JP5278255B2 - Data communication method and data communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data communication method that transmits a plurality of information using a common signal line, while suppressing an increase in scale of a computing circuit and a program. <P>SOLUTION: The data communication method for transmitting first physical information showing speed information using a period of a pulse P1 (periodic signal F1) includes: transmitting second physical information different from the first physical information based on the number of continuous pulses P2, regarding a plurality of kinds of pulses P1, P2 selectively generated based on the pulse P1 and having the period of the pulse P1, and ending transmission of the second physical information based on the switching to the pulse P1. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a data communication method and a data communication apparatus for transmitting a plurality of types of physical information through a common signal line.

  In-vehicle systems such as ABS (anti lock braking system) and vehicle stability control devices use a rotational speed sensor for measuring the rotational speed of the wheels in order to perform the control. The rotational speed sensor is disposed in the vicinity of the wheel, and the detection result (rotational speed information) is transmitted to the vehicle-mounted control device using a signal line. As wheel information, there is information such as tire air pressure in addition to rotational speed information, which is detected by an air pressure sensor or the like. In recent years, many sensors are mounted on vehicles, and the number is expected to increase further. Therefore, if signal lines are individually provided for each sensor, the number of signal lines becomes enormous. Therefore, for example, a technique for transmitting a plurality of types of physical information through a common signal line has been proposed, such as superimposing another detection result such as a detection result of a pneumatic sensor on a signal line of a rotation speed sensor.

  For example, Patent Document 1 proposes a method for transmitting data supplied by a rotation speed sensor and additional data via a common signal line. This is to superimpose serial bit data between adjacent pulses using a pulsed rotational speed sensor signal as a trigger. Patent Document 2 proposes a method of superimposing serial bit data in a high period (high level period) of a pulse-like signal having a duty ratio of approximately 50% that is output in accordance with the rotation of the wheel. . This represents serial bit data by a superposed pulse that is larger than the pulse height of the pulse output according to the rotation of the wheel and narrower than the pulse.

Japanese translation of PCT publication No. 2001-505691 (2nd page, FIG. 1 etc.) JP-A-2005-274310 (paragraphs [0055]-[0062], FIG. 10, etc.)

  By the way, these methods are excellent in that other information can be superimposed on the signal line of the rotational speed sensor. However, if the rotational speed is high, necessary information cannot be suitably superimposed. There is sex. This is because the time (cycle) between adjacent pulses and the high period of the pulses are shortened, and it may be difficult to generate superimposable serial bit data.

  On the other hand, by providing a start bit, an end bit, and a parity bit, necessary information (serial bit data) can be transmitted in a plurality of cycles. However, when such a method is adopted, a control function corresponding to the information transmission side and the reception side is required, which may increase the scale of the arithmetic circuit and the program.

  An object of the present invention is to provide a data communication method and a data communication apparatus capable of transmitting a plurality of types of physical information through a common signal line while suppressing an increase in the scale of arithmetic circuits and programs.

  In order to solve the above problem, the invention according to claim 1 is selectively generated based on the pulse in the data communication method for transmitting the first physical information representing the speed information according to the period of the pulse. A plurality of types of pulses having a period of the pulse transmits second physical information different from the first physical information based on the number of consecutive one type of the pulses, and the one type of the pulses The gist is to end the transmission of the second physical information on the basis of switching to another type of pulse different from the above.

  According to the same configuration, the first physical information (speed information) and the second physical information can be transmitted using the plurality of types of pulses having the pulse and the period of the pulse, respectively. These transmissions can be realized by a common signal line. In addition, since the second physical information can be basically transmitted only by counting the number of consecutive times of the one type of the pulse, an arithmetic circuit, a program, etc. An increase in scale can be suppressed.

One type of the plurality of types of pulses may be a pulse having the same waveform as the original pulse (that is, an unprocessed pulse).
According to a second aspect of the present invention, in the data communication method according to the first aspect, the plurality of types of pulses are obtained by superimposing other pulses on a high level or low level period of the original pulse. The gist is that it is generated.

  According to this configuration, on the transmission side, the plurality of types of pulses can be generated by an extremely simple method of simply superimposing (combining) other pulses in the high level or low level period of the original pulse. Can do. The plurality of types of pulses on the receiving side can be easily identified by, for example, determining a threshold value of the amplitude of the pulse that changes when another pulse is superimposed.

  According to a third aspect of the present invention, in the data communication method according to the first aspect, the plurality of types of pulses are generated by changing a high level or low level period of the original pulse. This is the gist.

  According to this configuration, the plurality of types of pulses can be generated on the transmission side by an extremely simple method by simply changing the high-level or low-level period (pulse width) of the original pulse. Note that the identification of the plurality of types of pulses on the receiving side can be easily performed, for example, by measuring the high level or low level period of the changed pulse.

  According to a fourth aspect of the present invention, in the data communication method according to any one of the first to third aspects, the second physical information has a predetermined time during which the pulses of the other types are generated. Or each time the number of generations of the other types of pulses reaches a predetermined number, and the second physical information is stored in the predetermined time period during which the other types of pulses are generated. Alternatively, the gist is that the pulses of the other types are acquired within the predetermined number of generations.

  According to the same configuration, the second physical information acquired within the predetermined time during which the other type of the pulse is generated or within the predetermined number of times when the other type of the pulse is generated is The second physical information can be intermittently updated by repeatedly transmitting each time period.

  According to a fifth aspect of the present invention, in the data communication method according to any one of the first to third aspects, the second physical information is any one type of physical information that can be selected from a plurality of types. Any one type of physical information that can be selected from the plurality of types based on the number of consecutive times of the other types of pulses different from the one type of pulses prior to transmission of the second physical information. The gist is to transmit the selection information of the type.

  According to the configuration, the selection information of the type of physical information is transmitted based on the number of consecutive times of the pulse of another type different from the pulse of the one type prior to transmission of the second physical information. Thus, one type of the physical information corresponding to the selection information can be transmitted as the second physical information. Therefore, a plurality of types of physical information as the second physical information can be selectively transmitted through a common signal line.

  According to a sixth aspect of the present invention, in the data communication method according to any one of the first to third aspects, the other types of pulses that are switched after the transmission of the second physical information is performed for each cycle. The gist is to transmit the increase / decrease information of the second physical information.

