JP2004096217A - Communication system and communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus which makes outputted data signals correctly determined at the receive side. <P>SOLUTION: The communication system 11 comprises a transmitter 12 and a receiver 13 as a communication apparatus and they are communicably connected through a communication medium 14. The transmitter 12 outputs a transmission signal TX and the receiver 13 receives a reception signal RX through the communication medium 14 which is e.g. an optical fiber causing the reception signal RX to be distorted against the transmission signal TX. The transmitter 12 comprises a pulsewidth adjusting circuit 23 which adjusts and outputs the pulsewidth of the transmission signal TX so that a distorted waveform of the reception signal RX due to the communication medium 14 may approximate to an ideal waveform. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a communication device and a communication method.
In recent years, data communication between a plurality of devices has been required to increase the data transfer amount and increase the transfer speed, and so-called optical communication using an optical fiber as a communication medium has been used. . There is a demand for improved reliability in this optical communication.
[0002]
[Prior art]
Conventionally, as shown in FIG. 11, a data communication system 1 includes a transmission device 2 and a reception device 3 as communication devices, and both devices 2 and 3 are connected via a communication medium 4. The transmission device 2 includes a transmission circuit 5, and the transmission circuit 5 transmits a transmission signal (optical pulse signal) S1 having a pulse width corresponding to a bit rate.
[0003]
The receiving device 3 includes a receiving circuit 6, which samples a received signal (received pulse light) RX received via the communication medium 4 based on a clock signal having a frequency corresponding to a bit rate, and receives received data. Generate.
[0004]
[Problems to be solved by the invention]
In the communication system as described above, for example, pulse width distortion (jitter) occurs in received data on the receiving side due to a difference in on / off time characteristics of the communication medium 4. This pulse width distortion causes errors in the received data.
[0005]
For example, as shown in FIG. 12, the transmission circuit 5 outputs a transmission signal TX having a level corresponding to the transmission data and a predetermined (100 ns (nanosecond)) pulse width. As shown in the figure, when transmitting the transmission data “1, 0”, the transmission circuit 5 holds the transmission signal TX at the H level for 100 ns and holds the transmission signal TX at the L level for the next 100 ns. In the transmission signal TX, the rising edge is greatly delayed from the falling edge due to the on / off time characteristic of the communication medium 4. For example, at the receiving device 3 end, the communication medium 4 delays the rising edge by 75 ns and the falling edge by 12.5 ns. As a result, the H level pulse width of the reception signal RX becomes 37.5 ns (the L level pulse width is 162.5 ns).
[0006]
The receiving circuit 6 synchronizes the falling edge of the communication clock signal RCK having substantially the same cycle as the pulse width of the transmission signal TX with the rising edge of the reception signal RX in order to determine the reception data. Then, the receiving circuit 6 determines the level of the received signal RX in response to the rising edge of the communication clock signal RCK, and outputs “1” or “0” received data according to the determination result.
[0007]
In the case where no distortion occurs in the reception signal RX, by using the communication clock signal RCK having substantially the same cycle as the pulse width of the transmission signal TX, it is possible to obtain substantially the same reception data as the transmission data. However, since the pulse width of the H level of the reception signal RX is narrower than the pulse width of the communication clock signal RCK, the reception circuit 6 outputs the reception data “0,0”.
[0008]
As described above, there is a problem that the jitter of the pulse width generated in the transmission path causes an error in the received data.
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a communication device and a communication method capable of correctly determining an output data signal on a receiving side.
[0009]
[Means for Solving the Problems]
In order to solve the above object, the invention according to claim 1 is a communication device that transmits a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium, A pulse width adjustment circuit that adjusts a pulse width of the transmission signal so that a waveform of the reception signal in the reception device approaches an ideal waveform.
[0010]
The invention according to claim 2 is a communication device that transmits a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium, wherein the reception signal with respect to the transmission signal is transmitted. And a pulse width adjustment circuit for adjusting the pulse width of the transmission signal so as to eliminate the waveform distortion.
[0011]
The invention according to claim 3 further includes a transmission circuit that generates a pulse signal having a waveform close to an ideal waveform based on transmission data, and the pulse width adjustment circuit adjusts a pulse width of the pulse signal. .
[0012]
The invention according to claim 4 is characterized in that the pulse width adjustment circuit includes a delay circuit that generates a delay signal obtained by delaying the pulse signal according to the reception signal, and combines the delay signal and the pulse signal. Thus, the transmission signal is generated.
[0013]
According to a fifth aspect of the present invention, the pulse width adjustment circuit generates a plurality of signals having different delay times from the pulse signal, and outputs one of the plurality of signals as a delay signal based on a selection signal. A first width adjustment signal having a pulse width longer than the pulse width of the pulse signal, and a pulse width shorter than the pulse width of the pulse signal. A signal generation circuit for generating a second width adjustment signal having the signal; and a selection circuit for outputting the first or second width adjustment signal as the transmission signal based on the selection signal.
[0014]
The invention according to claim 6 is provided with a storage circuit for storing pulse adjustment information, wherein the pulse width adjustment circuit adjusts the pulse width of the transmission signal based on the pulse adjustment information stored in the storage circuit. I made it.
[0015]
The invention according to claim 7, further comprising a storage circuit for storing pulse width adjustment information corresponding to each of the plurality of connected receiving devices, wherein the pulse width adjustment circuit stores the pulse adjustment information stored in accordance with the transmission destination. The pulse width of the transmission signal to be transmitted to the destination is adjusted based on the information.
[0016]
In the invention described in claim 8, the pulse width adjustment circuit outputs a pulse signal in which a pulse width of a reception signal received via the communication medium is adjusted, to a reception circuit that generates reception data.
[0017]
The invention according to claim 9 includes a detection circuit that detects a waveform distortion of a reception signal received via the communication medium, wherein the pulse width adjustment circuit detects the waveform of the transmission signal based on a detection result of the detection circuit. The pulse width was adjusted.
[0018]
The invention according to claim 10 is a communication method for transmitting a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium, wherein the reception signal The pulse width of the transmission signal is adjusted so that the waveform approaches an ideal waveform.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
[0020]
FIG. 1 is a schematic configuration diagram of a communication system.
The communication system 11 includes a transmission device 12 and a reception device 13 as communication devices, which are communicably connected by a communication medium 14. The transmission device 12 outputs the transmission signal TX, and the reception device 13 receives the reception signal RX via the communication medium 14. The communication medium 14 is, for example, an optical fiber, and causes a distortion in the reception signal RX with respect to the transmission signal TX. The transmission device 12 of the present embodiment generates the transmission signal TX so that the waveform of the reception signal RX in the reception device 13 does not cause a reception error in the reception device 13.
