system 140. Their center and surrounding passive matrix signals are applied to a second pair of variable gain circuits 142 and 144 'and to Associated feedback-derived control system 140 〇 ------------ • install ------- order · --------- line (please read the back first (Please fill in this page again) 41

510143 Printed by the Consumer Property Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs A7 B7 V. Description of Invention (39) The above-mentioned “left π variable gain circuit 136 includes a voltage-controlled amplifier (VCA) 148 with a gain g | Combiner 150. The output of the above-mentioned VCA * is in the above-mentioned combiner 150, subtracted from the above-mentioned left passive matrix signal, so that the total gain of the variable gain circuit is (1-§1) 5 and the above-mentioned The output of the variable gain circuit at the output of the combiner constitutes an intermediate signal, which is (l-gl) * Lt. The output signal of the above VCA 148 forms an offset signal, which is gi * Lt. The above π is right. The variable gain circuit 138 includes a voltage-controlled amplifier (VCA) 152 having a gain gr and a linear combiner 154. The output of the VCA is contained in the combiner 154, 10 from the right passive matrix signal described above. Subtract so that the total gain of the above-mentioned variable gain circuit is (1-gr) 'and the output of the above-mentioned variable gain circuit at the combiner output constitutes an intermediate signal, which is (l-gr) * Rt. The above VCA Output signal grRt of 152, It constitutes a cancellation signal. They (丨 丨 ... ^ and (l-gi) * Lt: the intermediate signal constitutes a first pair of intermediate signals. The relative size of the 15th pair of intermediate signals is expected to be Push to the same direction. This is accomplished as described below, 'with the help of its associated feedback-derived control system 140 °, the "center" variable gain circuit 142 described above, including a voltage controlled amplifier with a gain gi (VCA) 156 and a linear combiner 158. The output of the above 20 VCA is in the above-mentioned combiner 158, which is subtracted from the central passive matrix signal described above, so that the total gain of the variable gain circuit is (l- gc), and the output of the variable gain circuit at the output of the combiner constitute an intermediate signal, which is l / 2 * (l-gc) * (Lt + Rt). The output signal of the above VCA 156 is l / 2 * gc * (Lt + Rt) constitutes a cancellation signal. 42 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm) • 丨 .1- 丨 丨 丨 丨 丨 丨 丨 丨 丨 丨丨 丨 丨 Orders 丨 丨 丨 丨 丨 丨 丨-(Please read the notes on the back before filling this page) 510143 A7 B7 Shengji Ministry of Mind «· Printed by property consumer cooperatives V. Invention description () 40 of the above" quota "variable gain circuit 144, which includes a voltage-controlled amplifier (VCA) 16 with a gain gr and a linear combination 162. The output of the above-mentioned VCA is' in the above-mentioned combiner 162, and the passive matrix signals are subtracted from the surroundings, so that the total gain of the variable gain circuit is 5 (i-gs), and The output of the variable gain circuit at the output of the amplifier constitutes an intermediate signal, which is l / 2 * (i-gs) * (Lt-Rt). The output of the above-mentioned VCA 160 k number l / 2 * gs * (Lt-Rt) constitutes a cancellation signal. The IGYl-gdYLt + RtWalGYl-gdYLt-Rt) intermediate signals constitute an intermediate signal of a second pair. The relative magnitude of this second pair of intermediate signals is expected to be pushed to equal. This is accomplished as described below, with the help of its associated feedback-derived control system 146. The above-mentioned feedback-derived control system 140 associated with the first pair of intermediate signals includes two filters 16 and 166 which can receive the outputs of their combiners 15 and 154, respectively. The output of their corresponding filters is applied to their 15 logarithmic rectifiers 168 and 170, and they will be able to rectify and generate logarithms of their inputs. The rectified and logarithmic outputs described above are applied to a linear combiner 172 with opposite polarities, and their output, which constitutes a subtraction of one of their inputs, is applied to a non-inverting amplifier 174 (these devices 172 and 174 correspond to the size comparator 30 in FIG. 3). Subtracting their logarithmic signals, 20 will provide a comparison function. As mentioned above, this is a practical way of presenting a comparison function in the analog domain mentioned above. In this case, these VCAs 148 and 152 are the type of the inverse of the control input that is inherently used by them, and therefore the inverse of the control output of the log-based comparator described above. The output of the above amplifier 174 is composed of their VCA 148 and 152 43. This paper size is applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) — 1 — !! —! — · I — II! 1 Order · 111! 