JPS60149279A - Television signal processing method and television transmission system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for processing the digital audio/data components of individual lines of a time-multiplexed television signal, wherein each line sequentially processes digital audio/data components at a first bit rate. and a video component. The invention also relates to a device, a television transmission system, an associated conversion unit and a receiver using the above method.

Following the August 1982 decision to begin direct satellite broadcasting (DBS) of television programs in the UK by the end of 1982, a committee was created, chaired by Sir Anthony Burt, to discuss technical standards for transmission. I decided to submit a report. The committee's findings were published in November 1982 by the Publishing Bureau in Qmn (18751″D
directBroadcasting by 5ate
llite-Report of theAdvis
ory Panel on Technical T'
Transmission Standards” (part report), but it is
pendent B'roaaoa8tAuthor
ityb Multiplexed Analogue
Component (0-MAOJ) was recommended for DBS, and this recommendation was subsequently approved.

0-MAO method is Independent Broad
castAuthority's Experiment
tal ancl ]) developmentRepO
rt 1 1 8 / 82 ”M A O-A T
eleViSiOnSystem for High
-Quality 5atellite Broadc
Asting (August 1982), this report describes the A-M A O system (the prefix refers to the type of voice and data transmission). contains proposed specifications for two schemes, but the specifications for the O-MAO scheme have been revised in favor of the O-MAO scheme for DBS.The structure of the video waveform. The transition period following the component (which we will refer to as ``e'') has been shortened, resulting in a longer voice/data component.

Figure 1 (this is not to scale) schematically depicts the l-line period of the O-MAO television signal derived from the draft specification, which occupies 64 μs and each line has 20.25 μs. It is divided into a number of bit or sample periods at a clock rate of MHz, and there are 1296 such samples per line. Each line contains the following in the given order:

a - 194 bits - Sync, audio/data b - 4 samples - transition period from end of data C - 15 samples - main clamp period (zero level of color reference J a - s 55 samples - color (0) e = 4 samples - Gray-black transition f - 1o sample - Black level clan 73111 (M level reference) f = 710 samples - Fine detail fY) h - 4 samples - Transient color components to data are time compressed at a ratio of 8:1. Therefore, color information (1) 52.59 /'S is 17-fr 8μ5 (8
55 samples). And R-Y
A color difference signal is placed on every other line, and a B-Y color difference signal is placed on an intermediate line. The luminance component is time compressed at a rate of aj2. Therefore, the brightness information is 52.59μ
s is compressed to occupy d 5.06 μ5 (71 (l samples)). In the case of DBS transmission, the chrominance and luminance components thus compressed are frequency modulated with a bandwidth of 27 MHz, while the wireless A frequency carrier wave is modulated with a digital voice/data component using 2-4 digital phase keying (2-4PSK). The exact nature of the voice/data component has not yet been determined, but <<some examples are given above. It's in the literature.

The above specifications are based on a new report from the European Broadcasting Federation"T
e1evision 5 standards for 6
25-Line 12 GH25atellite Bro
further revised in June 1988 to ensure that each line contains the following in a given order: 8 bits - synchronization, audio/data (data burst) b - 4 samples - end of data Transients from 0-15 samples - main clamp period (color reference zero level) SO1 = 6 samples - set aside for video scrambling (1 = 2154 samples - color (0) g = 704 samples - luminance (Y) SO3 - 6 h = 4 samples set aside for video scrambling - transient to data As is clear from this EBU draft standard, components e and f are missing, component Sol is inserted between components 0 and d, and component g
A component 802 is included between and h.

In addition, the amplitude of the color component has changed and is now equal to the amplitude of the luminance component. However - these variations are not important to an understanding of the invention.

It is also possible to receive DBS broadcasts directly at home by watching the satellite and using a parabolic antenna of appropriate dimensions, and placing a down converter on the antenna side to bring the frequency of the incoming signal to just above the broadcast UHF band. However, it has been pointed out that many households prefer to receive such broadcasts via a couple television wiring system that can simultaneously carry other television programs, thus eliminating the need for multiple antennas. Wiring using such a pull-pull is clearly used when the signal from the satellite is weak, for example because the broadcast is not primarily directed to the country in question, or when the signal is weak because the signal is received from several satellites at different locations. This is advantageous when a coarse antenna array is required.

Chapter 7 of the Part Report deals with the interaction between DBS and cable distribution systems, and the British Cable Television Association believes that even if O-MAO is chosen as the DBS transmission standard, it will still be possible to provide table service. It is reported that there are.

Some examples are given in this Chapter 7, and G-M
It has been reasoned that this type of signal could be transmitted directly onto the table system if suitable for AO. Current cable transmission systems use coaxial cables to carry television programs in the VHF broadcast band.
There is much debate as to whether or not future systems will utilize fiber optic cables. However, many systems established in the future are likely to utilize coaxial tables due to their low construction costs.

As has recently become known, transmitting O-MAO signals over a VHF+-pull transmission system is not as simple as previously thought. Cover, 27
This is because the bandwidth of such a signal, Mn2, monopolizes too much bandwidth and reduces the number of programs that such a table system can carry. In addition, 21
Transmitting voice/data components at rates as high as J, 25 Mbit)/8 poses significant problems for such table systems. However, transmission at such high speeds causes reflections with short delays, while there is also a lower bit rate limit for such cable systems.