[0021]
The transmission device 12 includes a CPU 21, a transmission circuit 22, and a pulse width adjustment circuit 23.
The CPU 21 outputs transmission data Dt to be transmitted to the receiving device 13 to the transmission circuit 22. The transmission circuit 22 outputs a pulse signal S1 generated according to the transmission data Dt, using a communication clock signal having a frequency corresponding to the communication rate.
[0022]
The pulse width adjustment circuit 23 generates a transmission signal TX whose pulse width has been adjusted from the pulse signal S1. The pulse width adjustment circuit 23 adjusts the pulse width so that the reception side has a desired waveform. It is desirable that the desired waveform is close to an ideal waveform having no distortion in the communication medium 14 (= a waveform having a pulse width defined in the communication protocol). Note that the desired waveform may be any waveform that has no decoding error in the receiving device 13. That is, the transmitting device 12 adjusts the pulse width in advance so that there is no error in the receiving device 13 before transmitting.
[0023]
The receiving device 13 includes a receiving circuit 25 and a CPU 26. The reception circuit 25 outputs the reception data Dr generated by sampling the reception signal RX with a communication clock signal having a frequency corresponding to the communication rate to the CPU 26.
[0024]
Next, the configuration of the transmission device 12 will be described.
FIG. 2 is a partial block circuit diagram of the transmission device 12, showing a detailed circuit configuration of the pulse width adjustment circuit.
[0025]
The transmission device 12 includes an oscillation circuit 31, a frequency divider 32, a transmission circuit 22, and a pulse width adjustment circuit 23.
The oscillation circuit 31 generates an operation clock signal CLK of the transmitting device 12. The frequency divider 32 divides the operation clock signal CLK to generate a communication clock signal TCK having a pulse width corresponding to a communication rate. For example, as shown in FIG. 3, the frequency divider 32 divides the operation clock signal CLK by 8 to generate a communication clock signal TCK having a cycle of 100 ns (nanosecond).
[0026]
In response to the communication clock signal TCK, the transmission circuit 22 outputs a pulse signal S1 generated based on the transmission data Dt input from the CPU 21 to the pulse width adjustment circuit 23. As shown in FIG. 3, the transmission circuit 22 generates an H-level pulse signal S1 when the transmission data Dt is “1”, and generates an L-level pulse signal S1 when the transmission data Dt is “0”. I do. The pulse width of each level is 100 ns based on the cycle of the communication clock signal TCK.
[0027]
The pulse width adjustment circuit 23 includes a storage circuit 33, a delay circuit 34, an AND circuit 35, an OR circuit 36, and a selection circuit (selector) 37.
The pulse adjustment information set in advance is stored in the storage circuit 33. The pulse width adjustment information includes width information, activation information, and length information.
[0028]
The width information is information for adjusting the pulse width, and has a desired waveform on the receiving side by an experiment or the like in advance (for example, a signal received on the receiving side is a pulse width determined by the communication protocol). (A pulse width adjustment amount) set according to the communication medium 14 as described above. That is, in the pulse width adjustment circuit 23, information for adjusting the pulse width according to the transmission state of the communication medium 14 or the like is set in advance.
[0029]
The activation information is information in which whether or not the pulse width of the output transmission signal TX is adjusted in the transmission device 12 is set. That is, the pulse width adjustment circuit 23 sets whether to output the unadjusted transmission signal TX or the pulse width adjusted transmission signal TX based on the set activation information.
[0030]
The length information is information indicating a direction in which the pulse width of the transmission signal TX is adjusted. Depending on the communication medium 14, the pulse width of the reception signal RX may be longer or shorter than the pulse width of the transmission signal TX. Therefore, when the pulse width of the reception signal RX is shorter than that of the transmission signal TX, the pulse width of the transmission signal TX needs to be increased by the pulse width adjustment circuit 23 in advance. On the other hand, when the pulse width of the reception signal RX is longer than that of the transmission signal TX, the pulse width of the transmission signal TX needs to be shortened in advance by the pulse width adjustment circuit 23. Therefore, the pulse width adjustment circuit 23 stores the direction in which the pulse width is adjusted in the storage circuit 33, so that the pulse width of the transmission signal TX can be adjusted to be longer and shorter than that of the pulse signal S1. are doing.
[0031]
The storage circuit 33 generates a first selection signal SL1 based on the width information, and generates a second selection signal SL2 based on the invalidation information and the length information. The first selection signal SL1 is composed of a signal having the number of bits corresponding to the width information, and the second selection signal SL2 is composed of a signal having the number of bits corresponding to the invalidation information and the length information.
[0032]
The operation clock signal CLK and the pulse signal S1 are input to the delay circuit 34. Further, the first selection signal SL1 is input to the delay circuit 34 from the storage circuit 33. The delay circuit 34 includes a plurality of flip-flop circuits (FF) 38a, 38b,..., 38n, and a selection circuit (selector) 39.
[0033]
The FFs 38a to 38n are connected in series, and an operation clock signal CLK is input to each of the FFs 38a to 38n. The pulse signal S1 is input to the first-stage FF 38a. Further, output terminals of the FFs 38 a to 38 n are connected to the selection circuit 39.
[0034]
Each of the FFs 38a to 38n outputs a signal having the same level as the input signal in response to a rising edge of the operation clock signal CLK. Therefore, when the level of the pulse signal S1 changes, each of the FFs 38a to 38n changes the level of the output signal at the rising edge of the operation clock signal CLK in order from the first stage FF. That is, each of the FFs 38a to 38n outputs a signal obtained by sequentially delaying the pulse signal S1 in response to the operation clock signal CLK. The signals output from the FFs 38a to 38n are referred to as delay signals DSa to DSn. Since each of the delay signals DSa to DSn delays the pulse signal S1, as shown in FIG. 3, it has the same pulse width as the pulse signal S1. FIG. 3 shows only the delay signals DSa and DSb.
[0035]
The selection circuit 39 receives a plurality of delay signals DSa to DSn and a first selection signal SL1. The selection circuit 39 outputs a signal corresponding to the selection signal SL1 among the plurality of delay signals DSa to DSn as the selection delay signal DS1 in response to the first selection signal SL1. Since the delay signal DS1 is one of the delay signals DSa to DSn, it has the same pulse width as the pulse signal S1, like the delay signals DSa to DSn.
[0036]
Therefore, the delay circuit 34 generates a plurality of delay signals obtained by delaying the pulse signal S1 in response to the operation clock signal CLK. Then, the delay circuit 34 selects one of the generated delay signals in response to the first selection signal SL1, and outputs the selected delay signal DS1. That is, the delay circuit 34 outputs a delay signal DS1 obtained by delaying the pulse signal S1 by the number of clocks corresponding to the selection signal SL1. For example, as shown in FIG. 3, the delay circuit 34 selects the delay signal DSb in response to the first selection signal SL1, and outputs a delay signal DS1 having substantially the same waveform as the delay signal DSb.
