JP2007013453A - Signal input device, signal output device, signal input/output device and status monitoring device for wheel using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for superimposing a plurality of signals respectively showing two statuses as a logical signal independently of the status of any of those signals, and for transmitting information in a plurality of signals in a restorable state with a few signal lines. <P>SOLUTION: A signal input device superimposes a plurality of signals S1 and S2 shaped like rectangular waves having different amplitudes respectively showing two statues as a logical signal, and generates a step-shaped signal SS showing the status of n-th power of 2 according to a signal level by using the total number of a plurality of signals as n. A signal output device is provided with a comparing part for deciding the signal level from such types of thresholds TH1, TH2 and TH3 calculated by subtracting 1 from the n-th power of 2 by using the total number of the plurality of signals as n and a decode part for reproducing two statues respectively shown by the plurality of signals S1 and S2 based on the decision result of the comparing part. This signal input/output device is configured of the signal output device and the signal input device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a signal output device that superimposes and outputs a plurality of signals each representing two states without losing information of each signal. The present invention also relates to a signal input device that reproduces a state represented by a plurality of original signals from a signal in which a plurality of signals each representing two states are superimposed. The present invention also relates to a signal input / output device including such a signal output device and a signal input device. Furthermore, the present invention relates to a wheel state monitoring device provided with such a signal input / output device.

  As a signal input device, a signal output device, and a signal input / output device as described above, Patent Document 1 shown below is applicable to a wheel state monitoring device including a wheel rotation detection device and brake lining wear. Technology is shown. This relates to an information superimposing method in which information included in each signal is represented on one signal by superimposing these signals. According to this technique, one signal has two predetermined levels (High and Low), and is a signal that represents information by an analog period change of the two levels (Patent Document 1). It is called an analog signal.) The other signal includes a digital signal that represents information in the form of a digital data word. The superimposing unit causes the digital data word to exist at the beginning of the high state of the analog signal that represents the rotation speed by the period. In other words, the duty ratio of an analog signal having two predetermined levels is changed from 1: 1 to 3: 7, 7: 3, etc., and a part of the higher level (for example, 7 to 7) Is used to represent a digital data word. According to Patent Document 1, when the maximum rotation speed frequency is 3 kHz, it is possible to take a maximum data word length of about 100 microseconds at a duty ratio of 30 to 70% that is possible from now.

  Further, Patent Document 2 shown below describes a detection signal output method of a rotation sensor that can output not only the rotation speed (rotation frequency) but also information such as the rotation direction and self-diagnosis result, and this method. The technique of the detection signal processing apparatus used is shown. In this technique, information different from the rotation speed such as the rotation direction is output at a timing corresponding to the rotation speed. That is, using two pulses having different pulse widths, these pulses correspond to logical values “1” and “0”, respectively, and are output at a timing according to the rotation speed. The output speed represents the rotation speed, and the pulse width represents, for example, forward rotation when the logical value is “1” and reverse rotation when the logical value is “0”. Here, in a state where the rotating body starts to rotate in the forward direction or the reverse direction and the rotational speed exceeds a predetermined speed, the rotational direction does not change abruptly. Therefore, if the speed exceeds a predetermined speed, it can be considered that the same rotational direction can be maintained without indicating the rotational direction. Then, the pulse width of the waveform indicating the rotation direction in the forward direction and the reverse direction is made to correspond to the data code of logical values “1” and “0”, and the digital information such as the self-diagnosis result is obtained at a timing according to the rotation speed. I am trying to output.

JP-A-10-70524 (paragraphs 2-16, 43-50, FIGS. 4, 7) JP 2001-165951 A (8th to 10th paragraphs, FIGS. 7 to 12)

  The techniques described in Patent Documents 1 and 2 have a simple configuration and can superimpose signals representing two or more pieces of information on one signal. However, in the technique described in Patent Document 1, when the period of the analog signal is shortened (for example, when the rotating body rotates at a high speed), the pulse interval becomes narrow and other information (digital data word) is sufficiently superimposed. It may not be possible. In the techniques of Patent Document 1 and Patent Document 2, other information is superimposed in synchronization with the pulse of one signal such as a signal indicating the rotational speed of the rotating body. Therefore, in a situation where the pulse of one signal is not output, the other information cannot be superimposed. That is, both the techniques described in Patent Document 1 and Patent Document 2 have a problem that whether or not other information can be superimposed depends on the state of one signal.

  The present invention has been made in view of the above-described problems. A plurality of signals each representing two states as logic signals are overlapped without depending on the state of any of the signals, and the number of signal lines is reduced. An object of the present invention is to provide a technique capable of transmitting information contained in a plurality of signals in a recoverable state.

  In order to achieve this object, the signal output device according to the present invention is characterized in that each signal represents two states as logic signals and superimposes a plurality of rectangular wave signals having different amplitudes, and the plurality of signals Is a point-like signal that represents the state of 2 n according to the signal level of the superimposed signal.