It has therefore been suggested that the only way to transport such signals over a Vl (F+-pull transmission system) is to convert the O-MAC signal to a PAL type signal before adding it to the table system. However, such a conversion removes the advantage of time multiplexing of color and luminance components and reintroduces the disadvantages of cross-luminance and cross-color components associated with color subcarrier schemes. More importantly, for example, when a television service is limited to subscribers only, the received DBS signal must be scrambled once before being converted, in order to prevent non-subscribers from receiving it unduly. It is necessary to descramble and then scramble the converted signal again.

In addition, it has been found that the high bit rate of the digital audio/data component (20.25 Mbit/s) makes signal processing difficult, even in the case of television receivers receiving direct broadcasts from satellites.

It is therefore an object of the present invention to provide a method for processing such audio/data components and a television system which overcomes the above-mentioned difficulties.

To achieve this objective, according to the invention, digital audio/
A method of processing a data component, wherein each line sequentially includes a digital audio/data component at a first bit rate and a video component. separated from the television signal and expanded to have a second bit rate, each expanded digital audio/data component occupying a significant portion of a separate period, the period corresponding to the period of one line; the second bit rate is an integer fraction multiple of the first bit rate, and the second bit rate is f
where o is a first bit rate and n is the number of bits in the compressed audio/data component within the television signal;
It is characterized in that when m is the number of bits within one line period at the @10 bit speed, it is larger than f□×i.

Reducing the focus rate of the audio/data component from a first bit rate (e.g. 2045 Mbits/8) to a much lower second bit rate requires circuitry to organize and demodulate the audio/data component. The requirements for this become much simpler.

The invention also provides for transmitting a first time multiplexed television signal having a predetermined bandwidth over a medium whose bandwidth is limited relative to the bandwidth of this first television signal. @2 television signals, where the individual lines of said first television signal are sequentially converted into a digital audio/data component, a temporally compressed color component, and a temporally compressed luminance component. and wherein the audio/data component modulates a carrier wave at a first bit rate, and the carrier wave is frequency modulated by the color and luminance components, wherein the second television signal is a video signal. an lth carrier amplitude modulated by the signal, each line of the video signal sequentially envelops a temporally compressed chrominance component and a temporally compressed luminance component with a corresponding compression ratio; is located at a position corresponding to that in the first television signal, and the second television signal further includes a second carrier wave located outside the first carrier wave, the second carrier wave being located outside the first carrier wave. is the second
modulated by a digital audio/data component at a bit rate of , the discrete periods of which are present within the discrete lines of said first television signal, but stretched, corresponding to the periods of - lines; the second bit rate is an integer fractional multiple of the first bit rate, and the second bit rate is such that fo Let n be the bit rate, and n be the first bit rate.
Let m be the number of bits in a compressed audio/data component in a television signal of m and m be the number of bits in a line period at said first bit rate.

Changing the modulation of the chrominance and luminance components in such a system from frequency modulation to amplitude modulation (preferably vestigial sidebands) immediately increases the bandwidth with no substantial loss of signal quality. Saved. Any scrambling of these components is preserved and, in contrast to the previous proposals, there is no need to descramble and then re-scramble these components. In addition, by preserving the compression rate and the position of the color and luminance components of the frequency modulated signal even within the amplitude modulated signal, the television receiver correspondingly also receives the DBS signal directly even in the television receiver connected to the cable distribution system. The same decoding technology and therefore the same components (particularly integrated circuits) can be used as in the machine.

Stretching the voice/data component reduces the bit rate, which overcomes the problem of reflections with short delays in coaxial cable systems. Also, if this bit rate is chosen to be an integer fraction multiple of the first bit rate, it becomes quite easy to create this second bit rate during conversion, and it is also possible to reproduce the first focus rate on the receiving side. It gets easier. This first bit rate is required on the receiving side for synchronization. The selection of the second bit rate mentioned above means that additional bits need to be added to the decompressed audio/data component.

In such a system, the modulation of the first carrier by the video signal may be vestigial sideband amplitude modulation. The second carrier can then be placed on the vestigial sideband of the modulated first carrier. In addition, in order to easily synchronize on the receiving side, a pulse signal for each line of the video signal of the second television signal is additionally input, and this pulse signal is used as the data of the first '(Z) television signal. / can be placed in a position corresponding to the position of the audio component.

The integer fraction for obtaining the second bit rate in the method or system described above may be less than or equal to one. In a particularly advantageous embodiment, the first bit rate is j.

Additional digital components may be added to the decompressed audio/data component during a small portion of each discrete period. This additional digital component can then carry additional voice/data information.

The invention also relates to an apparatus for use in said method, comprising means for receiving a television signal in which the individual lines sequentially include a digital audio/data component and a video component at a first bit rate; means for reproducing digital audio/data components from the television signal, the apparatus decompressing the reproduced audio/data components at a second bit rate so that each digital audio/data component of the first television signal is the second bit rate being an integer fraction of the first bit rate; times the second bit rate, where fo is the first bit rate and n is the number of bits in the audio/data component within the first television signal;
0, characterized in that it is larger than f, x, where m is the number of bits within one line period at the first bit rate.
The invention also relates to a conversion unit for use in said television transmission system, which means for receiving said first television signal, wherein the individual lines of said television signal are sequentially converted into digital audio/ a data component, a temporally compressed color component, and a temporally compressed luminance component, wherein said digital/audio component modulates a carrier wave at a first focus speed, said digital/audio component modulating a carrier wave at a first focus speed; means for frequency modulating the compressed color and luminance components of the modulated carrier wave, means for frequency demodulating the modulated carrier wave to produce the compressed color and brightness components, and digital audio/luminance components from the modulated carrier wave. and means for regenerating the data components, the transform unit additionally amplitude modulating the demodulated compressed chrominance and luminance components to determine the compression ratio and position of these components on the first carrier. and means for decompressing the reproduced audio/data component at a second bit rate from each line of the first television signal. occupies a large portion of a discrete period 1i15 to the period of the television line, the second bit rate is an integral fraction of the first bit rate, and the second bit rate is an integral fraction of the first bit rate; where the bit rate is the first bit rate, n is the number of bits for the audio/data component in the first television signal, and mtl - the bits in one line period at the first bit rate. f, x.