[0037]
The AND circuit 35 outputs a first width adjustment signal S2 generated by performing an AND operation on the input pulse signal S1 and the delay signal DS1. The OR circuit 36 outputs a second width adjustment signal S3 generated by performing an OR operation on the input pulse signal S1 and the delay signal DS1. The delay signal DS1 is delayed from the pulse signal S1 by the number of pulses of the operation clock signal CLK corresponding to the first selection signal SL1, and has the same pulse width as the pulse signal S1. Therefore, as shown in FIG. 3, the pulse width of the first width adjustment signal S2 is shorter than the pulse width of the pulse signal S1 by the number of pulses, and the pulse width of the second width adjustment signal S3 is the pulse width of the pulse signal S1. Longer than the number of pulses.
[0038]
The selection circuit 37 receives the pulse signal S1, the first and second width adjustment signals S2 and S3, and the second selection signal SL2. The selection circuit 37 outputs one selected from the pulse signal S1 and the first and second width adjustment signals S2 and S3 as the transmission signal TX in response to the second selection signal SL2. For example, the selection circuit 37 outputs a transmission signal TX having substantially the same waveform as the second width adjustment signal S3 in response to the second selection signal SL2.
[0039]
That is, the AND circuit 35 and the OR circuit 36 combine the pulse signal S1 and the delay signal DS1, and form a first width adjustment signal S2 having a pulse width shorter than the pulse width of the pulse signal S1 and a pulse width longer than that. And a signal generation circuit for generating the second width adjustment signal S3. Then, the selection circuit 37 outputs one selected from the pulse signal S1 and the first and second width adjustment signals S2 and S3 as the transmission signal TX in response to the second selection signal SL2.
[0040]
Therefore, the delay circuit 34 generates a plurality of delay signals obtained by delaying the pulse signal S1 in response to the operation clock signal CLK. Then, the delay circuit 34 selects one of the generated delay signals in response to the first selection signal SL1, and outputs the selected delay signal DS1. That is, the delay circuit 34 outputs a delay signal DS1 obtained by delaying the pulse signal S1 by the number of clocks corresponding to the selection signal SL1.
[0041]
That is, the pulse width adjustment circuit 23 configured as described above adjusts the pulse width (long or short) according to the width information stored in the storage circuit 33 when adjusting the pulse width based on the activation information. The adjusted transmission signal TX is output. On the other hand, when the pulse width is not adjusted based on the activation information, the transmission signal TX having substantially the same pulse width as the input pulse signal S1 is output.
[0042]
Next, the operation of the transmission device 12 configured as described above will be described with reference to FIG. Now, a signal is transmitted from the transmitting device 12 to the receiving device 13 via the communication medium 14. This communication medium 14 causes distortion in the signal waveform as in the conventional example. That is, in the reception signal RX with respect to the transmission signal TX, the rising edge is delayed by 75 ns and the falling edge is delayed by 12.5 ns.
[0043]
In response to this distortion, the pulse width adjustment circuit 23 transmits the transmission signal TX whose pulse width has been adjusted based on the pulse adjustment information stored in the storage circuit 33 in advance. Specifically, the pulse width adjustment circuit 23 generates a transmission signal TX in which the pulse width of the H level “1” is changed to 162.5 ns from the pulse signal S1 having a pulse width of 100 ns.
[0044]
The receiving device 13 receives the reception signal RX in which the transmission signal TX has passed through the communication medium 14. The reception signal RX has a shorter pulse width at the H level than the transmission signal TX, and the pulse width is 100 ns (= 162.5−75 + 12.5).
[0045]
The receiving device 13 decodes the received signal RX with a communication clock signal RCK having a specified period (pulse width). This communication clock signal RCK has the same cycle (H level pulse width is 50 ns) as the communication clock signal TCK used when the transmission circuit 22 of the transmission device 12 generates the pulse signal S1. The receiving device 13 synchronizes the falling edge of the communication clock signal RCK with the rising edge of the reception signal RX, and outputs reception data having a value corresponding to the level of the reception signal RX at the rising edge of the communication clock signal RCK. The H-level pulse width of the reception signal RX is 100 ns because the H-level pulse width of the transmission signal TX is adjusted by the transmission device 12, which is longer than the conventional one (37.5 ns). It is longer than 1/2 of the period of RCK. For this reason, the receiving device 13 outputs the received data whose value is “1” in response to the rising edge of the communication clock signal RCK. As described above, in the communication system 11, even when the communication medium 14 that causes waveform distortion is used, no communication error occurs. That is, the transmission device 12 prevents the occurrence of a reception error in the reception device 13 by adjusting the pulse width of the transmission signal TX in advance.
[0046]
As described above, the present embodiment has the following advantages.
(1) The pulse width adjusting circuit 23 is provided, and the pulse width of the transmission signal TX is adjusted and output so that the waveform of the reception signal RX in which the communication medium 14 causes waveform distortion approaches an ideal waveform. As a result, the occurrence of a reception error in the receiving device 13 can be suppressed.
[0047]
(2) The pulse width adjustment circuit 23 is configured to be able to output the transmission signal TX whose pulse width has not been adjusted in response to the second selection signal SL2. Therefore, it is possible to easily cope with a communication medium that does not cause waveform distortion.
[0048]
(3) The delay circuit 34 provided in the pulse width adjustment circuit 23 generates a plurality of delay signals DSa to DSn having different delay times from the pulse signal S1, and generates a delay signal selected in response to the first selection signal SL1. Output as the selection delay signal DS1. Then, the pulse signal and the selection delay signal DS1 are combined by the signal generation circuit, and the transmission signal TX whose pulse width is adjusted is output. Therefore, the pulse width of the transmission signal TX can be easily adjusted. Further, the pulse width of the transmission signal TX can be easily changed.
[0049]
(Second embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
For convenience of explanation, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is partially omitted.
[0050]
FIG. 5 is a partial block circuit diagram of the transmission device 41, and shows a detailed circuit configuration of the pulse width adjustment circuit.
This transmitting device 41 is replaced with the transmitting device 12 of FIG. 1 to constitute a communication system.
[0051]
The transmission device 41 includes an oscillation circuit 31, a frequency divider 32, a transmission circuit 22, a pulse width adjustment circuit 42, and a storage circuit 43.