1 I (Please read the precautions on the back before filling out this page) 510143 Printed by A7 B7, Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs V. Description of Invention () 41 Related control signals. As mentioned above, if it is realized digitally, it is more convenient to divide by their two sizes and use the resulting value as a direct multiple related to their V C A function. As we learned above, these filters 1 μ and 166 can be derived experimentally, and provide a response that can attenuate low and very high frequencies 5 and a modest rise response across the audible range. These filters do not change the frequency response of the output signals. They only change the control signal and VCA gain of the feedback-derived control system described above. The above-mentioned feedback-derived control system 10 146 of the second pair of intermediate signals includes two filters 176 and 178 that can receive the outputs of their VCAs 158 and 162, respectively. The outputs of their corresponding filters are applied to their logarithmic rectifiers 180 and 182, and they will be able to rectify and generate logarithms of their inputs. The above rectified and logarithmic output can be rectified and the logarithm of their input generated. The above rectified and logarithmic output is applied to a linear coupler 184 with phase 15 inverse polarity and they constitute its input. One of the subtracted outputs is applied to a non-inverting amplifier 186 (the devices 184 and 186 correspond to the size comparator 30 of FIG. 3). The feedback-derived control system 146 described above is the same in operation as the control system 140. The output of the above-mentioned amplifier 186 constitutes one of the control signals related to their VCA 158 and 162 20. Their additional control signals are derived from the control signals of the feedback-derived control systems 140 and 146 described above. The control signals ′ of the control system 140 described above apply functions 1 8 8 and 190 of their first and second scaling, offsetting, inversion, and so on. The above control signals of the control system 146 are applied to their paper standards that are applicable to the Chinese National Standard (CNS) A4 specification (21 × x 297). --Γ --- ί ----- installation --- ---- Order · -------- (Please read the precautions on the back before filling this page) 510143 Α7 Β7 V. Description of the invention () 42 ------------ install · II (Please read the notes on the back before filling out this page) Functions 192 and 194 of the first and second scaling, offset, inversion, etc. These functions 188, 190, 192, and 194 may include one or more of the polarity inversion, amplitude offset, amplitude scaling, and / or non-linear processing techniques described above. Moreover, according to the above description, the smaller or larger output of these functions 18 8 5 and 192 and the functions 190 and 194 are accepted by the other smaller or larger functions 196 and 198, respectively. To generate additional control signals that they apply to a left rear VCA 200 and a right rear VCA 202, respectively. In this case, their additional control signals are derived in the manner described above, in order to provide them with control signals that are suitable for generating a left-left offset signal and a right-back offset signal. The above-mentioned inputs to the rear left VCA 200 are obtained in a linear combiner 204 by combining their left and surrounding cancellation signals. The above-mentioned inputs to the rear right VCA 202 are obtained in a linear combiner 204 by subtractively combining their right and surrounding cancellation signals. Or less preferably, the inputs to the above-mentioned VCA 200 and 202 can be derived from their left and surrounding passive matrix outputs and right and surrounding passive matrix outputs, respectively. The output of the above left rear VCA 200 is the above left rear offset signal gib * l / 2 * ((g 丨 * Lt + gs (Lt-Rt)). The output of the above right rear VCA202 is the above right rear offset signal According to grb * 1/2 * ((gr * Lt + gs (Lt-Rt)). The name is printed by the Ministry of Economic Affairs, Intellectual Property, Employee Consumption Cooperative. Figure 15 is a practical example showing the features of the present invention. Schematic circuit diagram of circuit 20. The resistance values shown in them are expressed in ohms. For those that are not indicated, their capacitor values are expressed in microfarads. In Figure 15, "TL074" is a Texas Instruments company Quad Low Noise JFET-Input (High Input Impedance) and General Purpose Operational Amplifiers intended for High-Fax and Audio Preamplifier Applications. Details of these devices, 45 This paper is sized to the Chinese National Standard (CNS ) A4 specification (210 x 297 mm) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 510143 A7 B7 ------ V. Description of Invention () 43 is widely seen in the published literature. An information manual can be found in See above on the Internet: «http: www.ti.com/sc/docs/products/analog/tl074.html». The "SSM-2120" in the figure 15 is a single 5-stone circuit intended for audio applications. It includes two VCAs and two quasi-detectors, which allow logarithmic control based on their size. The gain or attenuation values of the signals they present to the above-mentioned level detectors. Details of these devices are widely known in published literature. A data book can be found on the Internet at: < < http: www .analog.com / pdf71788_c.pdf > >. 10 The following table relates to the items marked at the output of their VCA used in this document, and the items marked above the vertical busbars in Figure 15.