and how to make the expanded audio/
means for modulating the data component onto a second carrier wave external to the modulation of the first carrier wave, the first and second modulated carrier waves forming a second television signal. Features.

Such a conversion unit additionally comprises a vestigial sideband filter, so that the first carrier wave becomes a sideband of the modulated wave amplitude-modulated by the compressed chrominance and luminance components. It is also possible to provide means for placing a second carrier wave on a sideband of this first carrier wave. The conversion unit further includes means for generating a pulse signal at line rate and applying the pulse signal to the video signal of the second television signal, the pulse signal corresponding to the position of the audio/data component in the first television signal. and means for positioning the device in the position where the device is located.

The devices and conversion units described above convert the digital components into decompressed digital audio/
may additionally include means for adding to the data component;
It may also include means for modulating this added digital component with audio/data information.

The invention also relates to a television receiver for use in the aforementioned television system, which is connected to a transmission medium with limited bandwidth and has selection means for selecting one of several transmission channels. and a first signal processing circuit connected to the selection means for processing the video signal carried by the first carrier wave, the receiver additionally comprising: 2
a second signal processing circuit for processing audio/data information carried by a carrier wave, the second signal processing circuit converting a second bit rate present in the second television signal to a second bit rate present in the second television signal; The present invention is characterized in that it comprises means for regenerating a clock signal corresponding to a first bit rate present in one television signal.

One embodiment of such a receiver is such that the receiver additionally generates a timing signal for processing color and luminance components present in the video signal and includes this timing signal in the audio/data component. means for regenerating a pulse signal, applying the regenerated pulse signal to the processing means such that a predetermined time relationship exists between the pulse signal and the timing signal; It is characterized by comprising means. This pulse signal can also be used to obtain automatic gain control in the receiver.

The receiver may also be a dual standard receiver receiving 20) television signals or frequency multiplexed television signals. A number of signal processing steps are then common to both signals.

The above-mentioned and other features of the invention will become apparent from the following description of the drawings.

The invention will be explained in detail with reference to the drawings.

FIG. 2 is a block diagram of a conversion unit used in the present invention, which converts the received C-MAODB
MA (3) S television signal to cable distribution system
It is used to convert television signals into something suitable for addition. This figure 2 shows a parabolic antenna 1 of suitable dimensions, which is used to receive DBS television signals falling within the 12 GH2 broadcast band. 950 Mn7 and 1, which shifts the frequency of the incoming signal and is just above the UHF broadcast band.
750MH2 and applied to input terminal 4 of the conversion unit via coaxial cable 8. In the conversion unit, the signal present at input terminal 4 is applied to input terminal 5, where it is applied in the usual manner. It is mixed with a local oscillator signal to create an intermediate frequency (IF) signal (the frequency of which is now 184 MHz), which selects the desired television signal.

The bandwidth of the tuner and the resulting IF signal is 27-Mn2, which matches the bandwidth of the DBS signal. Tuning in the zero tuning unit 5 is performed by a selection voltage; (not shown) to connection path 6
the second input of the 0 adder circuit 7, which arrives at the zero adder circuit 7 and is applied to the first input terminal of the adder circuit 7, the output terminal of which adder circuit 7 being connected to the appropriate input terminal of the tuning unit 5. An automatic frequency control (AF, O) voltage is applied to the terminals, which is sent over connection 8, and this AFO voltage is added to the selection voltage to ensure correct tuning of the tuning unit 5. I from 0 tuning unit 5? The signal is amplified by an amplification film 9 and applied to a surface acoustic wave (SAW) filter 10. This filter 10 has a passband of 27 Mn2 centered on the intermediate frequency of 184 MH2. The output signal of the SAW filter 10 is passed through a limiter and a discriminator. The chrominance and luminance video components which are applied to stage 11 and which are IF times signal frequency modulated are demodulated and the baseband video MAO signal is outputted at its output, which is de-emphasized by the de-emphasis stage 14. The discrimination stage 11Fi also creates the AFO voltage, but this A1i'0
Adder circuit using 1 connection path 8 for voltage? added to.

The IF multiplied signal is also added to the limiter and 2-4PSK demodulation stage 1B, where the audio/data component (194 bits at 1.25 Mbit/S) is reproduced.
The voice/data component in the form of bursts at 3 Mbit/S is applied to the voice/data processor 14. This audio/data processor 14 has several functions, one of which is to decompress the audio/data component and reduce its bit rate much lower.
It is shown in detail in the figure 0.20.25 in this figure 8.
A burst of Mpi)/S audio/data components is applied to input terminal A of processor 14 and from there as a first input to phase comparator 15. The second input terminal of the phase comparator 15 is connected to the voltage controlled crystal oscillator 16 or 2045.
Receives an oscillation signal at the clock frequency of MB2. Phase comparator 15 produces a voltage at its output terminal that depends on the phase relationship between its two inputs.