The storage circuit 43 provides substantially the same function as the storage circuit 33 of the first embodiment. That is, the storage circuit 43 stores preset pulse adjustment information. The pulse width adjustment information includes width information, activation information, and length information. The storage circuit 43 generates a first selection signal SL1 based on the width information, and generates a second selection signal SL2 based on the invalidation information and the length information. Then, the first and second selection signals SL1 and SL2 generated by the storage circuit 43 are output to the pulse width adjustment circuit 42.
[0052]
The pulse width adjustment circuit 42 receives the pulse signal S1, the operation clock signal CLK, and the first and second selection signals SL1 and SL2. The pulse width adjustment circuit 42 includes a delay circuit 34, an AND circuit 35, an OR circuit 36, and a selection circuit (selector) 37. The first and second selection signals SL1 and SL2 from the storage circuit 43 are used to select the delay circuit 34 Selector 39) and selector 37. Therefore, the pulse width adjustment circuit 42 and the storage circuit 43 of the present embodiment provide substantially the same function as the pulse width adjustment circuit 23 of the first embodiment.
[0053]
That is, the pulse width adjusting circuit 42 adjusts the pulse width from the pulse signal S1 in response to the first and second selection signals SL1 and SL2 supplied from the outside, or adjusts the pulse width substantially equal to the pulse signal S1. The transmission signal TX is output.
[0054]
As described above, the present embodiment has the following advantages.
(1) The pulse width adjustment circuit 42 responds to the first and second selection signals SL1 and SL2 supplied from the storage circuit 43, and adjusts the pulse width based on the pulse signal S1, or is substantially equal to the pulse signal S1. , A transmission signal TX having the same pulse width is output. As the storage circuit 43, a part of a memory (buffer) or the like that temporarily stores transmission data can be used, and the degree of freedom of the circuit configuration can be increased. Further, by using a part of a memory such as a buffer as the storage circuit 43, a peripheral circuit of the storage circuit 43 (a circuit configuration for accessing the storage circuit 43 provided in the pulse width adjustment circuit 42) can be omitted. Thus, the circuit scale of the transmission device can be reduced.
[0055]
(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.
For convenience of explanation, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is partially omitted.
[0056]
FIG. 6 is a schematic configuration diagram of the communication system.
The communication system 51 includes a transmission device 52 and a reception device 13 as communication devices, which are connected by a communication medium 14.
[0057]
The transmission device 52 includes a CPU 53, a transmission circuit 22, and a pulse width adjustment circuit 42.
The CPU 53 outputs the transmission data Dt to be transmitted to the receiving device 13 to the transmission circuit 22. Further, the CPU 53 outputs the first and second selection signals SL1 and SL2 to the pulse width adjustment circuit 42.
[0058]
The transmission circuit 22 outputs a pulse signal S1 generated according to transmission data generated by a communication clock signal having a frequency corresponding to the communication rate.
The pulse width adjustment circuit 42 adjusts the pulse width from the pulse signal S1 in response to the first and second selection signals SL1 and SL2 supplied from the CPU 53, or transmits the pulse having substantially the same pulse width as the pulse signal S1. The signal TX is output.
[0059]
The CPU 53 generates the first and second selection signals SL1 and SL2 so as to change the pulse width of the transmission signal TX. The change of the pulse width is performed, for example, according to the operating environment. That is, if the characteristics of the communication medium 14 change due to the environment (ambient temperature) in which the communication system operates, the adjustment of the pulse width becomes unnecessary, or the adjustment of the pulse width becomes insufficient with the predetermined pulse adjustment information (width information). There are cases.
[0060]
For this reason, the CPU 53 detects the environmental temperature with the temperature sensor, determines the value of the pulse width to be adjusted according to the detection result, and generates the first and second selection signals SL1 and SL2 according to the determination result. .
[0061]
The pulse width adjustment circuit 42 adjusts the pulse width from the pulse signal S1 in response to the first and second selection signals SL1 and SL2 supplied from the CPU 53, or transmits the pulse having substantially the same pulse width as the pulse signal S1. The signal TX is output.
[0062]
The receiving device 13 decodes the received signal RX received via the communication medium 14. At this time, the characteristics of the communication medium 14 change to characteristics according to the environmental temperature. The CPU 53 generates the first and second selection signals SL1 and SL2 so as to change the pulse width of the transmission signal TX so that no error occurs in the receiving device 13 according to the changing characteristics. The amount of change in the characteristics of the communication medium 14 is obtained in advance through experiments or the like (digitized), and is stored in the internal memory of the CPU 53 or program data for communication. The CPU 53 generates the first and second selection signals SL1 and SL2 based on the quantified amount of change.
[0063]
In this communication system 11, no communication error occurs even if the characteristics of the communication medium 14 change. That is, the transmission device 12 prevents the occurrence of a reception error in the reception device 13 by adjusting the pulse width of the transmission signal TX in advance.
[0064]
As described above, the present embodiment has the following advantages.
(1) The CPU 53 outputs the transmission data Dt to the transmission circuit 22 and outputs the first and second selection signals SL1 and SL2 to the pulse width adjustment circuit 42. As a result, there is no need to provide a storage circuit, and the circuit scale of the transmission device 52 can be reduced accordingly.
[0065]
(2) The CPU 53 outputs the first and second selection signals SL1 and SL2 to the pulse width adjustment circuit 42. As a result, the pulse width of the transmission signal TX can be easily changed.
[0066]
(Fourth embodiment)
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIGS.
Note that, for convenience of description, the same components as those of the first to third embodiments are denoted by the same reference numerals, and the description thereof is partially omitted.
[0067]
FIG. 7 is a schematic configuration diagram of a communication system.
The communication system 61 includes a transmitting device 62 and a plurality of (two in the present embodiment) receiving devices 13a and 13b as communication devices. The transmitting device 62 and the first receiving device 13a are communicably connected via a first communication medium 63a, and the transmitting device 62 and the second receiving device 13b are communicably connected via a second communication medium 63b. The first and second communication media 63a and 63b are made of, for example, optical fibers. The connection between the transmitting device 62 and each of the receiving devices 13a and 13b is not limited to a configuration in which each of the receiving devices 13a and 13b is connected via the communication medium 63a and 63b, but may be a distributor such as a hub or an optical fiber. Alternatively, a connection mode using a one-to-many (1 × n) coupler may be used.
[0068]
The transmission device 62 outputs the transmission signal TX, and the first reception device 13a receives the first reception signal RXa via the first communication medium 63a. Further, the transmission device 62 outputs the transmission signal TX, and the second reception device 13b receives the second reception signal RXb via the second communication medium 63b.