Items used in the above description. Marking at the output of VCA in Figure 15. Marking above the vertical bus in Figure 15. gi * Lt Left VCA LVCA gr * Rt Right VCA RVCA l / 2 * g, (Lt + Rt) Front VCA FVCA l / 2 * gs * (LrRt) Back VCA BVCA gib * ((gi * Lt + gs * l / 2 * (LrRt)) Left back VCA LBVCA g ^ * ((gr * Rrgs * l / 2 * (LrRt)) Right Back VCA RBVCA 15 In Figure 15, the mark 'on the lead from the line to the output matrix resistor is intended to convey the function of their signal, not their source. So, for example, The lead lines leading to the front left output of the first few of them are as follows: 46 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm), --1.IIJ ------ ^- ------ ^ -------- «^ w. (Please read the notes on the back before filling out this page) 510143 A7 B7 V. Description of the invention () 44 Meaning of mark in Figure 15 LT Contribution from Lt input CF Cancel Cancels an undesired output signal related to a previous source LB Cancel Cancels an undesired output signal related to a left back source BK Cancel Cancels an undesired output signal RB Ca related to a later source ncel cancels the undesired output signal LFGR related to the source from the right, the left front gain multiplies the wave to make a disk that passes over the front, and gives a more fixed loudness. It should be noted that in Figure 15 as long as there is VC The polarity of A is praised. The above matrix itself is provided with the inverse value of any item (U2C, etc.). In addition, the π server in Figure 15 is as described in this specification, --- --------- Equipment! (Please read the notes on the back before filling this page) 10 The above mentioned feedback-derived control system. The present invention can use analog, hybrid analog / digital, and / Or digital signal processing technology to realize it, the functions of which are performed by software and / or real estate. They are similar analogous terms like VCA, rectifier, etc., which are intended to include their digital equivalents. Examples In other words, in a digital embodiment, a VCA is realized by multiplication or division. Lights--• Line

Component reference table 2, 4, 14, 16, 18, 20, 22, 26, 46 24, 28 ... Full-wave rectifiers ... Linear couplers 34, 48, 50, 52, 54 ... Combiners 6, 8, 10, 12 ... VCA (Voltage-Controlled 30 ··· Comparator, Operational Amplifier Amplifier) 36 ···, Center ·, VCA 47 This paper size applies to China National Standard (CNS) A4 Specification < 210 X 297 tolerance) 40 ··· "around" VCA 164, 166, 176, 178--filters 56,58, 60, 62, 72, 74, 76, 78 168, 170, 180, 182 ... logarithmic integer … Combiner current combiner 38,42… linear combiner 174,186 ·· non-inverting amplifier 32,6H “VCA 188,190,192,194,196,198 44,70 ·· 丨, right 丨, VCA… function 66 ·· 丨, center ”VCA 200… left rear VCA 68 ·· " around, VCA 202… right rear VCA 80,84,86,132,134,150,154,158,162,172,184,204 ~ linear combiner 82 , 94 ··· combiner 88,90,92,94,96,98… output linear combiner 510143 A7 _____B7 V. Description of the invention (xi 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122… active cancellation term 130… passive matrix 136, 138 142, 144 ... Variable gain circuits 140, 146 ... Feedback-derived control system 148, 152, 156, 160 ... Voltage Controlled Amplifier (VCA) This paper standard applies to China National Standard (CNS) A4 Specifications (210 X 297 mm) ▼ m ----- • Installation --------- Order--------- · (Please read the precautions on the back before filling this page) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs

Claims (1)

8 8 8 8 ABCD patent application scope • A method for deriving at least three audio output signals from two input audio signals, which includes: deriving four audio signals from the two input audio signals, four of which are audio signals It is derived from a passive matrix, which can respond to two audio signals to generate two pairs of audio signals. The first pair of derived audio signals indicates that they are in a direction above a first axis, and the second pair is derived. The audio signals indicate the directions above which they are located on a second axis. The first and second axes are generally perpendicular to each other. Each pair of derived audio signals is processed to generate a corresponding first sum. The second pair of intermediate audio signals, wherein the magnitude of the relative amplitude of the tone Λ 仏 in each pair of intermediate audio signals is pushed to equal; generating a representative of the above-mentioned signal generated by the first pair of intermediate signals. The first output signal of the first direction above the axis of the audio signal is derived. This first output signal is combined with at least each second pair of intermediate audio signals with at least the same polarity. A second component of the signal is generated; generating a second output signal representing a second direction above the axis of the derived audio signal generated from the first