  According to the configuration, the increase / decrease information of the second physical information for each cycle is transmitted by the other type of the pulse that is switched after the transmission of the second physical information is completed. The transmitted second physical information can be corrected for increase / decrease based on the increase / decrease information. Thus, after the transmission of the second physical information is completed, it is not necessary to retransmit the second physical information itself, and only the increase / decrease information needs to be transmitted for each pulse period. In addition, it is possible to further suppress an increase in the scale of arithmetic circuits and programs on both the receiving side and the receiving side. Further, the increase / decrease information can be transmitted through one signal line common to the first physical information and the like. In particular, the resolution of each number of the one type of pulses representing the second physical information is set larger than the resolution of each period of the other types of pulses representing the increase / decrease information. The time until the second physical information reaches the nominal value can be further shortened. On the other hand, after the transmission of the second physical information is completed (after reaching the nominal value), the second physical information can be corrected more or less finely based on the increase / decrease information, for example.

The increase / decrease information may represent maintenance (uncorrected) of the second physical information transmitted or corrected by the previous period.
The invention according to claim 7 is based on the periodic signal generating unit that generates a pulse having a period corresponding to the first physical information representing the speed information based on the detection signal output from the speed sensor, and the pulse. Thus, one type of the pulse having the period of the pulse is continuously generated by the number of times corresponding to the second physical information different from the first physical information, and is different from the one type of the pulse. The gist of the invention is that it includes a signal processing unit that switches to another type of pulse and outputs the pulse to a signal line.

  According to the same configuration, any one of the plurality of types of pulses is selectively output to the signal line, so that the first physical information (speed information) is changed according to the period of the pulses. It is transmitted through the signal line. In addition, the one type of the pulses that are continuously generated at the number of times corresponding to the second physical information are output to the signal line, so that the second physical information is determined according to the number of the pulses. Is transmitted through the signal line. In this way, transmission of the first physical information and the second physical information can be realized by a common signal line. Further, the second physical information can be transmitted (transmitted) simply by counting the number of consecutive times of the one type of pulse and outputting it to the signal line, so that it becomes the transmitting side. An increase in the scale of the signal processing unit (circuit configuration, program, etc.) can be suppressed. Similarly, on the receiving side, the second physical information can be received simply by counting the number of consecutive pulses of the one type output to the signal line. An increase in the scale of a circuit or a program can be suppressed.

  One type of the plurality of types of pulses may be a pulse having the same waveform as the original pulse (that is, an unprocessed pulse).

  According to the present invention, it is possible to provide a data communication method and a data communication apparatus capable of transmitting a plurality of types of physical information through a common signal line while suppressing an increase in the scale of arithmetic circuits and programs.

The side view which shows arrangement | positioning relationship, such as a magnet rotor and a sensor. The front view which shows a magnet rotor and a sensor. The block diagram which shows typically the structural example of the state detection apparatus of a wheel. Explanatory drawing which shows an example of the method of converting a detection signal into a digital count value. Explanatory drawing which shows an example of the method of producing | generating a periodic signal. The time chart which shows an example of the output signal of 1st Embodiment. The flowchart which shows the production | generation aspect of the output signal of 1st Embodiment. The time chart which shows an example of the output signal of 2nd Embodiment. The waveform example which shows the output signal of 2nd Embodiment. The time chart which shows an example of the correction aspect of the additional information of 2nd Embodiment. The example of a waveform which shows the output signal of 3rd Embodiment. Explanatory drawing which shows the method of producing | generating the periodic signal of 3rd Embodiment. The time chart which shows an example of the output signal of 3rd Embodiment. The time chart which shows an example of the output signal of a deformation | transformation form.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to a wheel state detection device that detects a rotation state of a vehicle wheel and the like will be described. The state detection device transmits information such as the detected rotation state of the wheel to an ECU (electronic control units) that performs control of an ABS, a skid prevention device (ESC: electronic stability control), and the like.

  As shown in FIGS. 1 and 2, a ring-shaped magnet rotor 8 provided for detection of the rotation state is fixed to a vehicle wheel 9 so as to rotate integrally. The magnet rotor 8 may be directly fixed to the wheel 9 or may be fixed to a shaft 7 (rotating shaft) that fixes the wheel 9 as shown in FIG. A sensor 10 that is a detection element for detecting the rotation of the wheel 9 (magnet rotor 8) is attached to a vehicle side that does not rotate with the wheel 9, such as a hub bearing. The sensor 10 is a magnetic detection sensor such as a Hall IC or a Hall IC provided with a Hall element, and is disposed to face the magnet rotor 8 with a predetermined interval A.

  The sensor 10 outputs a sinusoidal AC detection signal S according to the rotation of the wheel 9 and the magnet rotor 8. As shown in FIG. 2, the magnet rotor 8 is alternately provided with N poles and S poles at predetermined intervals, and when the NS poles pass through the sensor 10, an AC detection signal S is output. The AC frequency of the detection signal S changes depending on the speed at which the magnet rotor 8 passes through the sensor 10. This frequency is used to detect the rotational speed of the wheel 9 that rotates integrally with the magnet rotor 8. Since the above-described principle of magnetic detection is known, a detailed description thereof will be omitted.

  By the way, as the vehicle travels, a force in a direction along the shaft 7 in FIG. Due to this rotational shake, a change occurs in a predetermined distance A between the sensor 10 and the magnet rotor 8 that are arranged to face each other. As a result, the intensity of the magnetic field of the sensor 10 or the magnitude of the magnetic flux changes, so that the amplitude (wave height) of the AC component detection signal S output from the sensor 10 changes. In addition to the change in the wave height, the detection signal S also includes an increase / decrease in the DC component due to a temperature change. Therefore, the wheel state detection device performs the following signal processing to accurately detect the AC frequency. Do.

  That is, as shown in FIG. 3, the wheel state detection apparatus includes a receiving unit 1, a wave height detecting unit 2, a periodic signal generating unit 3 as a periodic signal generating unit, an output unit 4 constituting a signal processing unit, and And an additional signal generation unit 5. The receiving unit 1 is a functional unit that receives a detection signal S that is output in accordance with the rotation of the wheel 9 (magnet rotor 8). The detection signal S output from a sensor such as a rotation sensor (sensor 10) is often a high impedance signal. The receiving unit 1 includes a buffer 11 having a high input impedance and a low output impedance. The wave height detection unit 2 is a functional unit that detects the wave height of the detection signal S. The periodic signal generation unit 3 is a functional unit that generates a periodic signal F1 having a period corresponding to the period of the detection signal S based on a threshold value (Th) set according to the wave height (peak) of the detection signal S. . The additional signal generation unit 5 is a functional unit that generates the additional signal F3. The output unit 4 is a functional unit that synthesizes the periodic signal F1 and the additional signal F3 and outputs them as one output signal F. In the present embodiment, the wheel state detection device is configured by an electronic circuit having a microcomputer or the like as the core, and each functional unit described above is realized by hardware and cooperation of hardware and software. ing.

