JP2003110535A - Data communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data communication device, in which exact communication can be implemented by detecting an error without lowering efficiency in the transmission of communication data. SOLUTION: When data D of a fixed quantity are communicated by a decoding method, in which the number of times of sampling per unit time is known and at least two kinds of codes are discriminated by code lengths, the total number of times of sampling N1 is calculated from a data quantity B0 of the data D, codes contained in the data D and the number of times of sampling N per unit time and is compared with the total number of times of receiving sampling N2 in the case of real receiving, so that the error can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication device, and more particularly to error detection during data communication.

[0002]

2. Description of the Related Art A method for detecting an error in data communication is being studied in order to prevent reception of erroneous data. Generally, parity check, check SU
The data transmitter transmits communication data by adding an error detection code to the data so that it belongs to a predetermined set such as M and CRC. On the other hand, in the data receiver, a method of determining whether the received communication data belongs to a predetermined set and detecting a data error is used.

[0003]

However, in the error detecting method in the conventional data communication apparatus, a code for detecting an error must be added in addition to the data part of the communication data, and the transmission efficiency of the communication data is high. There was a problem that it decreased.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a data communication device capable of detecting an error and performing accurate communication without lowering the transmission efficiency of communication data. Especially.

[0005]

In order to achieve the above object, the invention according to claim 1 is a code discriminating means for discriminating at least two kinds of codes by a code length, the number of samplings per unit time is known. A means for calculating the total number of samplings from the data amount of the data, the code contained in the data, and the number of samplings per unit time when a certain amount of data is communicated, and the total number of receptions sampling at the time of reception Means and a comparing means for comparing the calculated total sampling number and the received total sampling number, and detecting an error from the result of the comparing means.

According to a second aspect of the present invention, in the data communication apparatus according to the first aspect, an error is detected when the calculated total sampling number and the received total sampling number do not match. is there.

According to a third aspect of the present invention, in the data communication apparatus according to the first aspect, an error is detected when the absolute value of the difference between the calculated total sampling number and the received total sampling number is a predetermined value or more. It is characterized by doing.

According to a fourth aspect of the present invention, in the data communication apparatus according to the third aspect, the predetermined value is determined according to the number of bits for which an error is desired to be detected.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an error detecting method for a data communication apparatus according to an embodiment of the present invention will be described with reference to FIGS.
I will explain based on this.

FIG. 1 is an example of application of the data communication apparatus of the present invention. Here, a data communication device using the human body 3 as a transmission path will be exemplified. FIG. 1 shows a state in which communication data is transmitted from the data transmission device 1 to the data reception device 2 using the human body 3 as a transmission path.

FIG. 2 shows a temporal shape of a signal transmitted as data. In the data communication device, it is necessary to give information to the signal 4 when performing data communication. Here,
The temporal shape of the signal 4 in the data transmitter 1 and the data receiver 2 in advance (hereinafter referred to as a code format)
Need to decide. The components of the code format according to the embodiment of the present invention consist of High and Low, and the information represented by the code format is "0" and "1". Here, FIG. 2A shows a code format of “0”, and FIG. 2B shows a code format of “1”. Here, when the unit time length is T, "0"
The length (time) of the code format of 1 is T, and the length (time) of the code format of "1" is 2T.

FIG. 3 is a block diagram of a data communication device, and a data transmission device and a data reception device constituting the data communication device,
The flow of the data communication signal between the blocks is shown.

Here, for example, when transmitting information "01", the data transmitter 11 generates a digital signal waveform based on the code format of FIG.
1, and transmits a signal (communication data) to the human body 31 via the transmission electrode 112 facing the human body. In the data receiving device 21, the communication data is received via the receiving electrode 211 that is in contact with the human body 31, and the received signal is demodulated by the demodulation unit 2.
The signal processing unit 21 obtains a digital signal waveform by demodulating at 12.
In "3", "01" is decoded from the digital signal waveform.

The error detection of the data communication apparatus of the present invention will be described below based on this case.

FIG. 4 shows the digital signal waveform input to the signal processing unit 213 of the data receiving device 21 and the signal processing unit 2.
13 shows sampling points when the signal is sampled. Here, “◯” in the digital signal waveform indicates a sampling point. Here, the sampling interval is T / 4, and the number of sampling times N per unit time length
Shows the case of 4.