pair of intermediate signals; the second output signal is at least the opposite Polarity is generated by combining at least one component of each second pair of intermediate audio signals; generating a third output signal representing a first direction above the axis of the derived audio signal generated from the above-mentioned second pair of intermediate signals; This third output signal margin is generated by combining at least one component of each of the first pair of intermediate audio signals with at least the same or opposite polarity; and optionally ----- —_49 _ · _ This paper standard applies Chinese national standards (CHS) A4 specification (210X297mm) (Please read the notes on the back before filling this page) Order _ A8 B8 C8 、 Scope of patent application A fourth output signal representing a second direction above the axis of the derived audio signal generated from the second pair of intermediate signals is generated, if the third output signal is generated by combining the same polarity, as described above The fourth output signal is generated by combining at least one component of each of the first pair of intermediate audio signals with the opposite polarity, or if the third output signal is generated by combining with the opposite polarity, the fourth The output signal is generated by combining at least one component of at least each first pair of intermediate audio signals with the same polarity. 2. The method as described in item 1 of the scope of patent application, wherein the generation of a first output signal includes making each second pair of intermediate audio signals a component and a passive matrix representing the above-mentioned first direction. The combination of the audio signal 'is composed of a cancellation signal opposite to the passive matrix audio signal; The generation of a second output signal includes combining a component of each second pair of intermediate audio signals with a passive matrix audio signal representing the second direction. The above component is composed of a passive matrix and the passive matrix. The opposite of the audio signal is composed of the offset signal. The generation of a third output signal includes combining a component of each first pair of intermediate audio signals with a passive matrix audio signal representing the third direction. The component is composed of a cancellation signal opposite to the passive matrix audio signal described above; and optionally a fourth output signal is generated, which includes making each first pair of intermediate audio signals a component and a The passive matrix audio signal representing the fourth direction above is combined with the above-mentioned components. The above-mentioned components are composed of a passive moment and the above-mentioned passive moment. " " The opposite of the array audio signal is the offset signal. 3. The method according to item 2 of the scope of patent application, wherein the matrix audio signals' representing the first, second, third, and optional fourth directions, respectively, are generated by the passive signals mentioned above. 4 · The method as described in item 2 of the scope of the patent application, wherein the matrix audio signals respectively representing the first, second, third, and optional fourth directions are passive in most cases. The signals are generated in a linear combiner that combines the components of those signals. 5. The method as described in item 1 of the scope of patent application, wherein the corresponding output signal is generated by combining the paired intermediate signals. 6. The method according to item 1, 2, or 5 of the scope of patent application, wherein the processing technology includes returning each pair of intermediate audio signals that can be used to control the relative amplitude of the corresponding intermediate audio signal pair. 7. The method as described in item 6 of the scope of patent application, wherein the processing technique includes' applying each derived audio signal to a corresponding variable gain circuit, wherein each is associated with each pair of derived audio signals The gain of the associated variable gain circuit is controlled in response to the amplitude of the output of its corresponding variable gain circuit. 8. The method as described in item 7 of the scope of the patent application, wherein each of the variable gain circuits' includes a voltage-controlled amplifier (VCA) combined with a subtractive combiner and having a gain gr. The resulting variable-gain-circuit gains are (1 -g) and their cancellation signals are obtained from the output of these voltage-controlled amplifiers. 9 · The method described in item 7 of the scope of patent application, each of which can be increased --- _51 ___: _ This paper size applies the Chinese national standard (Οβ) A4 specification (21〇χ297 公 楚) (Please (Please read the precautions on the back before filling this page) • 510143 A8 B8 C8 D8 patent application scope benefit circuit 'includes a voltage-controlled amplifier (VCA) with a gain g, its variable-gain -The gain of the circuit is g and their cancellation signals are obtained from the output of these voltage controlled amplifiers. 