  First, the functions of the wave height detector 2 and the periodic signal generator 3 will be described in detail. In the following, a case where the detection signal S is A / D (analog / digital) converted and digital signal processing is described as an example. FIG. 4 shows an example of a method for converting the detection signal S into the digital count value D, and FIG. 5 shows an example of a method for generating the periodic signal F1. As described above, the detection signal S is impedance-converted in the receiving unit 1, and at this time, it is also possible to perform signal amplification processing or the like at the same time. Therefore, strictly speaking, in the wave height detection unit 2, not the detection signal S received by the reception unit 1 but the signal output from the reception unit 1 is A / D converted. Can be considered to be the same signal before and after the receiving unit 1. Therefore, hereinafter, the signal output from the receiving unit 1 is also referred to as a detection signal S.

  As shown in FIG. 3, the wave height detection unit 2 includes an A / D conversion unit 21, an inversion threshold setting unit 22, a comparator 23, a counter 24, and a register 25. The A / D conversion unit 21 is a functional unit that A / D converts the detection signal S in accordance with a predetermined condition, and includes an A / D converter. There are various types of A / D converters such as a flash type, a successive approximation type, and an integration type, and an optimal one is appropriately selected according to the conversion speed, conversion accuracy, and the like. Also, the output form of the A / D converter also outputs an absolute value as a digital value with respect to an analog input, or outputs a trigger signal every time the analog input changes by a predetermined amount, etc. There are various forms, which are appropriately selected. In the present embodiment, an absolute value is not output as a digital value, but an example in which an A / D converter that outputs a trigger signal for every predetermined amount of change (predetermined step) is used as an example. explain.

  In this embodiment, this type of A / D converter is used for the following countermeasures. In other words, even when the amplitude center of the detection signal S of the sensor 10 fluctuates, that is, when the offset of the DC component fluctuates, appropriate signal processing is possible according to the amplitude (wave height) of the detection signal S. This is because. However, the offset for the DC component can be eliminated by another signal processing circuit using a coupling capacitor, a DC bias, or the like. Therefore, an A / D converter that outputs an absolute value as a digital value may be used.

  The A / D converter 21 outputs a trigger signal each time the detection signal S changes by a predetermined amount, specifically, every time the detection signal S changes by a predetermined amount toward the peak P side of the oscillating waveform. As the wave height of the oscillating waveform is referred to as “peak to peak”, “the peak P of the waveform” refers to both the peak side and the valley side of the waveform. As shown in FIG. 4, a trigger signal is output on the peak P side from the predetermined inversion threshold R, and this trigger signal is counted by the counter 24 to become a digital count value D. In FIG. 4, the digital count value D is a stepwise change along the sinusoidal detection signal S, with the values 5, 6, 7.

  When the detection signal S reaches the peak P, the detection signal S does not change toward the peak P by a predetermined amount. Therefore, the digital count value D is in a state in which a constant value continues in the vicinity of the peak P of the detection signal S. In the example shown in FIG. 4, the digital count value D continues at “25”, which is the peak value Dp of the digital count value D. Note that when the counter 24 is an up / down counter and the detection signal S changes by a predetermined amount in one direction (the direction of one peak P) and in the opposite direction, different trigger signals are displayed in the A / D converter. In the configuration output from the digital signal 21, the digital count value D corresponding to the waveform of the detection signal S can be obtained. However, in this case, there is a possibility that the detection signal S may follow even when the detection signal S increases or decreases at a position other than the peak P due to noise or the like. Therefore, in the present embodiment, the counter 24 is configured as an up counter. When the detection signal S changes in the reverse direction (the direction opposite to the one peak P, that is, the direction of the other peak P), a predetermined change width h corresponding to a plurality of counts of the digital count value D is set. When it exceeds, it is comprised so that it may determine with having exceeded one peak P and reversed. That is, hysteresis is set.

  Specifically, the inversion threshold value setting unit 22 sets an inversion threshold value R for determining whether or not the detection signal S is inverted beyond the corresponding peak P. Here, the inversion threshold R is set with a change width h corresponding to 5 counts of the digital count value D. The A / D converter 21 outputs the analog value of the detection signal S at the time of outputting the latest trigger signal (or the analog value that is the A / D conversion threshold) to the inversion threshold setting unit 22. The inversion threshold setting unit 22 sets the inversion threshold R by reflecting a predetermined change width h (hysteresis value) in the received analog value. When the detection signal S is rising (when the peak P is on the peak side), the change width h (hysteresis value) is subtracted from the analog value, and the inversion threshold R is set. When the detection signal S is decreasing (when the peak P is on the valley side), the change width h is added to the analog value, and the inversion threshold R is set.

  The inversion threshold R is input to the comparator 23 that functions as an inversion determination unit. The comparator 23 compares the detection signal S with the inversion threshold R to determine whether the detection signal S has been inverted beyond the corresponding peak P. The counter 24 that has received the determination output from the comparator 23 transfers the peak value Dp of the digital count value D to the register 25 and stores it, and also presets its own digital count value D. In the example shown in FIG. 4, the counter 24 stores “25” as the peak value Dp of the digital count value D in the register 25 and presets its own digital count value D to “5”. The preset value “5” is the number of steps of the digital count value D corresponding to the change width h.

  After that, the A / D converter 21 that has received the determination output from the comparator 23 outputs a trigger signal when the detection signal S changes by a predetermined amount in a direction opposite to that before receiving the determination output. In response to this trigger signal, the counter 24 increments the digital count value D. Further, the inversion threshold setting unit 22 that has received the determination output from the comparator 23 switches the calculation method when setting the inversion threshold R. That is, the inversion threshold value setting unit 22 switches whether the change width h is subtracted or added to the analog value received from the A / D conversion unit 21.