This voltage is applied via a low pass filter 17 to an oscillator (VOO) 16 as a control input. Voltage control is thus provided to this oscillator 16.

The output of the oscillator 16 is applied to a divider 18 where it is divided by 6 and the incoming burst from the 0 input terminal A is also applied to the digital memory 19 creating a second clocking frequency of 8.876 MHz. But this memory 1
9 is in the form of a shift register so that the burst of audio/data components appearing on each line of the FISO-M signal is written to the memory 19 at a clocking frequency of 20.25 Mn2 under the control of the oscillator 16. This audio/
In order for the data component to be successfully carried over a cabling system, this voice/data component must be stretched so that its bit rate is much lower than it is in the O-MAO signal. Stretch the component for 64μs
, this is 62 cycles per frame.
6 lines, corresponding to a line period in which the second television system takes 25 frames, which corresponds to a bit rate of 8.06 for 194 bits of the audio/data component.
This means that it would require 25 Mpi)/S. However, it is difficult to make such a bit rate from the incoming bit rate, and in addition 8.0625 Mbit/
It is also difficult to recover the original clock frequency of 20.25 MH2 from the data of S. Therefore, in the processor 14, 8.0625 Mbit/S is generated in a period as short as 64 μs.
The audio/data component tube is read out at a bit rate higher than , where the bit rate is an integer multiple of the original bit rate of 2OJI6M bits/s (in this example, it is one times the original bit rate).

Therefore the voice/data component is 8.875 during each 64 μS
The bit insertion stage zO is read out under the control of the second clocking frequency of MH2, occupies 194 of the 216 bits at that speed in such a period, and is added to the gated bit insertion stage 20. The second input terminal of B1 is connected to the output terminal of the bit generator 81. The input terminal of the bit generator B1 receives a second clock frequency of 8.8~5 MHz and generates the bits in a predetermined pattern. (which can also be used to carry additional information) These bits are divided into 6 bits each in bit insertion stage 2o.
When the remaining 22 bits of 4aB are added, each 64 bits are added.
- A decompressed audio/data component over a μS (line) period is created and sent to output terminal B of the processor 14. Note that a second clock frequency of 8.8?5 MHz is output from output terminal 0. The burst at input terminal AK6 is also applied to a sync separator circuit 22 which recognizes the sync information contained in the audio/data component and produces an output signal in response to this sync information. This output signal is given to the synchronization pulse generator 2B to generate a pseudo synchronization pulse. This synchronization pulse appears at the output terminal of processor 14, and its purpose will be discussed below.

The video signal exiting the de-emphasis stage 12 is applied to a first input terminal of a gated sync insertion stage 26. A second input terminal of the sync insertion stage 26 receives a pseudo sync pulse from the output terminal of the processor 14. This pseudo sync pulse is incorporated into the video signal during the period previously occupied by 104 audio/data bits (approximately 9.58 μs). The combined sync-video signal emerging from the sync insertion stage 26 is applied to a modulation input terminal of a modulator 27 where the sync-video signal is amplitude modulated and input from the first carrier oscillator 28 to a second input terminal. It is placed on the incoming video carrier wave. The frequency of this video carrier then falls within the frequency band used in cabling systems. One line period (C40) for the percentage depth of modulation of the carrier
The nature of this signal at 64 μs) is shown in Figure 4, and it is clear from Figure 4 that the pseudo sync pulse and its associated rear and front porches (S) are preceded by voice/data components. while the compressed color (0) and luminance (Y) components still occupy the same period as in the O-MAO signal. Therefore, the scrambling and coding of these components within the received O-MAO signal is not altered or impaired in any way by the processing of these components in the -9 processor 14.

As is clear from Figure 4, the pseudo synchronous pulse is one of the carrier waves.
00% modulation, anterior and posterior pouches are 70
It is represented by chi modulation. The zero level of the color (0) component is represented by 50 modulation, and the maximum or minimum level is 0 luminance (0) represented by 89 modulation and 11% modulation, respectively.
In the Y) component, the black level and white level are expressed by 80-column modulation and 20-column modulation, respectively.The modulation range of the 0-hull component and the luminance component is 1.8 between the maximum peak and peak amplitudes of these two components. Maintain a one-to-one relationship. The output signal of modulator 2q is applied to a vestigial sideband filter 29 to remove almost all of the lower sideband of the amplitude modulated carrier wave output from modulator 27. The output signal of filter 29 is applied to a first input terminal of adder circuit 80 .

The output terminal of the adder circuit 80 is the output terminal 81 of the conversion unit.
4G to the cable distribution system.

Output terminals B and 0 output the decompressed audio/data component and the second clock frequency (8,875 MH2), respectively.
is connected to digital modulator 82. Another input terminal of the digital modulator 8g receives the audio carrier from the second carrier oscillator 8B. The frequency of this audio carrier wave is higher than the frequency of the carrier wave obtained from the first carrier wave oscillator 28;
Digital modulator 82 also digitally modulates the audio carrier wave with the expanded audio/data component using, for example, quadrature digital phase modulation. The modulated audio carrier output is then applied to the second input terminal of the summing circuit 80 via a bandpass filter 84 so that it can be sent to the output terminal 81.