10 · The method described in item 7 of the patent scope of the patent, the gain of each of the variable gain circuits is so low in terms of their static input signal conditions that their signal outputs are generally some Signals generated by the passive matrix described above. 11. The method according to item 7 of the scope of patent application, wherein the gain of each of the variable gain circuits is so high as to their static input signal conditions, so that their signal output is generally determined by some The signals generated by the passive matrix described above. 12. The method as described in item 7 of the scope of patent application, wherein the gains of the variable gain circuits associated with each pair of derived audio signals are obtained by applying the output of the corresponding variable gain circuits of the pair to To a size comparator that can generate a control signal that can control the gain of the variable gain circuit, and control it. 1 j. The method as described in item 12 of the Shen Qing patent snake enclosure, wherein the corresponding size comparisons can control the gains of the variable gain circuits associated with each pair of derived audio signals so that for certain input signals In terms of conditions, an increase in the size of the output of a variable gain circuit relative to another will cause a decrease in the gain of the variable gain circuit with an increased output described above. 14. The method as described in the scope of patent application 萆 II, wherein the corresponding size comparator can control the gain of the variable gain circuits associated with each pair of derived audio signals, so that for certain input signal conditions ， May 52 This paper size is applicable to China National Standard (CNS) A4 specification (210 X 297 mm) (Please read the precautions on the back before filling this page). Order I: Line. 510143 A8 B8 C8 _ D8 VI 、 The magnitude of the output of the patent-applied variable-gain circuit is increased relative to the other. In the gain of the variable-gain circuit that does not have an increased output, the change will generally not be caused. 15. The method as described in item 13 of the scope of patent application, wherein the corresponding size comparator can control the gain of the variable gain circuits associated with each pair of derived audio signals, so that for certain input signal conditions In terms of increasing the output of a variable gain circuit relative to another, the product of the gains of the variable gain circuits can also be made substantially constant. 16. The method as described in item π of the patent application range, wherein the corresponding size comparator can control the gains of the variable gain circuits associated with each pair of derived audio signals, so that for certain input signal conditions The increase in the output of a variable gain circuit relative to another can cause the gain of the variable gain circuit with an increased output to increase. 17. The method described in item 16 of the scope of patent application, wherein the corresponding size comparators can control the gains of the variable gain circuits associated with each pair of derived audio signals so that for certain input signal conditions The increase in the size of the output of a variable gain circuit relative to the other does not generally cause a change in the gain of the variable gain circuit that does not have an increased output. 18. The method described in item 16 of the scope of patent application, wherein the corresponding size comparators can control the gains of the variable gain circuits associated with each pair of derived audio signals, so that for certain input signal conditions The increase in the output of a variable gain circuit relative to another can also make the product of the gains of these variable gain circuits substantially constant. -—___ 53 _ · _ This paper size applies to Chinese National Standard (CNS) A4 (210 X 297 mm) (Please read the precautions on the back before filling this page) Order | 510143 A8 B8 C8 D8 VI. Application scope 19. The method as described in item 12 of the scope of patent application, wherein the gains expressed by the variable gain circuits in dB are some linear functions of their control voltages, and the comparators of each size have a finite gain, And the output of each variable gain circuit is applied to a size comparator via a rectifier, which can deliver an output signal proportional to the logarithm of its input. 20. The method described in item 19 of the scope of patent application, in which each rectifier has a filter in front of the collar, which has a response that can attenuate low-frequency and extremely high-frequency, and can provide a audible range The rise in the middle eases the response. 