  Each signal before superimposition is a signal (logic signal) representing two states according to the respective signal levels. According to this characteristic configuration, the signal after the superimposition of these signals is a stepped signal having a signal level of 2 n, where n is the total number of signals. For example, if the total number of signals is 2, the signal has four signal levels, and if the total number of signals is 3, the signal has eight signal levels. Therefore, it is possible to superimpose a plurality of signals on one signal without damaging the information possessed by each original signal. Further, it is not necessary to synchronize with any one of the plurality of signals, and each signal can be superimposed on one signal while maintaining independence. As a result, it is possible to provide a signal output device that can transmit information included in a plurality of signals through a small number of signal lines.

  In addition, when superimposing each signal by adding each amplitude, if each signal is a voltage output signal, an addition circuit using an active element such as a transistor or an operational amplifier is required. However, if each signal is a current output signal, such an addition circuit is not necessary. That is, by short-circuiting the signal line of each signal to one signal line, the current value of each signal is added according to Kirchhoff's law. Therefore, if the plurality of signals before superposition are current output signals, it is possible to superimpose the plurality of signals with a small circuit scale.

  Preferably, the total number of the plurality of signals is 2, and the amplitude of one of these two signals is 40% to 60% of the amplitude of the other signal.

  If the amplitude of any one of a plurality of signals is the same as the sum of the amplitudes of the other two or more signals, or is extremely close to being difficult to distinguish, the signal after superimposition is the signal before superimposition. It is not possible to clearly distinguish the state of 2 to the nth power, where n is the total number of. The same applies to the relationship between the sum of any two or more amplitudes in a plurality of signals before superposition and the sum of the amplitudes of the other two or more signals. When the signal that can be clearly distinguished is less than 2 to the nth power in the signal after superimposition, the information that the original signal has partially overlaps. That is, as a result, the information amount is lost in the superimposed signal. If the amount of information is lost in this way, the value of using the superimposed signal is significantly reduced even if it can be superimposed on one signal. Accordingly, the sum of any two or more amplitudes in the plurality of signals before superposition is different from the sum of the amplitudes of the other two or more signals and the amplitude of any one of the other signals. Good.

  When the sum of a plurality of signals is 2, as described above, if the amplitude of one signal is 40% or more and 60% or less, more preferably about 50% of the other amplitude, The distinction of the state (2 squared = 4) becomes clear. For example, when the amplitude of one signal (M) is 50% of the amplitude of the other signal (N), the four states (signal levels) of the superimposed signal are as follows. The lowest level is when the amplitude of both signals is low, and the next lowest level is 50% of the amplitude of signal (N) when signal (M) is high and signal (N) is low. . The next lowest level is 100% of the amplitude of signal 2 when signal (M) is low and signal (N) is high. The highest level is 150% of the amplitude of the signal (N) when the amplitudes of both signals are both high. In this way, the levels of the superimposed signal are equal with 50% of the amplitude of the signal (N) as a difference. As a result, it is possible to obtain a signal that can satisfactorily transmit information included in a plurality of signals by a single signal.

When the total number of the plurality of signals is 3 or more, the relationship that the amplitude of one of the two signals among the plurality of signals is 40% or more and 60% or less of the amplitude of the other signal is described above. It is preferable that all signals are satisfied with respect to any signal without overlapping among the plurality of signals.
Furthermore, the relationship that the amplitude of one of the two signals among the plurality of signals is within + − (plus or minus) m with respect to 50% of the amplitude of the other signal is It is preferred that all signals are satisfied for any signal without being duplicated in them. The value of m is preferably 1/3 or less of the minimum amplitude of the plurality of signals, and further 1 / (2n-1) or less with respect to the total number n of signals.

  Further, the signal input device according to the present invention is characterized in that each signal level is represented by a staircase-like signal in which each signal represents two states depending on the signal level and a plurality of rectangular wave signals having different amplitudes are superimposed on each other. Is represented by a threshold value which is a value obtained by subtracting 1 from 2 to the nth power, and the plurality of signals are represented by 2 based on the determination result of the comparison unit, respectively. And a decoding unit that reproduces one state.

  As described above, each signal represents two states depending on the signal level, and a stepped signal in which a plurality of rectangular wave signals having different amplitudes are superimposed is a signal of 2 n power, where n is the total number of the plurality of signals. Has a level. Therefore, by setting a threshold value of a type obtained by subtracting 1 from 2 n to each signal level of 2 n types, it is possible to specify all the signal levels of 2 n types. it can. Each signal level specifies a unique one of combinations of signal levels of a plurality of signals before superposition. Therefore, if the signal level can be specified, the signal level of each signal before superposition can be reproduced.

  When the plurality of signals and the stepped signal are current output signals, the signal input device needs to include a current detection circuit in order to determine each signal level of the current output signal. In this case, the signal input device may be provided with a current-voltage converter that converts the current output signal into a voltage output signal. When the current output signal is converted into the voltage output signal, the comparison unit can make a determination based on the threshold value set by the voltage value. That is, the comparison unit can be easily configured using a general-purpose comparator or the like. It is also possible to perform comparison and determination by digitally converting the superimposed signal using an A / D converter or the like and calculating using a microcomputer or the like.