[0069]
The first and second communication media 63a and 63b cause distortion in the first and second reception signals RXa and RXb with respect to the transmission signal TX due to their respective characteristics. The transmission device 62 of the present embodiment generates the transmission signal TX so that the waveforms of the reception signals RXa and RXb in the reception devices 13a and 13b do not cause a reception error in the reception devices 13a and 13b.
[0070]
The transmitting device 62 includes a CPU 64, a transmitting circuit 22, and a pulse width adjusting circuit 65.
The CPU 64 outputs the transmission data Dt to be transmitted to the first or second receiving device 13a, 13b to the transmitting circuit 22. Further, the CPU 64 outputs a device selection signal SLT to the pulse width adjustment circuit 65.
[0071]
The transmission circuit 22 outputs a pulse signal S1 generated according to the transmission data Dt to the pulse width adjustment circuit 65 by using a communication clock signal having a frequency corresponding to the communication rate.
[0072]
The pulse width adjustment circuit 65 generates a transmission signal TX whose pulse width has been adjusted from the pulse signal S1. At this time, the pulse width adjusting circuit 65 adjusts the pulse width based on the device selection signal SLT so that the receiving side has a desired waveform corresponding to each of the receiving devices 13a and 13b. It is desirable that the desired waveform is close to an ideal waveform having no distortion in the first and second communication media 63a and 63b. Note that the desired waveform may be any waveform that has no decoding error in the first and second receiving devices 13a and 13b. That is, the transmitting device 62 adjusts the pulse width of the transmission signal TX in advance so that the first and second receiving devices 13a and 13b have no error, and transmits the signal.
[0073]
The first receiving device 13a includes a receiving circuit 25a and a CPU 26a. The reception circuit 25a outputs the reception data Dra generated by sampling the reception signal RXa with a communication clock signal having a frequency corresponding to the communication rate to the CPU 26a. The second receiving device 13b includes a receiving circuit 25b and a CPU 26b. The reception circuit 25b outputs the reception data Drb generated by sampling the reception signal RXb with a communication clock signal having a frequency corresponding to the communication rate to the CPU 26b.
[0074]
Next, the configuration of the transmitting device 62 will be described.
FIG. 8 is a partial block circuit diagram of the transmission device 62, and shows a detailed circuit configuration of the pulse width adjustment circuit.
[0075]
The transmitting device 62 includes a CPU 64, a transmitting circuit 22, and a pulse width adjusting circuit 65. Although not shown, the transmission device 62 includes an oscillation circuit 31 and a frequency divider 32, and generates an operation clock signal CLK and a communication clock signal TCK, as in the first embodiment.
[0076]
The pulse width adjustment circuit 65 includes a first storage circuit 66a, a second storage circuit 66b, a delay circuit 34, an AND circuit 35, an OR circuit 36, and a selection circuit (selector) 37.
The first storage circuit 66a stores first pulse adjustment information set in advance corresponding to the first receiving device 13a, and the pulse width adjustment information includes width information, activation information, and length information. Including. The first pulse adjustment information does not cause an error in the first reception data Dra based on each reception signal RXa in the first reception device 13a, that is, cancels the distortion generated in the first reception signal RXa by the first communication medium 63a. The information is set as follows. The first storage circuit 66a generates a first selection signal SL1a based on the width information, and generates a second selection signal SL2a based on the invalidation information and the length information. The first selection signal SL1a is composed of a signal having the number of bits corresponding to the width information, and the second selection signal SL2a is composed of a signal having the number of bits corresponding to the invalidation information and the length information.
[0077]
Similarly, the second storage circuit 66b stores second pulse adjustment information set in advance corresponding to the second receiving device 13b, and the pulse width adjustment information includes width information, activation information, and length information. Including information. The second pulse adjustment information does not cause an error in the second reception data Drb based on each reception signal RXb in the second reception device 13b, that is, cancels the distortion generated in the second reception signal RXb by the second communication medium 63b. The information is set as follows. The second storage circuit 66b generates a first selection signal SL1b based on the width information, and generates a second selection signal SL2b based on the invalidation information and the length information. The first selection signal SL1b is composed of a signal having the number of bits corresponding to the width information, and the second selection signal SL2b is composed of a signal having the number of bits corresponding to the invalidation information and the length information.
[0078]
The CPU 64 generates the device selection signal SLT according to the transmission destination of the transmission data Dt so as to adjust the pulse width of the transmission signal TX based on the transmission data Dt. That is, since the first and second communication media 63a and 63b have different ON / OFF characteristics, the distortion generated in the first reception signal RXa and the distortion generated in the second reception signal RXb with respect to the transmission signal TX are different. Accordingly, the CPU 64 generates the device selection signal SLT based on whether the transmission destination of the transmission signal TX is the first or second receiving device 13a or 13b. For example, the CPU 64 outputs an H-level device selection signal SLT when the transmission destination is the first receiving device 13a, and outputs an L-level device selection signal SLT when the transmission destination is the second receiving device 13b.
[0079]
The first storage circuit 66a is activated in response to the device selection signal SLT at the H level, and is deactivated in response to that at the L level. Conversely, the second storage circuit 66b is activated in response to the L-level device selection signal SLT, and is deactivated in response to the H-level device selection signal SLT. The activated first storage circuit 66a or the second storage circuit 66b outputs a first selection signal and a second selection signal based on the pulse adjustment information stored respectively.
[0080]
When there are three or more receiving devices, it is effective to use a plurality of bits as the device selection signal SLT. The CPU 64 generates a device selection signal SLT in which only the bit corresponding to the transmission destination is set at the H level (or the L level). Each receiving device is activated or deactivated according to the level of the corresponding bit, and one activated receiving device outputs the first and second selection signals.
[0081]
Therefore, the pulse width adjusting circuit 65 of the present embodiment outputs the transmission signal TX whose pulse width has been adjusted according to each of the connected receiving devices 13a and 13b, specifically, each of the communication media 63a and 63b. Therefore, no error occurs in the received data Dra, Drb obtained by decoding the received signals RXa, RXb in the receiving devices 13a, 13b.
[0082]
As described above, the present embodiment has the following advantages.
(1) Since the pulse width of the transmission signal TX is adjusted in the transmission device 62 so that the reception signals RXa and RXb of the reception devices 13a and 13b have ideal waveforms, a circuit for correcting errors in the reception devices 13a and 13b May not be provided. Therefore, no countermeasure is required on the receiving side, and the cost of the entire communication system 61 can be reduced.
[0083]
(Fifth embodiment)
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIGS. For convenience of description, the same components as those in the first to fourth embodiments are denoted by the same reference numerals, and the description thereof is partially omitted.
[0084]
FIG. 9 is a schematic configuration diagram of a communication system.