21. The method as described in item π of the patent application scope, further comprising: The control signals of the variable gain circuits associated with each pair of passive momentary array audio signals can be derived from the above two, and one or more additional control signals are derived. One or more of the additional control signals are each borrowed. Modifying one or both control signals, and generating the smaller or larger of an unmodified control signal and a modified control signal, or the smaller or larger of two modified control signals, are derived . 22. The method according to item 21 of the patent application, wherein one or both of the control signals are processed by the above-mentioned corresponding signals by inverse polarity, amplitude offset, amplitude scaling, and / or non-linear, and Be modified. 23 · The method as described in item 21 of the patent application scope, which further comprises one or more additional variable gain circuits which can receive a combination of two of the majority of the cancellation signals or a combination of two passive matrix signals As an input, one or more additional control signals can be controlled ----------- 54 This paper size applies to China National Standard (CNS) A4 (210 X 297) 510143 A8 B8 C8 D8, one or more corresponding additional variable gain circuits corresponding to the scope of patent application, so that the gain of these circuits can be used on the input signals, which represent them on the first and second axes In a direction other than the direction, rise to a maximum value; and control one or more additional variable gain circuits by a corresponding one of the one or more additional control signals to generate one or more additional variable gain circuits Cancel the signal. 24. The method according to item 23 of the scope of patent application, wherein at least five output signals are generated by using at least five passive matrix audio signals of each and two or more of the majority of the cancelling signals and A combination of one or more additional cancellation signals, which are the opposite of each passive matrix audio signal, so that the above-mentioned passive matrix audio signals can be used on these input audio signals. A signal associated with a direction other than the direction represented by the matrix audio signal will be substantially canceled by these cancellation signals. 25. The method according to item 1 of the scope of patent application, wherein the size of the audio signal in the first pair of intermediate audio signals can be expressed as: [(Lt + Rt) * (l-ge)], or , Equal to the size of [(Lt + Rt) * (hc)], and the size of [(LrRt) * (l-gs)], or equal to the size of the audio signal in the intermediate audio signal. The size can be expressed as: [Lt * (1 suspected size 'or equivalent [Lt * (hr)] size, this paper size applies to Chinese national standard (_7 ^ 7 ^ 297mm; · (please first Read the notes on the back and fill out this page) ^ J · And [Rt * U-gr)], or equal [Rt * (hr)], where 'Lt and dagger are a pair of audio signals generated by the above passive matrix, Lt + Rt * L "Rt is another pair of tone Λ signals generated by the above passive matrix, (丨 -g.) And he is a gain of a variable gain circuit associated with the Lt + Rt output of the above passive matrix, (i_gs ) And d are the gains of the variable gain circuit associated with the Lt-Rt output of the passive matrix described above (1-§ |) and h | are the variable gains associated with the Lt output 袓 of the passive matrix described above The gain of the circuit, (buxin) and hr are the gains of the variable gain circuit associated with the Rt output of the passive matrix mentioned above. 26 · —The wolf can derive at least three from two input audio signals, each of which is associated with one direction. The method of outputting audio signals includes: responding to the two input audio signals and generating a majority of passive matrix signals with a passive matrix. They include two pairs of passive matrix audio signals, and the first pair is passive. The matrix matrix audio signal represents some directions above the first axis. And the passive matrix audio signals of its second pair represent some directions above the second axis, and the first and second axes are substantially perpendicular to each other; processing the passive matrix audio signals of each pair, In order to generate corresponding first and second pairs of intermediate audio signals, the magnitude of the relative amplitude of the audio signals in each pair of intermediate audio signals is pushed to be equal; from these intermediate audio signal pairs, the majority of the offset signals are derived ; By combining each at least three passive signal audio signals with two or more majority cancellation signals to produce at least three outputs. This paper size is applicable to China National Standard (CNS) A4 specifications (210 X 297). 