  In addition, a rotation is provided that includes a signal input / output device having a signal output device and a signal input device according to the present invention, and outputs a rotation detection signal in the form of a rectangular wave to the plurality of signals at a frequency according to the rotation speed of a vehicle wheel. It is preferable that a wheel state monitoring device including an output signal of the sensor and a rectangular wave signal representing information on the air pressure of the wheel is configured.

  The signal input / output device according to the present invention reproduces information that a plurality of original signals have from a signal output device that successfully superimposes a plurality of signals on one signal and a signal that is superimposed on one signal. And a signal input device. Therefore, as described above, it is possible to configure a signal input / output device capable of transmitting information while minimizing the wiring between the signal output device and the signal input device. Further, as described above, the amount of information is not lost between input / output devices, and it does not depend on the state of any one signal.

  The rotation detection signal of the rotation sensor is output at a frequency corresponding to the rotation of the rotating body. Therefore, when the rotating body rotates at a high speed, the output frequency of the rotation detection signal increases. Therefore, if signals having other information are superimposed in synchronization with the output frequency of the rotation detection signal, a section in which other signals are superimposed may not be ensured when the output frequency is high. On the other hand, when the rotating body rotates at a low speed including the stop, the output frequency of the rotation detection signal is low. Further, when the rotating body is very slow, information on other signals cannot be transmitted quickly. Furthermore, no transmission is possible when the rotating body is stopped.

  Wheel pressure cannot be measured while the wheel is rotating. Therefore, in the method of transmitting air pressure measurement information in synchronization with the rotation detection signal of the rotating body, the air pressure is measured when the wheel is stopped, and the air pressure information measured after the wheel starts rotating is superimposed. For this reason, information on air pressure cannot be transmitted quickly. However, as described above, the wheel state monitoring apparatus of the present invention can superimpose the air pressure measurement information without depending on the presence or absence of the output of the rotation detection signal. As a result, it is possible to configure a wheel state monitoring apparatus capable of transmitting information satisfactorily.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a waveform diagram showing an example in which two rectangular wave (pulse-like) signals having different amplitudes are superposed according to the embodiment of the present invention. As shown in the figure, the first pulse signal S1 and the second pulse signal S2 are rectangular wave signals each having two states as logic signals and having different amplitudes. The superimposed signal SS (SS2) is a signal obtained by superimposing the first pulse signal S1 and the second pulse signal S2.

  The second pulse signal S2 has two states (signal levels) of a high level (hereinafter referred to as H level) H2 and a low level (hereinafter referred to as L level) L2 in the period A and the period B of one cycle of the signal. is doing. Manchester where the first half is H level and the second half is L level as in section A, and the first half is L level and the second half is H level as in section B Manchester which represents data "1" A code represents information.

  In the section X, the first pulse signal S1 has two states, ie, an H level H1 and an L level L1 as logic signals. Information is expressed by the period of the pulse signal. In the section Y, the case where a pulse-like signal does not exist is shown. For example, it can be said that the section X is a section in which a certain event is detected, and the section Y is a section in which a certain event does not occur.

  The superimposed signal SS is a signal obtained by superimposing the first pulse signal S1 and the second pulse signal S2 having different amplitudes, and has a stepped shape having four signal levels HH, HL, LH, and LL. Signal. These four signal levels will be described in detail with reference to FIG.

  FIG. 2 is a waveform diagram for explaining the basic principle of superposing two rectangular wave signals having different amplitudes. As in FIG. 1, the first pulse signal S1 has two states of an H level H1 and an L level L1, and is a rectangular wave with an amplitude P1. Similarly, the second pulse signal S2 has an H level H2 and an L level L2, and is a rectangular wave with an amplitude P2. Here, the amplitude of any one of the first pulse signal and the second pulse signal satisfies a relationship in which any one amplitude is between 40 to 60% of the other amplitude. In the principle diagram shown in FIG. 2, the amplitude of the second pulse signal S2 is 50% of the amplitude of the first pulse signal P1.

When the amplitude P1 of the first pulse signal S1 and the amplitude P2 of the second pulse signal S2 are as described above, a superimposed waveform SS2 (SS) in which the first pulse signal S1 and the second pulse signal P2 are superimposed. Is a stepped waveform having four signal levels as shown in FIG. The four signal levels are a first level LL, a second level LH, a third level HL, and a fourth level HH.
The first level LL is the sum of the L level L1 of the first pulse signal S1 and the L level L2 of the second pulse signal S2. The second level LH is the sum of the L level L1 of the first pulse signal S1 and the H level H2 of the second pulse signal S2. The third level HL is the sum of the H level H1 of the first pulse signal S1 and the L level L2 of the second pulse signal S2. The fourth level HH is the sum of the H level H1 of the first pulse signal S1 and the H level H2 of the second pulse signal S2.