The frequency spectrum of the signal appearing at the output terminal 81 is
As shown in A1g, here the video carrier is denoted by VO,
The vestigial sideband spectrum of the video signal varies from about 1.25 Mn2 below the video carrier to about 8.5 Mn2 above the video carrier.
Extends to MH2. The audio carrier wave indicated by So is located at lIMMH2 above the video carrier wave VC, and the decompressed audio/data component extends over approximately 8MH2 around this audio wave. As is clear from FIG. 5A, The band of the modulated audio component is located outside the band of the modulated video component, and the bandwidth occupied by the modulated video component and the audio component together is approximately 14 Mn269, which is DBSO- This is approximately half the bandwidth of the MAO signal over 2.7 Mn2.

Instead of placing the oscillation frequency of the second carrier wave oscillator 88 above the oscillation frequency of the first carrier wave oscillator 28, the oscillation frequency of the second carrier wave oscillator 88 is placed below the oscillation frequency of the first carrier wave oscillator 28, i.e., the modulated first carrier wave remains. The lower part of the sideband can also be placed at
The frequency spectrum of the signal appearing at the output terminal 81 suitable for use with two adjacent cable television channels is shown in FIG. 5b, where the video carrier is designated VC and the vestigial sideband video The spectrum of the signal is about 1.5 mm below the video carrier. f26 M) 12 to approximately 13.5 Mi (2) above the video carrier. The audio carrier, denoted SC, is located 8.5 MH2 below the video carrier, and the decompressed audio/data components However, in this type of digital modulation, which extends over approximately 8 MB2 around the audio carrier, the frequency of the audio carrier is
0 is not located at the center of the data component spectrum
Figure 5C is the European standard (per channel? MB2
), which is similar to FIG. 5b, but where the vestigial sideband video signal is The audio carrier SO is located 2.85 MHz below the video carrier VC, extending from approximately I I12 below the carrier. For both British and European standards, the maximum amplitude of the voice/data signal can be of the order of -20 dB relative to the video carrier. The bandwidth of the component lies outside the bandwidth of the modulated video component, and the bandwidth occupied by the modulated video and audio components together is 14 MH2, which is 21 MH2 of the DBSO-MAO signal. (approximately half the bandwidth of 0-MAODBS) The processor 14 described in connection with FIG. In such a case, the synchronization pulse generator 28 is not necessary, and the synchronization separation circuit 22 supplies synchronization information to the receiver. It may also be similar to the conversion unit of Figure 2, in which case the output of the de-enfax stage 1z is connected to the necessary circuitry for demodulating the video component, and the outputs B and C of the processor 14 are connected to the audio/video component. Such video and audio/data circuits connect to the necessary circuitry for demodulating the data components.
Included in the figure. In such receivers, a total reduction in the bit rate for the audio/data component simplifies the operation of the associated demodulation circuit. /G or PA
1 is a block diagram of a television receiver capable of receiving television signals from a cable distribution system in either of the configurations L, -I. This television receiver has input terminals 85 suitable for connection to the cable system This input terminal 85 is connected to a tuner unit 86 which can cover the VHF and UHF frequency bands (40-860MH2).
It has a reception signal bandwidth of MB2. Tuning unit 86
The local oscillator of is connected to the connection line 8 in the same way as the tuning unit 5 of FIG. Tuning is achieved by a control voltage passing through the summing circuit 88 and the summing circuit 88. The tfcAFO signal is applied from connection 89 to the second input terminal of summing circuit 88.The nature of the IF signal emerging from tuning unit 46 depends on the signal being processed. However, for any type of signal, the IF multiple signal of the video carrier must be at the same frequency, for example 89.5 MHz if a receiver receives PAL-I and 89.5 MHz if the receiver receives PAL-B/G. is 88.9
M) I2. At this time, the intermediate frequency signal of the audio carrier wave is 8B, 5 MB2 in the case of the PAL-I signal, and the intermediate frequency signal in the case of the WAG signal is when the audio carrier wave SO is above the video carrier wave VC (Figure 5A). is 28.
6 M) f2 and the audio carrier SO is the video carrier v
When it is below O (FIG. 5B), it is 48 MHz. P
In the case of the AL-B/G signal, the intermediate frequency signal of the audio carrier is 88.4 MHzIc, and the intermediate frequency signal of the M0 signal is when the audio carrier SC is above the video carrier vO (
Figure 5A] is 87.9 MB2 and p1 audio carrier SC
is below the video carrier vCO (Fig. 5C), 41
．． 75 MHz. The output signal of the tuning unit 86 is amplified by the amplification stage 40, and the amplified output signal is applied to the first mode switch 41. In this first system switch 41, an incoming signal is applied to either the upper 11 (PAL) output terminal or the lower (MAC) output terminal. The PAL output terminal is connected to the first (PAL) bandpass filter 42, and its band characteristics are approximately as shown in FIG. 7Aa or 7Ba in the case of PAL-I, and
In the case of LB/G, the MAO output terminal of the 0 switch 41 is the second (MAO video) as shown in Figure 7ca.
It connects to bandpass filter 48 and eighth (MAO voice/data) bandpass filter 44 . The band characteristics of the filter 4B for a receiver that also receives PAL-I signals are as shown in FIG. 7Ab, that is, FIG. 7Bb, and that of the filter 48 for a receiver that also receives PAL-B/G signals. The band characteristic is the 7th
The band characteristic of the filter 44 for the receiver which also receives the oPALI signal as shown in Figure Cb is 7.
If the audio carrier SC is below the video carrier VC (FIG. 5B), the situation is as shown in FIG. 7BC. If the receiver also receives PAL-B/G signals and the audio carrier is below the video carrier (
5C), the band characteristic of the filter 44 is 'I OC'.
As shown in the figure. Bandpass filters 42, 413 and 44 are conveniently surface acoustic wave filters.