  The periodic signal generator 3 acquires the latest peak value Dp of the digital count value D from the register 25 and sets the threshold Th. The threshold Th is a threshold for determining a periodic signal, and is calculated and set by multiplying the peak value Dp by a predetermined coefficient k. The threshold value Th may be calculated and set in the register 25, and the periodic signal generation unit 3 may acquire the threshold value Th from the register 25. In any case, the periodic signal generator 3 determines the output timing of the periodic signal F1 based on the threshold Th and the digital count value D acquired from the counter 24. In the present embodiment, the periodic signal F1 is inverted at each output timing. That is, if the wheel 9 (magnet rotor 8) is rotating at a constant speed, a pulse (rectangular wave) having a duty ratio of 50% is generated as the periodic signal F1. However, the periodic signal generation unit 3 does not necessarily have to generate the waveform of the periodic signal F1, and only needs to determine the output timing such as the change point of the pulse waveform. The waveform generation may be performed in the output unit 4.

  Hereinafter, description will be made using specific numerical values. Here, in order to facilitate understanding, a case where a waveform is generated by the periodic signal generation unit 3 will be described as an example. The peak value Dp of the valley on the left side of the detection signal S in FIG. 5 is “23”. For example, when the coefficient k is “0.8”, the threshold Th is “18”. Here, the fraction is rounded down for easy explanation. In this case, when the digital count value D received from the counter 24 reaches “18”, the periodic signal generator 3 generates the periodic signal F1. At this time, the wave height of the periodic signal F1 changes from the reference value C which is a low level to the signal level PL which is a high level in the positive direction. Further, the peak value Dp of the peak of the detection signal S in FIG. 5 is “25”, and the threshold value Th is “20”. In this case, when the digital count value D received from the counter 24 reaches “20”, the periodic signal generator 3 generates the periodic signal F1 in the same manner as described above. At this time, the wave height of the periodic signal F1 changes from the signal level PL to the reference value C in the negative direction. That is, the periodic signal F1 is inverted every time the digital count value D reaches the threshold Th, and is generated one by one in one period of the detection signal S. As described above, the periodic signal generation unit 3 has a period corresponding to the period of the detection signal S (proportional to the period) based on the threshold Th set according to the wave height (peak value Dp) of the detection signal S. A signal F1 is generated. The periodic signal F1 provides rotational speed information of the wheel 9 (magnet rotor 8) as first physical information representing speed information according to the period.

  The additional signal generation unit 5 receives additional information (such as air pressure information and temperature information) X as second physical information from, for example, an air pressure sensor or a temperature sensor. The additional signal generation unit 5 calculates and sets the number of times n (= X / resolution) by dividing the additional information X by the resolution set for each cycle of the periodic signal F1. Here, the fraction is rounded down for easy explanation. Then, the additional signal generating unit 5 synchronizes with the timing at which the wave height of the periodic signal F1 changes to the signal level PL, and the pulse has a sufficiently narrow width compared to the period (pulse width) of the high level of the periodic signal F1. A pulse-like additional signal F3 having a width is generated. The additional signal generation unit 5 continuously generates the additional signal F3 for each rising timing of the periodic signal F1 for the number n set in the above-described manner. Further, after the additional signal generating unit 5 continuously generates the additional signal F3 for the number n times, the additional signal generating unit 5 stops generating a new additional signal F3 until a predetermined time Td has elapsed. During this time, the additional signal generator 5 receives new additional information X. The predetermined time Td is set to a time sufficient for receiving new additional information X (for example, a time corresponding to a plurality of times of the normal period T (see FIG. 5) of the periodic signal F1). Then, after the predetermined time Td has elapsed (after receiving the new additional information X), the additional signal generation unit 5 continues the additional signal F3 for the number of times corresponding to the additional information X in this manner. Generate automatically. That is, the additional signal generation unit 5 alternately receives new additional information X and continuously generates additional signals F3 for the number of times corresponding to the additional information X. Note that the additional signal F3 is generated in the additional signal generation unit 5, but it is not always necessary for the additional signal generation unit 5 to generate the additional signal F3, similarly to the periodic signal F1. The additional signal generator 5 only needs to determine an output timing such as a change point of the pulse waveform, and the output unit 4 may perform the waveform generation.

  The output unit 4 generates an output signal F by combining the periodic signal F1 generated by the periodic signal generation unit 3 and the additional signal F3 generated by the additional signal generation unit 5. Therefore, as shown in the time chart of FIG. 6, in the data communication method (communication protocol) of the present embodiment, the periodic signal F1 is generated as it is as the output signal F within the predetermined time Td when the generation of the additional signal F3 is stopped. Is done. Hereinafter, this type of output signal F is also referred to as a first type of pulse P1 for convenience. Further, after the elapse of the predetermined time Td, a signal in which the additional signal F3 is superimposed in synchronization with the rising edge of the periodic signal F1, continuously for the number of times corresponding to the new additional information X within the predetermined time Td, that is, A signal having a raised wave height is generated as an output signal F. Hereinafter, this type of output signal F is also referred to as a second type pulse P2 for convenience. Here, an example of a waveform in which the additional signal F3 is superimposed as a higher level signal when the periodic signal F1 is at a high level is shown, but the waveform example is not limited to this. When the periodic signal F1 is at a low level, the additional signal F3 may be superimposed as a signal having a lower level.

  Then, the output unit 4 outputs the output signal F (pulse P1 or P2) thus generated to the signal line L. As described above, the periodic signal F1 constituting the output signal F provides the rotational speed information of the wheel 9 (magnet rotor 8) according to the period. Further, the additional signal F3 constituting the output signal F provides the additional information X by the number of consecutive times. Therefore, the transmission side (wheel state detection device) transmits (transmits) the rotational speed information and the additional information X to the ECU through a common signal line L. On the other hand, the receiving side (ECU) receives (outputs) the rotational speed information and the additional information X by inputting the output signal F output to the signal line L. Specifically, the ECU compares the output signal F with a predetermined threshold Th1 smaller than the wave height of the periodic signal F1, thereby comparing the rising timing of the output signal F, that is, the output signal F (pulse P1 or P2). Get the period. And ECU acquires the rotational speed information of the wheel 9 (magnet rotor 8) by the period of this output signal F. Alternatively, the ECU compares the output signal F with a predetermined threshold Th2 that is larger than the wave height of the periodic signal F1 and smaller than the wave height of the periodic signal F1 (that is, the pulse P2) raised by the additional signal F3. Then, the number n of times the additional signal F3 is continuously generated is counted and acquired. Then, the ECU obtains the additional information X by multiplying the number n of the additional signal F3 by the above-described resolution set per time.