  As described above, the amplitude P2 of the second pulse signal S2 is 50% of the amplitude P1 of the first pulse signal S1. The second amplitude SR2 of the superimposed signal SS2, which is the difference between the second level LH and the third level HL, is substantially equal to the amplitude P2 of the second pulse signal S2. Further, the third amplitude SR3 of the superimposed signal SS2, which is the difference between the third level HL and the fourth level HH, is substantially equal to the amplitude P2 of the second pulse signal S2. The first amplitude SR1 of the superimposed signal SS2, which is the difference between the first level LL and the second level LH, is the amplitude P2 itself of the second pulse signal S2. Thus, the maximum amplitude PS2 of the superimposed signal SS2 is substantially divided into three equal parts by the amplitude P2 of the second pulse signal S2. In order to determine whether the signal level of the superimposed signal SS2 is from the first level to the fourth level, the threshold value is within the respective ranges of the first amplitude SR1, the second amplitude SR2, and the third amplitude SR3. A value should be set. That is, as shown in FIG. 2, the first threshold value TH1 is set to the approximate median value of the first amplitude SR1, the approximately median value of the second amplitude SR2 is set to the approximately approximate median value of the second threshold value TH2, and the third amplitude SR3. The third threshold value TH3 may be set. As described above, since the amplitudes of the first to third amplitudes SR1 to SR3 are equal, the threshold value can be set satisfactorily. As described above, when two rectangular wave signals having different amplitudes are superimposed, if one amplitude is 50% of the other amplitude (a range of 40% to 60%), the superimposed signal is used. It is possible to obtain a superimposed signal that can smoothly determine the signal level of the.

As described above, the four signal levels of the superimposed signal SS2 are determined by the three threshold values TH1 to TH3 as follows.
When the signal level of SS2 is less than TH1: First level LL
When the signal level of SS2 is greater than or equal to TH1 and less than TH2: second level LH
When the signal level of SS2 is more than TH2 and less than TH3: Third level HL
When the signal level of SS2 is TH3 or higher: Fourth level HH
And the logical value of the information which the 1st pulse signal S1 had is determined as follows corresponding to the signal level of superposition signal SS2.
In the case of the first level LL and the second level LH: 0 (L1)
For 3rd level HL and 4th level HH: 1 (H1)
Further, the logical value of the information that the second pulse signal S2 has is as follows.
For the first level LL and the third level HL: 0 (L2)
For the second level LH and the fourth level HH: 1 (H2)
In this way, it is possible to extract information possessed by the original rectangular wave signal from the superimposed signal SS2.

  When the level of the output signal is large or when the signal analysis can be performed with high accuracy even when the level of the output signal is small, the amplitude of one signal is in the range of 40 to 60% of the amplitude of the other signal. The present invention is applicable without being limited to this relationship. In the waveform example shown in FIG. 3, the amplitude of one signal is 75% of the amplitude of the other signal. In this case, as shown in FIG. 3, the first amplitude SR10 and the third amplitude SR30 are large amplitudes, but the second amplitude SR20 is much smaller than the first amplitude SR10 and the third amplitude SR30. Amplitude. As a result, the first amplitude SR10 and the third amplitude SR30 can easily set the threshold TH10 and the threshold TH30 within the range, but the second amplitude SR20 can easily set the threshold TH20. is not. Therefore, in comparison with the waveform example shown in FIG. 2, in the waveform example shown in FIG. 3, it is generally not easy to extract information included in the original rectangular wave signal from the superimposed signal SS20. . However, even in this case, if the level of the output signal is large, even if the amplitude of the second amplitude SR20 is relatively narrow, the threshold value TH20 can be sufficiently set as the absolute amplitude. There may be. Even when the absolute value of the second amplitude SR20 is narrow, the threshold value TH20 may be sufficiently set if the signal analysis can be performed with high accuracy.

  In the foregoing, the principle has been described in which each signal represents two states depending on the signal level and two rectangular wave signals having different amplitudes are superimposed to generate a stepped signal representing the four states depending on the signal level. This is not limited to the case where two signals are superimposed, but can also be applied to a case where a plurality of arbitrary signals are superimposed. That is, each signal represents two states depending on the signal level, and a plurality of rectangular wave signals having different amplitudes can be superimposed to generate a stepped signal representing a 2 n state. Here, n is the total number of a plurality of rectangular wave signals having different amplitudes. Moreover, if the amplitude of any one of the plurality of signals is different from the sum of the amplitudes of the other two or more signals, a preferable superimposed signal can be obtained. This basic principle will be described with reference to FIG. 4, which is an example in which each signal represents two states depending on the signal level and three rectangular wave signals having different amplitudes are superimposed.

  About 1st pulse signal S1 and 2nd pulse signal S2, it is the same as that of FIG.1 and FIG.2. In the basic principle shown in FIG. 4, the third pulse signal S3 is added to this and the three signals are superimposed to obtain a superimposed signal SS3. The third pulse signal S3 is a rectangular wave signal having an amplitude P3 that is twice the amplitude P1 of the first pulse signal S1. Accordingly, the amplitude P1 of the first pulse signal S1 is 50% of the amplitude P3 of the third pulse signal S3. Since the amplitude P2 of the second pulse signal S2 is 50% of the amplitude P1 of the first pulse signal S1, the three rectangular wave signals have different amplitudes. The sum of the amplitudes of any two signals of the three rectangular wave signals is different from the other one. For example, the sum of the amplitude P1 and the amplitude P2 is not equal to the amplitude P3. For other combinations, the sum of the amplitudes of any two signals is different from the other one. Further, the relationship that the amplitude of one of the two signals among the plurality of signals is 40% or more and 60% or less of the amplitude of the other signal does not overlap among the plurality of signals and It can be said that the signal is satisfied with any signal.