The communication system 71 has a plurality of (two in FIG. 9) data communication devices 72 and 73 communicably connected via a communication medium 74. The communication devices 72 and 73 are configured to be able to transmit and receive, respectively.
[0085]
That is, the first communication device 72 includes a CPU 81, a transmission circuit 82, a pulse width adjustment circuit 83, and a reception circuit 84, and the second communication device 73 includes a reception circuit 85, a CPU 86, and a transmission circuit 87.
[0086]
The CPU 81 outputs transmission data Dta to be transmitted to the second communication device 73 to the transmission circuit 82. The transmission circuit 82 outputs a pulse signal S1t generated according to the transmission data Dta by a communication clock signal having a frequency corresponding to the communication rate.
[0087]
The pulse width adjustment circuit 83 generates a transmission signal TXa whose pulse width has been adjusted from the pulse signal S1t. The pulse width adjustment circuit 83 adjusts the pulse width so that the reception side has a desired waveform. It is desirable that the desired waveform is close to an ideal waveform having no distortion in the communication medium 74. Note that the desired waveform may be any waveform that has no decoding error in the second communication device 73. That is, the transmitting device 12 adjusts the pulse width in advance so that the second communication device 73 has no error, and transmits the adjusted signal.
[0088]
The pulse width adjustment circuit 83 receives the reception signal RXa received from the second communication device 73 via the communication medium 74, and receives the pulse signal S1r in which the pulse width of the reception signal RXa is adjusted according to the communication medium 74. Output to the circuit 84. The receiving circuit 84 outputs the received data Drb generated by sampling the pulse signal S1r using the communication clock signal to the CPU 26.
[0089]
The receiving circuit 85 of the second communication device 73 receives the reception signal RXb received from the first communication device 72 via the communication medium 74, and samples the reception signal RXb with a communication clock signal having a frequency corresponding to the communication rate. The received data Drb thus generated is output to the CPU 86. The CPU 86 outputs the transmission data Dtb to be transmitted to the first communication device 72 to the transmission circuit 87. The transmission circuit 87 transmits the transmission signal TXb generated according to the transmission data Dtb by the communication clock signal.
[0090]
In other words, the pulse width adjustment circuit 83 of the present embodiment uses the first communication device 72 to adjust the pulse width of the input signal (the pulse signal S1t and the reception signal RXa) corresponding to the communication medium 74 at the time of transmission and reception. (The transmission signal TXa and the pulse signal S1r). Therefore, even if the pulse width is not adjusted on the second communication device 73 side, it is possible to suppress the occurrence of an error in the reception between the second communication device 73 and the first communication device 72.
[0091]
FIG. 10 is a block circuit diagram of the pulse width adjustment circuit 83.
The pulse width adjustment circuit 83 includes a detection circuit 91, a storage circuit 92, first and second switch circuits 93 and 94, a delay circuit 34, an AND circuit 35, an OR circuit 36, and a selection circuit 37.
[0092]
The detection signal 91 is input with the reception signal RXa and the communication clock signal TCK. The communication clock signal TCK is a pulse signal having a predetermined cycle (100 ns) as described in the first embodiment. The detection circuit 91 detects the pulse width of the received signal RXa, compares the detection result with the communication clock signal TCK, and calculates pulse adjustment information (width information) corresponding to the communication medium 74.
[0093]
The reception signal RXa is obtained by receiving the transmission signal TXb transmitted from the second communication device 73 shown in FIG. Since the second communication device 73 does not include the pulse width adjustment circuit, the pulse width of the transmission signal TXb is not adjusted, that is, has the same pulse width as the cycle of the communication clock signal TCK. Therefore, the pulse width of the reception signal RXa is affected by the characteristics of the communication medium 74 as compared with the pulse width of the transmission signal TXb.
[0094]
The detection circuit 91 detects the pulse width of the reception signal RXa by sampling. Then, the detection circuit 91 compares the detected pulse width of the reception signal RXa with the cycle of the communication clock signal TCK, and calculates width information for adjusting the pulse width of the transmission signal TXa based on the comparison result. When the pulse width of the reception signal RXa is shorter than half the period of the communication clock signal TCK (50 ns in this embodiment), the pulse width of the reception signal RXb with respect to the transmission signal TXa transmitted from the first communication device 72 is the same. Therefore, a reception error occurs in the second communication device 73.
[0095]
Accordingly, based on the pulse width of the reception signal RXa, the detection circuit 91 detects the transmission signal TXa so that the pulse width of the reception signal RXb in the second communication device 73 is longer than の of the cycle of the communication clock signal TCK. The width information is calculated so as to adjust the pulse width. Then, the detection circuit 91 outputs the calculated width information to the storage circuit 92, and the storage circuit 92 stores the width information. Then, the storage circuit 92 outputs the first selection signal SL1 created based on the stored width information to the selection circuit 37 of the delay circuit 34.
[0096]
The pulse signal S1t or the reception signal RXa is input to the delay circuit 34 via the first switch circuit 93. The switching of the first switch circuit 93 and the second switch circuit 94 is controlled by a transmission / reception switching signal STR from the CPU 81. That is, based on the transmission / reception switching signal STR, at the time of transmission, switching is performed so that the pulse signal S1t is input to the delay circuit 34 and the output signal of the selection circuit 37 is output to the communication medium 74 as the transmission signal TXa. On the other hand, at the time of reception, switching is performed so that the reception signal RXa is input to the delay circuit 34 and the output signal of the selection circuit 37 is supplied to the reception circuit 84 as the pulse signal S1r.
[0097]
That is, the pulse width adjustment circuit 83 outputs a transmission signal TXa having a pulse width adjusted from the input pulse signal S1t based on the pulse information stored in the storage circuit 92, and outputs a pulse width from the input reception signal RXa. Is output as a pulse signal S1r. The pulse width adjustment circuit 83 adjusts the pulse width of the transmission signal TXa in advance so that a reception error does not occur in the second communication device 73 of FIG. A pulse signal S1r whose pulse width is adjusted is generated from RXa.
[0098]
As described above, the present embodiment has the following advantages.
(1) The pulse width adjustment circuit 83 outputs the transmission signal TX whose pulse width has been adjusted from the pulse signal S1t, and outputs the pulse signal S1r whose pulse width has been adjusted from the reception signal RX to the reception circuit 84. As a result, a reception error in the own device 72 can be prevented.
[0099]
(2) The detection circuit 91 detects width information for adjusting the pulse width based on the reception signal RXa, and updates the pulse width information in the storage circuit 92. As a result, it is possible to easily respond to changes in the characteristics of the communication medium 74 and exchange of the communication medium.