Next, the generation control mode of the output signal F on the transmission side (wheel state detection device) will be described with reference to the flowchart shown in FIG.
As described above, the periodic signal F1 is inverted at every output timing determined based on the threshold value Th and the digital count value D. First, when the periodic signal F1 is inverted to a low level (reference value C) (S (step) 11), the number of pulses P2 corresponding to the additional information X is increased (the periodic signal F1 raised by the additional signal F3). It is determined whether the elapsed time Tp after the output of) is equal to or longer than the predetermined time Td (S12). Here, if it is determined that the elapsed time Tp is not equal to or longer than the predetermined time Td, the communication flag J is set to “0” because it is within the time for receiving the new additional information X (S13). When it is determined that the elapsed time Tp is equal to or greater than the predetermined time Td, the communication flag J is set to “1” because it is necessary to transmit the new additional information X received within the immediately preceding predetermined time Td ( S14).

  When the periodic signal F1 is inverted to a high level (signal level PL) (S15), it is determined whether or not the communication flag J is “1” (S16). If it is determined that the communication flag J is not “1”, the new additional information X received within the predetermined time Td is set as the sensor value (S17), and the additional information X is further displayed with the above-described resolution. The number of times n is calculated and set (S18). On the other hand, when the communication flag J is determined to be “1” in S16, the additional signal F3 is output in synchronization with the rising timing of the periodic signal F1 (S19). Then, a value obtained by subtracting “1” from the number n is set as a new number n (S20), and it is further determined whether or not the number n is “0” (S21). If it is determined that the number of times n is “0”, since the output of the additional signal F3 (pulse P2) for the number of times n set in S18 is completed, the elapsed time Tp is set to “0” (reset). (S22). Further, when it is determined in S21 that the number of times n is not “0”, or when the process of S18 or S22 is completed, the process returns to S11 and the same process is repeated. As described above, the number n corresponding to the new additional information X is calculated and set within the predetermined time Td, and the pulse P2 (periodic signal raised by the additional signal F3 is continuously generated for the number n after the predetermined time Td has elapsed. F1) is output to the signal line L. Thus, as described above, the rotational speed information and the additional information X are transmitted (transmitted) from the transmitting side (wheel state detection device) to the receiving side (ECU) through a common signal line L. is there.

As described above in detail, according to the present embodiment, the following effects can be obtained.
(1) In this embodiment, the first physical information (rotational speed information) and the second physical information (additional information X) are a plurality of types of pulses having the period of the periodic signal F1 (pulse P1) and the periodic signal F1. Since transmission can be performed using P1 and P2, respectively, these transmissions can be realized by a single signal line L. Further, since the second physical information can be basically transmitted only by counting the number of consecutive pulses P2, the increase in the scale of arithmetic circuits and programs on both the transmission side and the reception side is suppressed. be able to.

  In particular, although the detection signal S (periodic signal F1) of the sensor 10 is used, the period of the detection signal S does not change, so the processing circuit itself relating to detection of rotational speed information on the receiving side (ECU) is changed. You don't have to.

  (2) In the present embodiment, on the transmission side, an extremely simple method of simply superimposing (synthesizing) another pulse (additional signal F3) in the high level period of the original pulse P1 (periodic signal F1), A plurality of types of pulses P1, P2 can be generated. It should be noted that the plurality of types of pulses P1 and P2 on the receiving side can be easily identified by, for example, determining a threshold value of the amplitude of the pulse P2 that changes when another pulse (additional signal F3) is superimposed.

  (3) In the present embodiment, the second physical information (additional information X) acquired within the predetermined time Td at which the pulse P1 is generated is repeatedly transmitted at each elapse of the period. Physical information can be updated intermittently. In particular, since the acquisition and transmission of the additional information X can be automatically repeated by managing the predetermined time Td (time keeping), this is realized by adding a small circuit or the like on both the transmission side and the reception side. Can do.

(Second Embodiment)
A second embodiment in which the present invention is applied to a wheel state detection device will be described below. In the second embodiment, transmission of additional information X (hereinafter also referred to as “additional information Xs” for convenience) itself, which is basically an initial value, is performed only once after power-on, and thereafter a periodic signal is transmitted. Since only the increase / decrease information of the additional information X for each cycle of F1 is transmitted and the additional information X is updated, the configuration is different from that of the first embodiment. Description is omitted.

  FIG. 8 is a time chart showing the output signal F in the present embodiment. As shown in the figure, in the data communication method (communication protocol) of this embodiment, when the vehicle power supply (ignition switch) is turned on, the output of the periodic signal F1 as the output signal F is accompanied with the start of rotation of the wheels 9. Output begins. Usually, after turning on the vehicle, there is a certain time difference until the rotation of the wheel 9, that is, the output of the periodic signal F1 is started. In the present embodiment, the additional signal generation unit 5 receives the additional information Xs as an initial value using this time difference, and the number n (= Xs) divided by the resolution set per period of the periodic signal F1. / Resolution) is calculated and set. Then, the additional signal generation unit 5 continuously stops generating the additional signal F3 for the number n according to the additional information Xs, and then starts and continues to generate the additional signal F3. A control period after power-on in which generation of the additional signal F3 is stopped is referred to as “learning mode”, and a subsequent control period is referred to as “normal mode”.

  Accordingly, in the learning mode, the output unit 4 generates and outputs the periodic signal F1 as it is as the output signal F continuously for the number n of times corresponding to the additional information Xs. Thereby, the transmission side (wheel state detection device) transmits (transmits) the rotational speed information and the additional information Xs to the ECU through the common single signal line L in accordance with the first embodiment. Become. On the other hand, when the receiving side (ECU) inputs the output signal F output to the signal line L, the rotational speed information and the additional information Xs are transmitted (received).

  On the other hand, in the normal mode, transmission of the increase / decrease information of the additional information Xs serving as an initial value is started. That is, the additional signal generation unit 5 generates the additional signal F3 according to the difference value (increase / decrease information for each period) between the additional information X in the previous period of the periodic signal F1 and the additional information X in the current period. Generate every. Accordingly, the output unit 4 generates an output signal F obtained by synthesizing the additional signal F3 with the periodic signal F1 for each period of the periodic signal F1. In the present embodiment, three values “−1”, “± 0”, and “+1” are assigned as the difference value, and the difference value is multiplied by the resolution set per unit. The amount of increase / decrease in the additional information X in the normal mode is obtained. In other words, in the normal mode, by adding the increase / decrease amount for each period of the periodic signal F1 to the additional information Xs that is the initial value, the latest additional information X can be updated each time.