When the three signals have such a relationship, a stepped superimposed signal SS3 having a signal level of 2 to the cube is obtained as shown in FIG. As shown in FIG. 3, the superimposition signal SS3 divides the maximum amplitude PS3 of the superposition signal SS3 by 7 (= 2 ³ −1) equally by the width of the amplitude P2 of the second pulse signal S2, and the first amplitude SR1 to the seventh amplitude. It has SR7. Then, by setting the first threshold value TH1 to the seventh threshold value TH7 within the range of the first amplitude SR1 to the seventh amplitude SR7, respectively, the signal levels of the three signals before being superimposed are reproduced. Is possible.

As described above, the eight signal levels of the superimposed signal SS3 are determined by the seven (= 2 ³ −1) thresholds TH1 to TH7 as follows.
When the signal level of SS3 is less than TH1: First level LLL
When the signal level of SS3 is greater than or equal to TH1 and less than TH2: second level LLH
When the signal level of SS3 is greater than or equal to TH2 and less than TH3: third level LHL
When the signal level of SS3 is greater than or equal to TH3 and less than TH4: fourth level LHH
When the signal level of SS3 is greater than or equal to TH4 and less than TH5: fifth level HLL
When the signal level of SS3 is greater than or equal to TH5 and less than TH6: sixth level HLH
When the signal level of SS3 is greater than or equal to TH6 and less than TH7: the seventh level HHL
When the signal level of SS3 is TH7 or higher: Eighth level HHH
And the logical value of the information which the 1st pulse signal S1 had is determined as follows corresponding to the signal level of superposition signal SS3.
1st, 2nd, 5th, 6th level LLL, LLH, HLL, HLH: 0 (L1)
Third, fourth, seventh and eighth levels LHL, LHH, HHL, HHH: 1 (H1)
Further, the logical value of the information that the second pulse signal S2 has is as follows.
1st, 3rd, 5th, 7th level LLL, LHL, HLL, HHL: 0 (L2)
Second, fourth, sixth and eighth levels LLH, LHH, HLH, HHH: 1 (H2)
Further, the logical value of the information that the third pulse signal S3 has is as follows.
1st, 2nd, 3rd, 4th level LLL, LLH, LHL, LHH: 0 (L3)
Second, fourth, sixth and eighth levels HLL, HLH, HHL, HHH: 1 (H3)
In this way, it is possible to take out the information that each of the rectangular wave signals before being superposed well from the superposed signal SS3.

(Signal output device)
FIG. 5 is a schematic block diagram showing the configuration principle of the signal output apparatus 10 according to the present invention. This principle diagram shows a case where three signals are superimposed. That is, the first pulse signal S1, the second pulse signal S2, and the third pulse signal S3 are superimposed on each other by the signal superimposing means 18. And it is output from the signal superimposing means 18 as a superimposed signal SS. When these plural pulse signals are voltage output signals, the plural signals can be superimposed on each other by configuring the signal superimposing means 18 by an adding circuit using an operational amplifier or the like.

  When a plurality of signals are current output signals, the signals can be superimposed without using the adder circuit as described above. As shown in FIG. 6, by connecting each signal line at a connection point Q, the currents possessed by each signal can be added. According to Kirchhoff's law, the sum of currents flowing into one point (connection point Q) is equal to the sum of currents flowing out from one point (connection point Q). Therefore, the sum of the currents that flow from the first, second, and third pulse signals S1, S2, and S3 to the connection point Q is equal to the current that flows from the connection point Q to the superimposed signal SS. As a result, a plurality of signals, each of which is a current output signal, are superimposed on each other by connecting each signal at a connection point Q. Since the current output signal is a high impedance output, it is easily affected by external noise. Therefore, as shown in FIG. 7, the superimposed signal SS may be output after voltage conversion by the current-voltage converter 19. The superposed signal SS_V converted into the voltage output signal becomes a low impedance output, and the resistance against external noise received on the transmission line after output can be increased. In the voltage conversion by the current-voltage conversion unit 19 illustrated in FIG. 7, the voltage value of the superimposed signal SS_V after conversion is Vref−R × I, where I is the current value of the superimposed signal SS. Further, as shown in FIG. 8, a current-voltage conversion unit 29 may be provided in the signal input device 20 that receives the superimposed signal SS and reproduces information that the signal on the original rectangular wave has.

[Signal input device]
Hereinafter, a method for reproducing the information of the original rectangular wave signal from the superimposed signal SS (SS2, SS3, SS_V) superimposed as described above will be described. FIG. 9 is a waveform diagram showing an example in which information of the original rectangular wave shape is reproduced from a signal (see FIG. 1) in which two rectangular wave signals having different amplitudes are superimposed by the implementation of the present invention. is there. 10 and 11 are configuration examples of a signal input device that reproduces information included in the first pulse signal S1 and the second pulse signal S2 from the superimposed signal SS2 (SS, SS_V). In the configuration examples shown in FIGS. 10 and 11, for ease of explanation, the superimposed signal SS is a voltage output signal that has passed through the current-voltage conversion unit 19 or 29. The technical idea is the same even when the superimposed signal SS is a current output signal.