[0100]
(3) Each time a signal is received, the detection circuit 91 detects the pulse width of the reception signal RXa and updates the contents (pulse width information) of the storage circuit 92. As a result, even if the on / off characteristics of the communication medium 74 change in accordance with the environment (ambient temperature), the amount of adjustment of the pulse width is changed so as to follow the change, and the communication on the receiving side due to the influence of the environment and the like. A reception error in the device 73 can be prevented.
[0101]
Each of the above embodiments may be implemented in the following manner.
In the fourth embodiment, when the transmission data Dta and Dtb include the information of the transmission destination, the pulse width adjustment circuit 65 determines which of the first storage circuit 66a and the second storage circuit 66b based on the information. May be selected.
[0102]
In the fifth embodiment, similarly to the fourth embodiment, the first communication device 72 and a plurality of communication partners are configured to be communicable, and each communication partner is adjusted so that the pulse width is adjusted for each communication partner. May be provided and implemented. In the first to fifth embodiments, the storage circuit is shown as a circuit functionally for a communication partner, and stores pulse adjustment information corresponding to a plurality of communication partners in one storage circuit. Is also good.
[0103]
In the fifth embodiment, the communication device 72 may appropriately detect pulse width distortion (jitter) based on the received signal RXa. For example, the communication device 72 detects at the time of starting reception (at the time of the first reception). For the detection, for example, the detection circuit 91 includes a register. The register is cleared at the start of operation of the communication device 72 (including at the time of reset), and the detection circuit 91 sets the register when detecting the pulse width, and executes the detection operation when the register is set. do not do. With such a configuration, the detection operation is not performed each time the detection circuit 91 receives a signal, so that power consumption can be reduced accordingly.
[0104]
Note that the detection operation of the detection circuit 91 is performed as necessary. For example, the CPU 81 outputs the clear signal CLR shown in FIG. 10 to the detection circuit 91, and the detection circuit 91 resets the register in response to the clear signal CLR. With this configuration, the pulse width of the transmission signal TXa can be adjusted according to the characteristics of the communication medium 74 while reducing power consumption.
[0105]
In the fifth embodiment, the pulse width adjustment circuit 83 includes the detection circuit 91. However, the pulse width adjustment circuit and the detection circuit may be separately provided.
In the fifth embodiment, the storage circuit 92 that stores the detection result of the detection circuit 91 and generates the first and second selection signals SL1 and SL2 is provided. However, the first and second selection signals SL1 are directly output from the detection circuit. , SL2 may be output. In that case, it is preferable to provide a latch circuit or the like at the output unit of the detection circuit so as to hold the levels of the first and second selection signals SL1 and SL2.
[0106]
In the fifth embodiment, the pulse width adjustment amount for the transmission signal TXa may be different from the pulse width adjustment amount for the reception signal RXa. That is, a transmission storage circuit and a reception storage circuit are provided, and one of them is selected by the transmission / reception switching signal STR. According to this configuration, even when the transmission signal TXb output from the communication device 73 of the communication partner does not have an ideal waveform (has a different pulse width), or when the characteristics of the communication medium 74 are different depending on the communication direction, the first and the second signals are different. The reception signals RXa and Rxb in the second communication devices 72 and 73 can be made closer to ideal waveforms to prevent reception errors.
[0107]
The pulse width adjustment circuits 23, 42, 65, and 83 of the above embodiments have the first width adjustment signal S2 having a longer pulse width at the H level than the pulse signal S1, and the pulse width at the H level than the pulse signal S1. Although the short second width adjustment signal S <b> 3 is generated, a configuration may be employed in which only one of the signals is generated according to the communication medium 14. In this case, one of the AND circuit 35 and the OR circuit 36 can be omitted, and the circuit configurations of the selection circuit 37 and the storage circuit 33 can be reduced, and the occupied area of the pulse width adjustment circuits 23, 42, 65, and 83 can be reduced. Can be reduced.
[0108]
In the above embodiments, the communication devices 12, 52, 62, and 72 include the CPUs 21, 53, 64, and 81, the transmission circuits 22, 82, and the pulse width adjustment circuits 23, 42, 65, and 83. The pulse width of a transmission signal in communication between computers may be adjusted by mounting (removably connecting) a communication board as a communication device on a computer such as a personal computer. That is, the communication board includes a transmission circuit and a pulse width adjustment circuit, and adjusts the pulse width of a transmission signal generated based on transmission data from the CPU of the computer.
[0109]
The features of each of the above embodiments are summarized as follows.
(Supplementary Note 1) A communication device that transmits a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium,
A communication device, comprising: a pulse width adjustment circuit that adjusts a pulse width of the transmission signal so that a waveform of the reception signal in the reception device approaches an ideal waveform. (1)
(Supplementary Note 2) A communication device that transmits a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium,
A communication device comprising: a pulse width adjustment circuit that adjusts a pulse width of the transmission signal so as to eliminate waveform distortion of the reception signal with respect to the transmission signal. (2)
(Supplementary Note 3) A transmission circuit that generates a pulse signal having a waveform close to an ideal waveform based on the transmission data,
3. The communication device according to claim 1, wherein the pulse width adjustment circuit adjusts a pulse width of the pulse signal. (3)
(Supplementary Note 4) The pulse width adjustment circuit includes:
A delay circuit that generates a delay signal in which the pulse signal is delayed according to the reception signal;
4. The communication device according to claim 3, wherein the transmission signal is generated by combining the delay signal and the pulse signal. (4)
(Supplementary note 5) The communication device according to supplementary note 4, wherein the pulse width adjustment circuit is configured to be able to output a transmission signal having the same pulse width as an input pulse signal.
(Supplementary Note 6) The pulse width adjustment circuit includes:
A delay circuit that generates a plurality of signals having different delay times from the pulse signal and outputs one of the plurality of signals as a delay signal based on a selection signal;
A first width adjustment signal having a pulse width longer than the pulse width of the pulse signal; and a second width having a pulse width shorter than the pulse width of the pulse signal. A signal generation circuit for generating an adjustment signal;
A selection circuit that outputs the first or second width adjustment signal as the transmission signal based on the selection signal;
4. The communication device according to claim 3, further comprising: (5)
(Supplementary Note 7) The selection circuit receives first and second width adjustment signals and the pulse signal, and converts one of the pulse signal and the first and second width adjustment signals into the selection signal. 7. The communication device according to claim 6, wherein the communication device selects based on the selected information, and outputs the selected signal as the transmission signal.