  In the present embodiment, the resolution (for example, “1”) set to the difference value per unit in the normal mode is compared with the resolution (for example, “5”) set for each period signal F1 in the learning mode. Is set sufficiently small. This is because, in the learning mode, the additional information X is started up to the initial value (Xs) more quickly, and in the normal mode, the additional information X is updated more finely (increase / decrease correction).

  FIG. 9 is a waveform diagram showing an output signal F obtained by synthesizing the additional signal F3 corresponding to each difference value (−1, ± 0, +1) with the periodic signal F1. As shown in the figure, the following three types of additional signal F3 are generated according to the difference value of the additional information X, and the output signal F is also shaped into three types of waveforms (pulses) Fa to Fc accordingly. . Here, an example of a waveform in which the additional signal F3 is superimposed as a higher level signal when the periodic signal F1 is at a high level is shown, but the waveform example is not limited to this. When the periodic signal F1 is at a low level, the additional signal F3 may be superimposed as a signal having a lower level.

  The output signal Fa is a case where an additional signal F3 consisting of one pulse is superimposed. This period indicates that the additional information X is reduced by one unit with respect to the previous period (difference value: “−1”). The output signal Fb is a case where an additional signal F3 consisting of two pulses is superimposed. For example, when the pulse width of one pulse of the additional signal F3 is 50 μs, two pulses are superimposed with an interval of 50 μs. This period indicates that the additional information X does not increase or decrease with respect to the previous period (difference value: “± 0”). The output signal Fc is a case where an additional signal F3 consisting of three pulses is superimposed. Similar to the output signal Fb, three pulses are superimposed with an interval of 50 μs. This period indicates that the additional information X is increased by one unit with respect to the previous period (difference value: “+1”).

  For example, in the time chart of FIG. 10, at the times t1, t2, and t5, the number of pulses of the additional signal F3 is “3”, and the additional information X is increased by one unit. At time t3, the number of pulses of the additional signal F3 is “1”, and the additional information X is reduced by one unit. At times t4 and t6, the number of pulses of the additional signal F3 is “2”, and the additional information X is maintained.

  Therefore, the cumulative difference value SD after transmission of the additional information Xs is calculated according to the following equation (1) using the number of pulses (period number) of the periodic signal F1 and the number of pulses of the additional signal F3 in the normal mode. The value can be obtained.

ここで、ａｊは所定閾値Ｔｈ１と交差したパルス数、即ち周期信号Ｆ１のパルス数であり、ｂｊは所定閾値Ｔｈ２と交差したパルス数、即ち付加情報Ｘの差分値を示す付加信号Ｆ３のパルス数である。出力信号Ｆを受け取ったＥＣＵは、各周期において累積の差分値ＳＤを増減させてこれを更新してもよいし、所定の期間の経過後にまとめて演算して累積の差分値ＳＤを求めてもよい。なお、初期値として伝送された付加情報Ｘｓは、その後の累積の差分値ＳＤに１単位当たりの分解能を乗じたものが加算されることで、最新の付加情報Ｘとして更新される。

Here, aj is the number of pulses crossing the predetermined threshold Th1, that is, the number of pulses of the periodic signal F1, and bj is the number of pulses crossing the predetermined threshold Th2, that is, the number of pulses of the additional signal F3 indicating the difference value of the additional information X. It is. The ECU that has received the output signal F may update the cumulative difference value SD by increasing or decreasing it in each cycle, or may calculate the cumulative difference value SD by collectively calculating after a predetermined period. Good. Note that the additional information Xs transmitted as the initial value is updated as the latest additional information X by adding the subsequent accumulated difference value SD multiplied by the resolution per unit.

Here, according to Expression (1), the accumulated difference value SD is as follows at each time t0 to t6 in FIG.
Time t0: 0
Time t1: 1 = 3−2 × 1
Time t2: 2 = 6−2 × 2
Time t3: 1 = 7−2 × 3
Time t4: 1 = 9−2 × 4
Time t5: 2 = 12-2−5
Time t6: 2 = 14−2 × 6
In addition, Formula (1) can also be interpreted like the following Formula (2).

ここで、式（２）の右辺の第１項は、矩形波（出力信号Ｆ）の前周期までの累積の差分値ＳＤを示している。例えば、図１０における時刻ｔ１〜ｔ６を式（２）のｎの可変域と考える。式（２）の右辺の第１項は、時刻ｔ５において確定されている累積の差分値ＳＤ（＝１２）である。一方、式（２）の右辺の第２項は、時刻ｔ５から時刻ｔ６へ時間が経過したときの差分（＝２）を示している。つまり、この通信プロトコルによれば、出力信号Ｆを受け取ったＥＣＵが、各周期において累積の差分値ＳＤを増減させて更新することも可能であり、所定の期間の経過後にまとめて演算して累積の差分値ＳＤを求めることも可能であることが一層よく理解できる。

Here, the first term on the right side of Equation (2) represents the accumulated difference value SD up to the previous period of the rectangular wave (output signal F). For example, the times t1 to t6 in FIG. 10 are considered as the variable range of n in the equation (2). The first term on the right side of Equation (2) is the cumulative difference value SD (= 12) that has been determined at time t5. On the other hand, the second term on the right side of Equation (2) represents the difference (= 2) when time elapses from time t5 to time t6. That is, according to this communication protocol, the ECU that has received the output signal F can also update the cumulative difference value SD by increasing / decreasing it in each cycle. It can be better understood that the difference value SD can be obtained.

  In this way, in each cycle of the rectangular wave (output signal F), the cumulative difference value SD can be updated by a simple calculation of adding a difference (including a negative value) to the cumulative difference value SD up to the previous cycle. Therefore, the calculation load of the ECU that receives the output signal F is reduced, and the calculation time is also shortened. It is also possible to suppress the capacity of temporary storage means such as a RAM for temporarily storing data.

  Even if the accumulated difference value SD is obtained in any manner, the latest additional information Xs can be obtained by adding the difference value SD multiplied by the resolution per unit to the additional information Xs as an initial value. Can be requested.