The comparison unit 21 shown in FIGS. 10 and 11 includes comparators 21a, 21b, and 21c that use threshold values TH1, TH2, and TH3 as reference voltages in order to determine the signal level of the superimposed signal SS. In the example shown in FIG. 9, the superimposed signal SS, since the two signals are superimposed, 2 ^two (= four) signal level LL of, LH, HL, and a HH. Accordingly, each signal level is determined based on 2 ² −1 types (= 3 types) of thresholds TH1, TH2, and TH3. The determination output c3 shown in FIGS. 9 to 11 is an output of the comparator 21c, and outputs an H level when the signal level of the superimposed signal SS is equal to or higher than the third threshold value TH3. The determination output c2 is an output of the comparator 21b, and outputs an H level when the superimposed signal SS is equal to or higher than the second threshold value TH2. The determination output c1 is an output of the comparator 21a, and outputs an H level when the superimposed signal SS is equal to or higher than the first threshold value TH1.

  The rectangular wave signal before being superimposed represents two states depending on the signal level. In other words, information is represented by a logical value with “1” when the signal level is H level and “0” when the signal level is L level. As is apparent from FIG. 9, the logical value indicated by the determination output c2 is the same as that of the first pulse signal S1. The first pulse signal S1 and the determination output c2 are different signals, such that one is a current output and the other is a voltage output, or the signal level is different even if both are voltage output signals. There are many. However, the information represented by the first pulse signal S1 and the determination output c2, that is, the logical values represented by both signals are the same. Therefore, the determination output c2 is a decoded signal d1 that reproduces the information represented by the first pulse signal S1.

  On the other hand, the logical value of the decode signal d2 that reproduces the information represented by the second pulse signal S2 is not the same as any one of the logical values of the determination outputs of the comparators 21a to 21c as in the decode signal d1. Absent. The determination output c3 of the comparator 21c shows a case where the first pulse signal S1 is at the H level and the second pulse signal S2 is at the H level. The determination output c1 of the comparator 21a indicates that the first pulse signal S1 is at the H level or the second pulse signal S2 is at the H level regardless of the signal level of the first pulse signal S1. . The state of the signal level of the first pulse signal S1 and the signal level of the second pulse signal S2 change independently. Accordingly, not all the states in which the second pulse signal S2 is at the H level can be extracted by only the determination output c3. The determination output c1 is mixed with two states that the second pulse signal S2 is at H level and the first pulse signal S1 is at H level. Therefore, in the decoding unit 22 shown in FIG. 10 and FIG. 11, the state of the signal level that the second pulse signal S2 had before being superimposed is reproduced from the determination outputs c1 to c3.

  In the configuration example of the signal input device 20 illustrated in FIG. 10, the decoding unit 22 includes a multiplexer 22 a. Then, either the determination output c3 or the determination output c1 is selected according to the logical value of the determination output c2, and is output as the decode signal d2. That is, when the determination output c2 is at the H level, the determination output c3 is set as the decode signal d2. When the determination output c2 is at the L level, the determination output c1 is set as the decode signal d2. By doing in this way, only the state of the signal level that the second pulse signal S2 before superimposition had is reproduced.

  Further, instead of the multiplexer 22a of the decoding unit 22, a logic circuit may be used as shown in FIG. When the logic circuit shown in FIG. 11 is used, the decode signal d0 is obtained by the determination outputs c2 and c1. Specifically, a case where the first pulse signal S1 is at the L level and the second pulse signal S2 is at the H level by taking the logical product of the inverted logic of the determination output c2 and the determination output c1 is shown. A decode signal d0 is obtained. The determination output c3 indicates a case where the first pulse signal S1 is at the H level and the second pulse signal S2 is at the H level as described above. Therefore, when the logical sum of the decoded signal d0 and the determination output c3 is taken (decoded signal d2), the information (logical value) of the second pulse signal S2 is removed by eliminating the influence of the signal level of the first pulse signal S1. Can be reproduced.

  As shown in FIG. 9, the second pulse signal S2 and the decode signal d2 may be different in current output and voltage output, or may have different signal levels even if both are voltage output signals. . However, the information represented by the second pulse signal S2 and the decode signal d2, that is, the logical values represented by both signals are in good agreement. As shown in FIG. 9, the logical values indicated by the waveforms of both signals are the same, and the logical values of the data converted into Manchester code by the waveforms are also the same. Therefore, it can be said that the decode signal d2 reproduces the information represented by the second pulse signal S2 satisfactorily.