The output terminals of the first and second bandpass filters 42 and 48 are connected to the input terminal of an intermediate frequency amplification and detection stage 45. This I
F amplification/detection stage 45 is a Philips integrated circuit TDA 8
540 or TDA 3541 (the type chosen depends on the tuning unit 86), for which nevexopmen:r sa -mpl
e nata has been published. In addition to the integrated circuit amplification and detector stages, the IF detection and detection stage 45 includes an AFO voltage for the tuning unit 86 (which is placed on connection 89) and an automatic gain control (AGC) voltage (which is placed on connection 89). (loaded onto the connecting path 46). In this way A.G.O.
One reason for the generation of the voltage is that the pseudo sync pulse is inserted into the video signal (MA
O) (the PAL-I signal already contains a corresponding synchronization signal).

The detected output signal of the IF amplification/detection stage 45 is applied to a second scheme switch 42 which is similar to the first scheme switch 41 and operates in conjunction therewith. This second method switch 47
The upper (PAL) output terminal of the (PA
This PAL signal demodulator uses the luminance and chrominance subcarrier components to create a luminance signal Y' as well as a red difference signal (R-Y) and a blue difference signal CB-Y) when set to L operation. The structure and operation of is considered to be well known and need not be explained in detail.

The PAL output terminal of the second method switch 47 is connected to another band filter 49. The O band filter 49 is a
Mn2(PAL-I) or 5.5 Mn2(PAL-I)
B/G), which selects an intercarrier frequency modulated audio signal when a -PAL signal is present. This intercarrier FM audio signal is further processed and demodulated in an intercarrier audio stage 50, and its output is generates a demodulated audio signal on the side and provides it to a loudspeaker (not shown). The PAL output terminal of the second mode switch 47 is further connected to a sync separation stage 51 from which, when a PAL signal is present, a line sync pulse fH/ and a field sync pulse fv' are generated from the eighth bandpass filter 44. The output terminal of is connected to a regeneration stage 5z, where, when the MAO signal is present, a second clock frequency of 8.875 Mn2 (output terminal 58) and a continuous audio signal of 8.875 Mbit/S are output from the audio carrier IF. /
The output signals appearing at these output terminals for regenerating the data bit stream (output terminal 54) are applied to input terminals E and F of a unit 55 which produces clock signals, synchronization signals and control signals for processing the MAO signal. O added respectively
Details of this unit 55 are shown in FIG. 8, and as is clear from FIG. 8, the 8.875MH275Mn2 clock terminal E is connected to the first input terminal of the phase comparator 56. The input terminal of the input terminal divides the signal output from the frequency divider circuit 57, which divides the frequency of the applied signal by 2, into 8.8.
Receive at this clock frequency of 75 MHz. The output of the phase comparator 56 is a voltage that depends on the phase relationship between the two input signals, and this voltage is applied via a low-pass filter 58 to the control input terminal of a voltage-controlled crystal oscillator 59 with a frequency of 20.25 MH2. The output terminal of the 0 oscillator 59 is sequentially connected to the input terminal of the frequency dividing circuit 57 via a frequency dividing circuit 60 that divides the frequency by - and another frequency dividing circuit 61 that divides the frequency by 2.

Frequency dividing circuits 60, 61 and 57 are 18.5MH2, 6, respectively.
, 75MH7, and 8.875 M) (2S outputs, which are added to the control stage 62 together with the output of the oscillator 59.

An input signal coming in from input terminal F is also applied to this control stage 62. Another input terminal of control stage 62 receives the pseudo sync pulse coming from input terminal G. This pseudo-sync pulse present in the MAC video signal is separated from the signal present at the MAC output terminal of the second mode switch 47 by a pseudo-sync detector 68 whose output terminal is connected to the input terminal G (sixth figure). A control stage 62 outputs the timing signals necessary to process the MAO video signals, which are applied from output terminals H and 2 of unit 55 to multiple lead connections 64 and 64', and are suitably locked. The outputs of the control stage 62, including the frequency, are also applied to a sync generator 65 which produces from these inputs a line sync signal (fH) and a field sync signal (fv). is applied to output terminals J and K of unit 55.

The MAO output terminal of the second method switch 47 is analog -
Connect to digital converter 66. This A/D converter 6
6 also receives control signals coming from unit 55 on connection 64 and a clock signal of 20.25 MH2.
The time series video signal is converted to digital form by an A/D converter 66, and the parallel bits of the A/D converter 66 are sent on a multiple lead connection 67 to a MAO video processor 68 where the color components and The luminance components are stored and expanded individually in a known manner under the control of control and clock signals present in connection 64'. MAO video processor 68 has eight output terminals, and these eight output terminals are connected to respective digital-to-analog converters 6 as shown.
9.70 and 71, which are connected to low-pass filters 72.78 and 74, respectively, to output the luminance signal (Y).
and red difference signal (R-Y) and blue difference signal (B-Y)
e Output Y, R-Y and B-Y signals from the processed MAO signal and Y' from the processed PAL signal,
The (RY)' and (B-Y)' signals are applied to respective input terminals of another multipole switch 75. Is this a multi-pole switch? 5 also has synchronous signal technicians ff and f
H' and fv' are also added. This method switch H, V switch 7111 works in conjunction with the method switches 41 and 47. The 0 method switch 75 applies appropriate signals to the display unit 76 depending on the type of signal received. Processed in a known manner to produce a television display The clock frequency output terminal 5B of the playback stage 52 and the audio/data output terminal 54 are also connected to an audio/data decoder 77. This audio/data decoder 77 separates and demultiplexes the audio and data signals.

decoder? 7 details are not shown, but the structure is audio/
This is because it depends on the structure of the data components. decoder 77
The extracted audio signal is switched to switches 41 and 4? as well as? 5 is applied to the loudspeaker via another mode switch (not shown)' (i-).