510143 A8 B8 C8 D8, patent application range signals, these 'cancellation signals' are the opposite of each passive matrix audio signal, so that the above-mentioned passive matrix audio signals can be used on these input audio signals, representing them When the signal is associated with a direction other than the direction represented by the passive matrix audio signal described above, it can be roughly canceled by these signals. 27. The method described in item 26 of the scope of patent application, wherein the processing technology includes' returning each pair of intermediate audio signals to control the relative amplitude of the corresponding pair of intermediate audio signals. 28. If applying The method described in item 27 of the patent scope, wherein the processing technology includes applying each of the passive matrix signals in the above two pairs of passive matrix audio signals to a corresponding variable gain circuit, each circuit including a A voltage-controlled amplifier (VCA) with a gain g combined with a subtraction combiner, where the resulting variable-gain-circuit gain system (1-g) and the cancellation signals are taken from the Output of constant voltage controlled amplifier. 29. The method according to item 28 of the scope of patent application, wherein the gains of the variable gain circuits associated with each pair of passive matrix audio signals are controlled by changing the corresponding variable of each pair The output of the gain circuit is applied to a size comparator, which can generate a control signal capable of controlling the gain of the variable gain circuit. 30. The method as described in item 29 of the scope of patent application, wherein the output of the variable gain circuit corresponding to each pair is applied to a size comparator via a rectifier, which can deliver a logarithm proportional to its input Output signal. The above-mentioned size comparator has a limited gain, with 57— This paper size applies the Chinese National Standard (CNS) A4 specification (210 X 297 mm) (please read the precautions on the back before filling this page),- ! 1 510143 ❿ A8 B8 C8 __ D8 The scope of patent applications and the above-mentioned VCA gain expressed in dB are linear functions / of their control voltages. 31. The method described in item 29 of the scope of patent application, further comprising: deriving one or more additional controls from the above two control signals that can control the variable gain circuit associated with each pair of passive matrix audio signals described above Signals, where one or more additional control signals are each modified by one or both of the control signals, and generate the smaller or larger of an unmodified control signal and a modified control signal, or two The smaller or larger of the modified control signals is derived. j 2 · The method described in item 31 of the patent application, wherein one or both of the control signals are processed by the above-mentioned corresponding signals by polarity inversion, amplitude offset, amplitude scaling, and / or non-linearity. And modify it. 33. The method according to item 31 of the scope of patent application, which further comprises one or more additional variable gain circuits which can receive a combination of two of the majority of the cancellation signals or a combination of two passive matrix signals As an input, one or more additional control signals can control one or more corresponding additional variable gain circuits, so that the gain of these circuits can be represented on these input signals on behalf of them. Rise to a maximum value in a direction other than the directions above the first and second axes; and control one or more additional variables by a corresponding one of the one or more additional control signals Gain circuit to generate one or more additional cancellation signals. 58 This paper size is in accordance with Chinese National Standard (CNS) A4 (210 X 297 mm). Please read the notes on the back and fill in this page), ^? · Line · A8 B8 C8 D8 Patent Application Scope] 4 · The method according to item 33 of the scope of patent application, wherein at least five output signals are generated by using at least five passive matrix tone signals of each, and two or more of the majority cancelling signals and one Or above additional cancellation signals, these cancellation signals are opposite to each passive matrix audio signal, so that the above-mentioned passive matrix audio signals can be used in these input audio signals, which represent them and the above-mentioned passive The signals associated with directions other than the directions represented by the matrix audio signals can be substantially canceled by the canceling signals. (Please read the precautions on the back before filling out this page). Maybe 59 This paper size applies to China National Standard (CNS) A4 (210 X 297 mm)