  Further, the signal input device 20 may be configured as shown in FIG. FIG. 12 shows an example in which the superimposed signal SS after passing through the current-voltage conversion unit 19 (29) is analyzed (determination and information restoration) using a processor such as a microcomputer. In this configuration example, the superimposed signal SS is converted into a multi-bit digital value by the A / D converter 23. The threshold value for determining each signal level of the superimposed signal SS is stored in the register 24 as a digital value. The comparison unit 21 compares the threshold value stored in the register 24 with the digital value of the digitally converted superimposed signal SS. Based on the comparison result of the comparison unit 21, the decoding unit 22 reproduces information included in the signal before superimposition. Note that each unit shown in FIG. 12 shows division as a function, and each unit does not need to be physically independent. You may implement | achieve by the software which has each function on the same hardware. Further, the comparison unit 21 and the decoding unit 22 may be configured by one microcomputer. In this case, the comparison determination and the information restoration may be collectively performed by the integrated software.

  When the signal output device 10 and the signal input device 20 described above are provided, a plurality of signals each representing two states are superimposed without depending on any signal state of each signal, It is possible to obtain a signal input / output device that can transmit information included in a plurality of signals in a state where the number of signals is small and can be restored. Hereinafter, application examples in which such a signal input / output device is applied to a rotation detection device that detects the rotation of a rotating body and a wheel state monitoring device will be described.

[Application example]
FIG. 13 is a schematic block diagram illustrating an example in which the rotation sensor 50 detects the rotation of the rotating body 40. The wheel 40 is provided with a magnetic body that circulates so that different poles are adjacent to each other. The rotation sensor 50 is provided with a magnetic sensor 51 such as a Hall IC, and detects a magnetic pole provided on the wheel 40 and outputs a detection signal. The magnetic sensor 51 includes a pair of sensor elements 51a and 51b. The sensor elements 51a and 51b are arranged at a distance obtained by adding or subtracting a distance of 1/2 or 1/4 to a distance that is an integral multiple of the pitch of the magnetic body provided on the wheel 40. This is because the signal processing unit 52 detects the rotation direction, as will be described later. In applications where the rotation direction is not detected, the magnetic sensor 51 may be configured by a single sensor element. The detection result of the rotation sensor 50 is input together with the rotation sensor 50 or to an information processing unit (not shown) provided separately, and the rotation speed and the rotation direction are digitized. And it is used for various control by an information processing part and another control apparatus (not shown). The rotation sensor 50 and the information processing unit constitute a rotation detection device.

  In FIG. 14, the example of the waveform of the detection signal which detected the rotation of the rotary body 40 with the rotation sensor 50 is shown. The signal MSA is a rotation detection result by the sensor element 51a. The rotation speed is represented by the period of the rectangular wave signal. The signal MSB is a rotation detection result by the sensor element 51b. Similar to the signal MSA, the rotation speed is represented by the period of the rectangular wave signal. As described above, the sensor elements 51a and 51b are installed at a pitch slightly deviated from an integral multiple of the mounting pitch of the magnetic bodies provided in the rotating body 40. Therefore, the phases of the signal MSA and the signal MSB have a shift as shown in FIG. This deviation appears in a direction different by 180 degrees depending on the rotation direction of the rotating body 40 when any one of the signals (MSA, MSB) is used as a reference. For example, when the rotating body 40 rotates in the forward direction, the sensor element 51b outputs the signal MSB_F with the signal MSA as a reference. When the rotating body 40 rotates in the backward direction, the sensor element 51b outputs the signal MSB_B with the signal MSA as a reference. The signal MSB_F and the signal MSB_B are thus signals having a phase difference of 180 degrees. Here, when the logical product of the signal MSA and the signal MSB is taken in the signal processing unit 52, when the rotating body 40 rotates forward, the rotation direction signal D is output as the signal D_F. When the rotating body 40 performs the reverse operation, the rotation direction signal D is output as the signal D_B.

  Here, the signal MSA (or MSB) is referred to as a rotation speed signal, and the signal D is referred to as a rotation direction signal. In the signal processing unit 52, the rotation speed signal MSA and the rotation direction signal D are made to have different amplitudes, and are preferably subjected to signal processing so that one amplitude is 50% of the other amplitude. . For example, in the waveform example shown in FIG. 14, the rotation direction signal D is 50% of the amplitude of the rotation speed signal MSA. Then, as shown in FIG. 16, the rotation speed signal MSA and the rotation direction signal D are superimposed by the signal superimposing means 18. In addition, the signal output device 10 including the signal superimposing means 18 may be provided in the signal processing unit 50. The superimposition signal SS is input to an ECU (Electronic Control Unit) (not shown) provided on the vehicle body side. The ECU corresponds to the signal input device 20 of the present invention. That is, the rotation detection device can be configured by including the signal input device 10, the signal output device 20, and the signal input / output device according to the present invention as described with reference to FIGS. The rotation speed signal MSA and the rotation direction signal D correspond to the first to third pulse signals S1 to S3 described with reference to FIGS.

  Moreover, the detection result of the rotation sensor 50 and the detection result of a sensor different from the rotation sensor 50 may be superimposed. FIG. 5 is a cross-sectional view of the wheel 40 </ b> A as the rotating body 40. The wheel 40 supports the tire 41 on the tire wheel 42 and rotates around the axle 43. The rotation sensor 50 detects the rotation (rotation direction, rotation speed) of the wheel 40A. The rotation sensor 50 may be a system using a magnetic sensor as described above, or may be an optical sensor using an optical encoder. The air pressure sensor 60 is provided in a valve portion that injects air into the tire 41 and measures the air pressure of the tire 41 and the temperature in the tire. The measured air pressure is transmitted to a receiving unit (not shown) on the vehicle body side by wireless transmission, for example. The measurement result by the air pressure sensor is transmitted by encoding a multi-bit digital signal into Manchester code or the like. Then, as shown in FIG. 17, the rotation speed signal MSA and the air pressure information signal are superimposed by the signal superimposing means 18.