As is apparent from FIG. 6, this dual standard receiver utilizes a number of elements that can be used in common no matter which signal is being received. In the above explanation, one of the two signals '1PA
Although it is of the L standard, it could alternatively be any form of frequency multiplexed color television signal.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of one line period of the C-MAO signal), Figure 2 is a schematic diagram of one line period of the C-MAO signal.
1 is a block diagram of a conversion unit used in the present invention. FIG. 8 is a detailed block diagram of a part of FIG.
Figure C is a schematic diagram of the frequency characteristics of the second signal of the present invention. Figure 6 is a block diagram of a television receiver used in the present invention. Figures A, 7B, and 7C are schematic diagrams of the bandpass characteristics of the filter used in the receiver of Figure 6, and Figure 8 is a block diagram showing a part of Figure 6 in detail.0 1... Parabolic antenna 2... Down converter unit 8... Coaxial cable 4... Input terminal 5... Tuning unit 6... Connection path 7... Adder circuit 8...
Connection path 9...Amplification stage 10...Surface acoustic wave filter 11.
...Limiter and discrimination stage 12...De-emphasis stage 1
8...Limiter and 2-4 PSK @Adjustment 14...
Audio/data processor 15...phase comparator 16...voltage controlled crystal oscillator (V(30)17...
Low-pass filter 18... Branch unit 19... Digital memory 20... Bit insertion stage 21... Bit generator 22... Synchronous separation circuit 28... Synchronous pulse generator 2, 6... - Synchronous insertion stage 27... Modulator '28... First carrier wave oscillator 20... Residual sideband filter 80... Addition circuit 81... Output terminal 82... Digital modulator 88.・Second carrier wave oscillator 84・
...Band filter 85...Input terminal 86...Tuning unit) 8? ... Connection path 88 ... Addition circuit 89
... Connection path 40 ... Amplification stage 41 ... First system switch 42 ... First bandpass filter 48 ... Second
Bandpass filter 44...Eighth bandpass filter 45...Intermediate frequency amplification/detection stage 46...Connection w! 47...Second method switch 48
... PAL signal demodulation circuit 49 ... bandpass filter 50
. . . Intercarrier audio stage 51 . . . Synchronization separation stage 52 . . . Reproduction stage 58, 54.
... Output terminal 55 ... Signal generation unit (unit) 56 ... Phase comparator 57 ... Branch circuit 58 ... Low-pass filter 59 ... Voltage-controlled crystal oscillator 60, 61 ... Frequency division Circuit 62... Control stage 68...
・Pseudo synchronous detector 64, 64'...multiple lead connection path 66...synchronous generator 66...A/D converter 67・
...Multiple lead connection path 68...MAO video processor 69, to, 71...D/A converter 75...
Multi-pole switch 76...display unit? ? ...Continued from page 1 of audio/data decoder 0 ■Int, CI,' Identification symbol Internal reference number H04N
11104 7423-5C priority claim 0198 25th Hu Qie month [phase] United Kingdom (GB) [phase] 831443
40 Inventor Bruce, Murray United Kingdom
Rich Court 10 Saraton Swicket Road Bar

Claims (1)