As described above in detail, according to the present embodiment, in addition to the effects (1) and (2) in the first embodiment, the following effects can be obtained.
(1) In the present embodiment, the increase / decrease in the second physical information for each cycle is performed by pulses (output signals Fa to Fc) that are switched after the end of transmission of the second physical information (additional information Xs) (after the learning mode). By transmitting information (difference value), the second physical information can be corrected to increase or decrease based on the increase / decrease information. As described above, after the learning mode, it is not necessary to retransmit the second physical information itself, and only the increase / decrease information needs to be transmitted for each pulse period. Etc. can be further suppressed. Further, the increase / decrease information can be transmitted through a single signal line L that is common with the first physical information and the like. In particular, the resolution of each number of pulses P1 representing the second physical information is set to be larger than the resolution of each period of the other types of pulses (output signals Fa to Fc) representing the increase / decrease information. The time required for the physical information to reach the nominal value can be further shortened. On the other hand, after the learning mode (after reaching the nominal value), the second physical information can be corrected more or less finely based on the increase / decrease information, for example.

  (2) In the present embodiment, the transition from the learning mode to the normal mode can be automatically recognized by switching from the pulse P1 (periodic signal F1) to the pulse (output signals Fa to Fc). Can be omitted.

  (3) In this embodiment, since the roles of the communication states of the pulse P1 (periodic signal F1) and the pulses (output signals Fa to Fc) are different from each other, the combined use does not hinder communication.

(Third embodiment)
A third embodiment in which the present invention is applied to a wheel state detection device will be described below. The third embodiment is different from the second embodiment in that the generation mode of the output signal F (periodic signal, additional signal) according to the difference value of the additional information X is changed. Detailed description of similar parts is omitted.

  As shown in FIG. 11, the periodic signal F1 of the present embodiment has a wave height that reaches the signal level PL at the output timing determined based on the threshold value Th and the digital count value D, as in the first embodiment. The pulse width is a sufficiently narrow pulse width W as compared with the period T of the detection signal S. The additional signal F3a generated according to the difference value of the additional information X has the following three types, and the output signal F is also shaped into three types of waveforms (pulses) Fa to Fc accordingly. That is, the additional signal F3a is superimposed as a signal having the same level (signal level PL) as the wave height without leaving a gap with the periodic signal F1 at the timing when the wave height of the periodic signal F1 switches to the reference value C. . As a result, the output signal F has an apparently widened pulse width W1 of the pulse width W of the periodic signal F1. This pulse width W1 is also a pulse width W that is sufficiently narrower than the period T of the detection signal S. Here, in accordance with the timing at which the wave height of the periodic signal F1 switches to the reference value C, the additional signal is superimposed as a signal having the same level (signal level PL) as the wave height without leaving an interval from the periodic signal F1. Although the example of the waveform of F3a is shown, it is not limited to this. For example, when the interval (pulse width) when the wave height of the periodic signal F1 is at the reference value C is sufficiently narrower than the cycle T of the detection signal S, the timing at which the wave height of the periodic signal F1 switches to the signal level PL. The low-level period of the additional signal F3a (that is, the pulse P1 (periodic signal F1) to be superposed as a signal having the same level (reference value C) as the wave height without changing the interval with the periodic signal F1 is changed. It may be an additional signal F3a).

  The output signal Fa is a case where an additional signal F3a consisting of one pulse is superimposed. In the present embodiment, the pulse width of one pulse of the additional signal F3 is equal to the pulse width W of the periodic signal F1. Therefore, when the pulse width W of the periodic signal F1 is 50 μs, the pulse width W of the additional signal F3 is also 50 μs, and the apparent pulse width W1 of the periodic signal F1 (output signal Fa) is 2 W (= 100 μs). This period indicates that the additional information X is reduced by one unit with respect to the previous period (difference value: “−1”). The output signal Fb is a case where an additional signal F3a consisting of two pulses is superimposed. In this case, since two additional signals F3 of 50 μs are superimposed on the periodic signal F1 without any interval, the apparent pulse width W1 of the periodic signal F1 (output signal Fb) is 3 W (= 150 μs). This period indicates that the additional information X does not increase or decrease with respect to the previous period (difference value: “± 0”). The output signal Fc is a case where an additional signal F3 consisting of three pulses is superimposed. In this case, the apparent pulse width W1 of the periodic signal F1 (output signal Fc) is 4 W (= 200 μs). This period indicates that the additional information X is increased by one unit with respect to the previous period (difference value: “+1”).

  Here, a generation mode of the periodic signal F1 in the present embodiment will be described. FIG. 12 shows an example of a method for generating the periodic signal F1. Similar to the first embodiment, the periodic signal F1 has its wave height at the output timing determined based on the threshold Th and the digital count value D (here, the timing when the digital count value D reaches “18”). Changes to the signal level PL. The periodic signal F1 has a pulse width W that is sufficiently narrower than the period T of the detection signal S. Thereafter, the generation of the periodic signal F1 is repeated at the output timing determined in the above-described manner. In the present embodiment, the periodic signal F1 is generated when the detection signal S changes from the valley side to the mountain side, but instead of or in addition to this, the detection signal S is Similarly, the periodic signal F1 may be generated when changing from the mountain side to the valley side. In particular, when the periodic signal F1 is generated even when the detection signal S changes from the peak side to the valley side, the period of the periodic signal F1 is the half period (= T / 2) of the detection signal S. In any case, the periodic signal generation unit 3 has a period corresponding to the period of the detection signal S (proportional to the period) based on the threshold Th set according to the wave height (peak value Dp) of the detection signal S. A signal F1 is generated. It goes without saying that the periodic signal F1 (output signal F) has a period corresponding to the period of the detection signal S regardless of the superposition of the additional signal F3.

  As in the first embodiment, aj related to the calculation of the accumulated difference value SD in the normal mode is the number of pulses crossing the predetermined threshold Th1, that is, the number of pulses of the periodic signal F1. On the other hand, bj is obtained from the apparent pulse width W1 of the periodic signal F1. Specifically, the number of pulses of the additional signal F3a is obtained by setting “bj = (W1 / W) −1”.

  Then, as shown in FIG. 13, after the additional information Xs, which is the initial value in the learning mode, is transmitted, the increase / decrease amount for each period of the periodic signal F1 is integrated in the normal mode as in the first embodiment. By doing so, the latest additional information X can be updated each time.