  The rotation sensor 50 may include a receiving unit that receives, mixes, and demodulates a radio signal from the air pressure sensor 60. In this case, the signal processing unit 50 may further include the signal input device 10 including the signal superimposing means 18. In this case, as shown in FIG. 18, the rotation speed signal MSA, the rotation direction signal D, and the air pressure information signal may be superimposed by the signal superimposing means 18. Further, a tire temperature information signal may be superimposed.

  Information acquired by the air pressure sensor 60 and the rotation sensor 50 is input to an ECU (not shown) provided on the vehicle body side by a superposition signal SS. In the ECU, the information that the signal before superimposition has is restored from the superimposition signal SS. The ECU and other control devices connected to the ECU perform various controls of the vehicle based on information such as air pressure information, rotation speed, and rotation direction. The air pressure sensor 60, the rotation sensor 50, and the ECU constitute the wheel state monitoring device of the present invention. That is, the wheel state monitoring device can be configured by including the signal input device 10, the signal output device 20, and the signal input / output device according to the present invention as described with reference to FIGS. The rotation speed signal MSA, the rotation direction signal D, the air pressure information signal, and the tire temperature information signal correspond to the first to third pulse signals S1 to S3 described with reference to FIGS.

  As described above, a plurality of signals each representing two states can be overlapped without depending on any signal state of each signal, and the information of the plurality of signals can be restored with a small number of signal lines. It is possible to provide a technique that can be transmitted in a simple state.

Waveform diagram showing an example of superimposing two rectangular wave signals having different amplitudes according to the implementation of the present invention Waveform diagram illustrating the basic principle of the present invention in which two rectangular wave signals having different amplitudes are superimposed Waveform diagram illustrating an example of superposing two rectangular wave signals having different amplitudes Waveform diagram for explaining the basic principle of the present invention in which three rectangular wave signals having different amplitudes from each other are superimposed Schematic block diagram showing the configuration principle of the signal output device according to the present invention Schematic block diagram showing a configuration example of a signal output device according to the present invention Schematic block diagram showing another configuration example of the signal output device according to the present invention Schematic circuit diagram showing an example of a current-voltage converter of the signal input device according to the present invention FIG. 6 is a waveform diagram showing an example of reproducing information of an original rectangular waveform from a signal obtained by superimposing two rectangular waveform signals having different amplitudes by implementing the present invention; Schematic block diagram showing a configuration example of a signal input device according to the present invention Schematic block diagram showing another configuration example of the decoding unit of FIG. The schematic block diagram which shows the other structural example of the signal input device which concerns on this invention The schematic block diagram which shows an example of the rotation sensor with which the rotation detection apparatus which concerns on this invention is provided. Waveform diagram showing an example of the output signal of the rotation sensor shown in FIG. Sectional drawing of the wheel as an example of the rotary body shown in FIG. The schematic block diagram which shows the structural example of the signal output part with which the rotation detection apparatus which concerns on this invention is provided. The schematic block diagram which shows the structural example of the signal output part with which the state monitoring apparatus of the wheel which concerns on this invention is provided. The block diagram which shows the other structural example of the signal output part with which the wheel state monitoring apparatus which concerns on this invention is provided.

Explanation of symbols

10 Signal output device
20 Signal Input Device 21 Comparison Unit 22 Decoding Unit S1 First Pulse Signal S2 Second Pulse Signal SS Superimposition Signal TH1 First Threshold TH2 Second Threshold TH3 Third Threshold

Claims (4)

  Each signal represents two states as logic signals and superimposes a plurality of rectangular wave signals having different amplitudes, and the total number of the plurality of signals is n, and the power of 2 n depends on the signal level of the superimposed signals. A signal output device for generating a staircase signal representing the state of the.   2. The signal output device according to claim 1, wherein a total number of the plurality of signals is 2, and an amplitude of one of the two signals is 40% to 60% of an amplitude of the other signal.   Each signal represents two states depending on the signal level, and each signal level represented by a stepped signal in which a plurality of rectangular wave signals having different amplitudes are superimposed is represented by 2 as the total number of the plurality of signals. A signal input device comprising: a comparison unit that makes a determination based on a threshold value obtained by subtracting 1 from the nth power; and a decoding unit that reproduces two states represented by the plurality of signals based on the determination result of the comparison unit.   A signal input / output device having the signal output device according to claim 1 and the signal input device according to claim 3, wherein the plurality of signals are rectangular at a frequency according to a rotation speed of a vehicle wheel. A wheel state monitoring device comprising: an output signal of a rotation sensor that outputs a wave-like rotation detection signal; and a rectangular wave-like signal representing information on the air pressure of the wheel.

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