(Supplementary Note 8) A storage circuit for storing pulse adjustment information is provided,
8. The communication according to claim 1, wherein the pulse width adjustment circuit adjusts a pulse width of the transmission signal based on pulse adjustment information stored in the storage circuit. 9. apparatus. (6)
(Supplementary Note 9) A storage circuit that stores pulse width adjustment information corresponding to each of the plurality of connected reception devices,
The pulse width adjusting circuit may adjust a pulse width of a transmission signal to be transmitted to the destination based on pulse adjustment information stored according to the destination. Communication device according to one. (7)
(Supplementary note 10) The pulse width adjusting circuit outputs a pulse signal in which a pulse width of a received signal received via the communication medium is adjusted, to a receiving circuit that generates reception data. Communication device according to any one of the above. (8)
(Supplementary Note 11) A detection circuit that detects waveform distortion of a received signal received via the communication medium,
11. The communication device according to claim 1, wherein the pulse width adjustment circuit adjusts a pulse width of the transmission signal based on a detection result of the detection circuit.
(Supplementary Note 12) Supplementary note 8 characterized by comprising a detection circuit that detects waveform distortion of a received signal received via the communication medium and updates pulse adjustment information of the storage circuit based on the detection result. Or the communication device according to 9.
(Supplementary note 13) The communication device according to supplementary note 11 or 12, wherein the detection circuit detects a waveform distortion every time the reception signal is input.
(Supplementary Note 14) A communication method of transmitting a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium,
A communication method, comprising: adjusting a pulse width of the transmission signal so that a waveform of the reception signal in the reception device approaches an ideal waveform. (10)
(Supplementary Note 15) A communication method of transmitting a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium,
A communication method, comprising: adjusting a pulse width of the transmission signal so as to eliminate waveform distortion of the reception signal with respect to the transmission signal.
(Supplementary Note 16) A delay signal is generated by delaying a pulse signal having a waveform close to an ideal waveform based on the transmission data in accordance with the reception signal, and the delay signal and the pulse signal are combined to generate the transmission signal. 16. The communication method according to appendix 14 or 15, wherein the communication method is generated.
(Supplementary Note 17) A plurality of signals having different delay times are generated from a pulse signal having a waveform close to an ideal waveform based on transmission data, and one of the plurality of signals is combined with the pulse signal to generate the pulse signal. Generating a first width adjustment signal having a pulse width longer than the pulse width of the first and second width adjustment signals having a pulse width shorter than the pulse width of the pulse signal. 16. The communication method according to claim 14, wherein a signal is output as the transmission signal.
(Supplementary note 18) The communication method according to any one of Supplementary notes 14 to 17, wherein a pulse signal in which a pulse width of a reception signal received via the communication medium is adjusted is generated.
(Supplementary note 19) Any one of Supplementary notes 14 to 18, wherein a waveform distortion of a reception signal received via the communication medium is detected, and a pulse width of the transmission signal is adjusted based on the detection result. The communication method according to any one of the above.
[0110]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a communication device and a communication method capable of correctly determining an output data signal on a receiving side.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a communication system according to a first embodiment.
FIG. 2 is a circuit diagram of a pulse width adjustment circuit according to the first embodiment.
FIG. 3 is an operation waveform diagram of the pulse width adjustment circuit.
FIG. 4 is an operation waveform diagram of the communication system.
FIG. 5 is a circuit diagram of a pulse width adjustment circuit according to a second embodiment.
FIG. 6 is a schematic configuration diagram of a communication system according to a third embodiment.
FIG. 7 is a schematic configuration diagram of a communication system according to a fourth embodiment.
FIG. 8 is a circuit diagram of a pulse width adjustment circuit according to a fourth embodiment.
FIG. 9 is a schematic configuration diagram of a communication system according to a fifth embodiment.
FIG. 10 is a circuit diagram of a pulse width adjustment circuit according to a fifth embodiment.
FIG. 11 is a schematic configuration diagram of a conventional communication system.
FIG. 12 is an operation waveform diagram of a conventional example.
[Explanation of symbols]
12, 41, 52, 62, 72 Communication device (transmission device)
13, 13a, 13b, 73 receiving device
14, 63a, 63b Communication media
22, 82 transmission circuit
23, 42, 65, 83 pulse width adjustment circuit
84 Receiver circuit
TX, TXa transmission signal
S1 pulse signal

Claims (10)

A communication device that transmits a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium,
A communication device, comprising: a pulse width adjustment circuit that adjusts a pulse width of the transmission signal so that a waveform of the reception signal in the reception device approaches an ideal waveform. A communication device that transmits a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium,
A communication device comprising: a pulse width adjustment circuit that adjusts a pulse width of the transmission signal so as to eliminate waveform distortion of the reception signal with respect to the transmission signal. A transmission circuit that generates a pulse signal having a waveform close to an ideal waveform based on transmission data,
The communication device according to claim 1, wherein the pulse width adjustment circuit adjusts a pulse width of the pulse signal. The pulse width adjustment circuit,
A delay circuit that generates a delay signal in which the pulse signal is delayed according to the reception signal;
The communication device according to claim 3, wherein the transmission signal is generated by combining the delay signal and the pulse signal. The pulse width adjustment circuit,
A delay circuit that generates a plurality of signals having different delay times from the pulse signal and outputs one of the plurality of signals as a delay signal based on a selection signal;
A first width adjustment signal having a pulse width longer than the pulse width of the pulse signal; and a second width having a pulse width shorter than the pulse width of the pulse signal. A signal generation circuit for generating an adjustment signal;
A selection circuit that outputs the first or second width adjustment signal as the transmission signal based on the selection signal;
The communication device according to claim 3, further comprising: A storage circuit for storing pulse adjustment information;
The pulse width adjustment circuit according to claim 1, wherein the pulse width adjustment circuit adjusts a pulse width of the transmission signal based on pulse adjustment information stored in the storage circuit. Communication device. A storage circuit for storing pulse width adjustment information corresponding to each of the plurality of connected receiving devices,
6. The pulse width adjustment circuit according to claim 1, wherein the pulse width adjustment circuit adjusts a pulse width of a transmission signal transmitted to the destination based on pulse adjustment information stored according to the destination. The communication device according to claim 1. 8. The pulse width adjustment circuit according to claim 1, wherein the pulse width adjustment circuit outputs a pulse signal obtained by adjusting a pulse width of a reception signal received via the communication medium to a reception circuit that generates reception data. The communication device according to claim 1. A detection circuit for detecting waveform distortion of a received signal received via the communication medium,
The communication device according to claim 1, wherein the pulse width adjustment circuit adjusts a pulse width of the transmission signal based on a detection result of the detection circuit. A communication method for transmitting a transmission signal to a reception device that generates reception data based on a pulse width of a reception signal received via a communication medium,
A communication method, comprising: adjusting a pulse width of the transmission signal so that a waveform of the reception signal in the reception device approaches an ideal waveform.

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