As described above in detail, according to the present embodiment, the following effects can be obtained in addition to the same effects as those of the second embodiment.
(1) In this embodiment, a plurality of types of pulses (output signals Fa to Fc) are generated by changing the high-level period (pulse width W1) of the original pulse P1 (periodic signal F1). Yes. Therefore, on the transmission side, a plurality of types of pulses can be generated by an extremely simple method by simply changing the high-level period of the original pulse P1. Note that the identification of a plurality of types of pulses (output signals Fa to Fc) on the receiving side can be easily performed by, for example, measuring a high-level period of the changed pulse.

  Particularly, since the amplitude (wave height) of the pulse does not change as in the case where another pulse is superimposed on the high level period of the original pulse P1, the amplitude of the pulse is used to identify a plurality of types of pulses. Therefore, the circuit configuration on the receiving side (ECU) can be further simplified. Specifically, in the case of pulses P1 and P2 (see FIG. 6) that change the amplitude (wave height), there are three types of current output, two pulse number determination thresholds (predetermined thresholds Th1 and Th2), and two timer inputs of the microcomputer. In the case of pulses that change the pulse width (F1, Fa to Fc: see FIG. 11), two types of current output, one pulse number determination threshold (predetermined threshold Th1), and one microcomputer timer input are required. Therefore, it is presumed that the circuit configuration on the receiving side is advantageous.

In addition, you may change the said embodiment as follows.
The second physical information may be any one type of physical information that can be selected from a plurality of types of physical information (for example, air pressure information and temperature information). In this case, prior to transmission of one type of physical information, it is necessary to transmit selection information of the type of physical information together. This selection information may be transmitted based on the number of consecutive pulses of another type different from the one type of pulse related to the transmission of the second physical information itself.

  Hereinafter, a case where two types of physical information X1 and X2 are selectively (alternately) transmitted will be described based on the time chart of FIG. Note that, in the data communication method (communication protocol) of this modification, the second physical information (physical information X1, X2) is transmitted based on the number of consecutive pulses P1, and prior to the transmission of the second physical information. It is assumed that selection information is transmitted based on the number of consecutive pulses P2. Specifically, when the pulse P2 is once, the second physical information transmitted thereafter is the physical information X1 (for example, temperature information), and when the pulse P2 is twice, the second physical information transmitted thereafter. This physical information represents physical information X2 (for example, air pressure information).

  In this case, as shown in FIG. 14, based on the fact that the pulse P2 is once, the fact that the subsequent second physical information is physical information X1 is transmitted as selection information. Then, the physical information X1 is transmitted based on the number of consecutive pulses P1 thereafter. Subsequently, the transmission of the physical information X1 is terminated based on the switching to the pulse P2, and the second physical information thereafter is the physical information X2 based on the fact that the pulse P2 is twice. It is transmitted as selection information. Then, the physical information X2 is transmitted based on the number of consecutive pulses P1 thereafter. As described above, the selection information is transmitted based on the number of consecutive pulses P2 prior to the transmission of the second physical information, so that one type of physical information (X1, X2) corresponding to the selection information is converted into the first information. 2 physical information can be transmitted. Therefore, a plurality of types of physical information as the second physical information can be selectively transmitted through a common signal line L. In particular, a plurality of types of physical information can be selectively transmitted using only two types of pulses P1 and P2. Note that a plurality of types of physical information may be alternately transmitted, or one type of physical information may be weighted and transmitted centrally.

  In the first embodiment, new acquisition of the second physical information (additional information X) may be performed within a predetermined number of times that the pulse P1 is generated. Even if it deform | transforms in this way, 2nd physical information can be updated intermittently.

  In the first embodiment, the additional information X is acquired within a predetermined time or the like during which the pulse P2 is generated, and the second physical information (additional information X) is obtained based on the number of successive pulses P1. It may be transmitted.

In the first embodiment, the pulse related to the transmission of the additional information X may be, for example, a pulse with a changed pulse width (see FIG. 11).
In the second and third embodiments, when the update of the additional information Xs based on the increase / decrease information (output signals Fa to Fc) is estimated to be delayed (for example, the difference value is “−1” continuously for a certain period or In the case of “1”), the current additional information X (Xs) may be transmitted again.

  -In each said embodiment, as 2nd physical information (additional information X), the lateral force applied to the wheel 9 estimated based on the deviation between the peaks P of a mountain side and a valley side, for example may be sufficient. .

  X ... additional information (second physical information), X1, X2 ... physical information (second physical information), L ... signal line, 3 ... periodic signal generation unit, 4 ... output unit (signal processing unit), 5 ... Additional signal generation unit (signal processing unit).

Claims (7)

In the data communication method for transmitting the first physical information representing the speed information by the period of the pulse,
Second physical information different from the first physical information is obtained based on the number of consecutive one type of the pulses by a plurality of types of pulses having a period of the pulse selectively generated based on the pulses. A data communication method comprising: transmitting and terminating transmission of the second physical information based on switching to another type of the pulse different from the one type of the pulse. The data communication method according to claim 1,
The data communication method, wherein the plurality of types of pulses are generated by superimposing other pulses on a high level or low level period of the original pulse. The data communication method according to claim 1,
The data communication method according to claim 1, wherein the plurality of types of pulses are generated by changing a high-level or low-level period of the original pulse. In the data communication method according to any one of claims 1 to 3,
The second physical information is repeatedly transmitted each time the other type of the pulse is generated reaches a predetermined time or the number of generations of the other type of the pulse reaches a predetermined number of times.
The second physical information is acquired within the predetermined time during which the other type of the pulse is generated or within the predetermined number of times when the other type of the pulse is generated. Method. In the data communication method according to any one of claims 1 to 3,
The second physical information is any one type of physical information that can be selected from a plurality of types,
One type of physical information that can be selected from the plurality of types based on the number of consecutive pulses of another type different from the one type of pulses prior to transmission of the second physical information A data communication method characterized by transmitting the selection information. In the data communication method according to any one of claims 1 to 3,
A data communication method characterized by transmitting increase / decrease information of the second physical information for each cycle by the other type of the pulse that is switched after the transmission of the second physical information is completed. Based on a detection signal output from the speed sensor, a periodic signal generator that generates a pulse having a period according to the first physical information representing the speed information;
Based on the pulse, one type of the pulse having a period of the pulse is continuously generated at a number of times corresponding to second physical information different from the first physical information, and the one type of the pulse is generated. A data communication apparatus comprising: a signal processing unit that switches to another type of pulse different from a pulse and outputs the pulse to a signal line.

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