Claims: 1. A method of processing discrete lines of digital audio/data components of a time-multiplexed television signal, each line sequentially processing digital audio/data components of a first bit rate; a video component; separating said digital audio/data component from said television signal and decompressing said digital audio/data component to have a second bit rate; component occupies a significant portion of a discrete period, said period corresponding to the period of one line, said second focus speed being an integer fraction of said first focus speed, and said second bit d where fl is a first bit rate, n is the number of bits in the compressed audio/data component in said television signal, and m is the number of bits in one line period at said first bit rate. 1. A television signal processing method, characterized in that when expressed as a number, f is larger than x. λ A first time-multiplexed television signal having a predetermined bandwidth is used for transmitting a second time-multiplexed television signal over a medium whose bandwidth is limited relative to the bandwidth of this first television signal. The subdivided lines of the first television signal □ are converted into a television signal, and the subdivided lines of the first television signal □ are sequentially converted into digital audio/
a data component, a temporally compressed color component, and a temporally compressed luminance component, the audio/data component modulating a carrier wave at a first bit rate, and the carrier wave modulating the color component at a first bit rate; and a luminance component frequency modulated television transmission system, wherein the second television signal includes a first carrier wave amplitude-varied by a video signal, and wherein the individual lines of the video signal correspond sequentially to compression. a temporally compressed color component and a temporally compressed luminance component located at corresponding positions in said first television signal; The signal further includes a second carrier wave located outside the modulation wave of the second carrier wave, the second carrier wave being modulated by the digital voice/data component at a second bit rate, the discrete period of time being , - corresponding to a period of a line, comprising an audio/data component present in the individual lines of said first television signal, but stretched to occupy the majority of each individual period; has a bit rate that is an integer fractional multiple of said first bit rate, said second bit rate is such that fo is the bit rate of the compressed audio in said first television signal; /a number of points in a data component, and m is the number of bits in one line period at the first bit rate, which is greater than f×i. & The television transmission system according to claim 2, wherein the modulation of the first carrier wave by the video signal is vestigial sideband amplitude modulation. 4. The television transmission system according to claim 3, wherein the second carrier wave is located on a sideband of the modulated first carrier wave. 5 additionally present a pulse signal on each line of the video signal of said second television signal, placing said pulse signal in a position corresponding to the position of the audio/data component in said first television signal; A television transmission system according to claim 2, 8, or 4, characterized in that: 6. The television signal processing method or television transmission system according to any of the preceding claims, wherein the fraction of the integer is less than or equal to i. ? 7. The television signal processing method or television transmission system according to claim 6, wherein the second bit rate is set to 7 of the first t/) bit rate. 8. A method of processing a television signal according to any of the preceding claims, characterized in that an additional digital component is added to the decompressed audio/data component in a small portion of each individual period. or television transmission system. 9. Said additional digital component may generate additional audio/digital components.
Claim 8, characterized in that it carries data information.
2. The television signal processing method or television transmission system according to paragraph 1. 1G, an apparatus for use in the television signal processing method according to any one of claims 1, 6, 7, 8 or 9, wherein the individual lines are sequentially and means for reproducing the digital audio/data component from the television signal. decompresses the reproduced audio/data component at a second bit rate such that the reproduced component from each line of said first television signal is... additionally comprising means for occupying the second
is an integer fractional multiple of the bit rate of il,
This second bit rate makes fo the first bit rate,
greater than f, x-, where n is the number of bits in the audio/data component in the first television signal and m is the number of bits in a line period at the first bit rate. A device characterized by: 11 For use in the television transmission system according to any one of claims 2 to 9,
means for receiving the first television signal, wherein the individual lines of the television signal sequentially include a digital audio/data component, a temporally compressed color component, and a temporally compressed color component; means for modulating a carrier wave with said digital/audio component at a first bit rate and frequency modulating said modulated carrier wave with said compressed color and luminance components; a converting unit comprising: means for frequency demodulating the modulated carrier wave to produce said compressed color and luminance components; and means for reproducing digital audio/data components from said modulated carrier wave; amplitude modulating the compressed chrominance and luminance components demodulated to correspond to the compression ratio and position of these components on the first carrier wave with the compression ratio and position of the television signal in the first carrier wave; means for decompressing the reproduced audio/data component at a second bit rate, such that the reproduced component from each line of said first television signal is separated into individual segments corresponding to the duration of one television line; the second bit rate is an integer fraction of the first bit rate, and the second bit rate is fo the second bit rate.
σ) where f is the focus speed, n is the number of bits in the audio/data component in said first television signal, and m'ft is the number of bits in one line period at the first bit rate. , x, and means for modulating the decompressed audio/data component onto a second carrier outside the modulation of the first carrier, A conversion unit characterized in that two modulated carrier waves form a second television signal. 1λ The conversion unit is additionally provided with a vestigial sideband filter, and the first carrier wave is configured to amplitude modulate the vestigial sideband with the compressed color and luminance components. The conversion unit according to item 11. 1 & the conversion unit converts the second carrier into the first
13. The conversion unit according to claim 12, further comprising means for placing and positioning the carrier wave on a residual side wave band stop of the carrier wave. 14 means for the converter unit to further generate a pulse signal at line rate; and for adding the pulse signal to the video signal of the second television signal; Claims 11, 2 or 18, characterized in that the method comprises means for causing the component to fall within a position corresponding to the position of the component.
Conversion unit 14 according to claim 14, characterized in that said device or conversion unit additionally comprises means for adding a digital component to said decompressed digital audio/data component in a fraction of each individual period. range 1
The device or conversion unit according to any one of Items 0, 11, 12, 18, or 14. 16. The apparatus or conversion unit of claim 15, wherein the apparatus or conversion unit further modulates the added digital component with audio/data information. 1'F, for use in a television transmission system according to claims 2 to 9, connected to a transmission medium with limited bandwidth and selecting one from several transmission channels; A television receiver comprising: a first signal processing circuit connected to the selection means for processing a video signal carried by the first carrier; In particular, the second
a second signal processing circuit for processing audio/data information carried by a carrier wave, the second signal processing circuit converting a second bit rate present in the second television signal to a second bit rate present in the second television signal; A television receiver, characterized in that it comprises means for regenerating a clock signal corresponding to a first bit rate present in a television signal. 18. means for generating a timing signal for the receiver to additionally process color and luminance components present in the video signal, the timing signal being generated from information contained in the audio/data component; and means for applying the regenerated pulse signal to the processing means such that a predetermined time relationship exists between the pulse signal and the upper timing signal. A television receiver according to claim 17, which is dependent on characteristic claim 5. 19. In the television receiver according to claim 17 or claim 18, which is dependent on claim 5, the selection means is subject to automatic gain control. A television receiver characterized in that it is configured to be derived from a pulse signal present in a video signal. 20. Claims 17 and 18, characterized in that the television receiver is a dual standard receiver capable of receiving both the second television signal and a frequency-multiplexed television signal. 9. Television receiver according to any one of item 9 +11. 21. A television receiver according to claim 20, in which even different standard signals can be applied to the same intermediate frequency amplifier and the same demodulation circuit, wherein a switchable filter is provided and operated together with the intermediate frequency amplifier. , a television receiver configured to produce the necessary band characteristics for a signal of an appropriate standard.