FIG. 4A shows a digital signal waveform and a sampling point when "0" is received.
(B) shows a digital signal waveform and a sampling point when "1" is received. In the signal processing unit 213, the number of sampling times N per unit time length (here, N =
4), which counts the number of samplings during the falling edge. The sampling interval is T / N. Then, it is determined whether or not the received signal is in the code format based on the sampling number N counted during the falling edge, and it is also determined whether it is "0" or "1" in the case of the code format. That is, the data receiving device 21
Has a means for discriminating the code based on the code length.

Hereinafter, an embodiment of the present invention will be described, where the sampling interval is T / 4 and the sampling number N per unit time length is 4.

FIG. 5 shows the data amount B0 (the number of bits) of the data D in the communication data, the number of "1" in the data D, the total number of sampling times N1 in the data D, and the number of sampling times N per unit time length. It is a table showing the relationship of. From this table, there is a relation of the following equation between the data amount B0, the number of "1" s in the data D, the total number of times of sampling N1, and the number of times of sampling N per unit time length.

Formula 1: N1 = B0 × N + (the number of “1” in the data D) × N Here, when the data amount B0 and the sampling number N per unit time length are known, it is calculated from Formula 1. An error can be detected by comparing the total number of sampling times N1 in the received data D with the total number of sampling times N2 counted in the actually received data D.

In FIG. 6, reference numerals “0” and “1” are respectively assigned to 10
FIG. 6 is a diagram showing an example of variations in the number of sampling times N counted between the falling edges of signals in the signal processing unit 213 when transmitted 000 times. FIG. 6A shows a state in which ideal communication is performed, and there is no variation in the sampling number N counted between the falling edges of signals. When "0" is received, the sampling number N is 4, and when "1" is received, the sampling number N is 8. On the other hand, FIG. 6B shows that due to various factors such as the performance of the data receiving device 21, the influence of noise, and the decrease in communication volume.
Sampling count N that counts between falling edges of signals
This is the case when there is variation in. When such variations exist, measures are taken to relax the code determination conditions in the signal processing unit 213. For example, if the number of sampling times N counted between the falling edges of the signal is 3 to 5, it is determined to be "0", and if it is 7 to 9, it is determined to be "1". That is, when the communication is ideally performed, the code determination is performed by allowing one deviation from the sampling number N.

FIGS. 7 and 8 show the input waveform to the signal processing unit 213 and the pattern of the sampling points in the case of allowing one variation in the number of sampling times N to be counted between the falling edges of signals. It is a thing.
FIG. 7 shows a pattern when the data D is received as “0”. The number of sampling times N is 3 to 5, and there are 9 types of patterns. FIG. 8 shows a pattern when the data D is received as “1”. The number of sampling times N is 7
From 9 to 9, there are 21 types of patterns.

FIG. 9 shows an example of error detection in the data communication apparatus according to the first embodiment. It shows an example of error detection. This is an example in which error detection processing is performed for each 4-bit data, and “0001” is erroneously received even though “0000” is transmitted. The sampling number N between the falling edges of the first bit is 5 and the code is "0".
I have read. Next, the sampling number N between the trailing edges of the second bit is 3, and it is determined that the code "0" has been read. Thereafter, the sampling number N of the third bit is 4 and is determined to be a code "0", and the sampling number N of the fourth bit is 7 and is determined to be a code "1". In this way, the signal processing unit 213 determines that "0001" has been received.

Equation 1 is applied here. In the case shown in FIG. 9, the total sampling number N1 calculated from the received data “0001” is 20. On the other hand, the total number of sampling times N2 actually received from the 1st bit to the 4th bit is 19. The total number of sampling times N1 calculated by Equation 1 and the total number of sampling times N2 actually received
Since it is not the same value, it is judged that there was an error.

By comparing the number of times of sampling N1 and the total number of times of sampling N2 actually received in this way, it is possible to detect the error strictly.

FIG. 10 shows an example of error detection in the data communication apparatus according to the second embodiment. Although error detection processing is performed for each 4-bit data as in the first embodiment, in the present embodiment, a variation in two sampling times N is allowed for each 4-bit data. FIG. 10A shows an example in which “0100” is erroneously received even though “0000” is transmitted.
The sampling number N between the falling edges of the first bit is 3, and it is determined that the code “0” has been read. Next, the sampling number N between the trailing edges of the second bit is 7, and it is determined that the code "1" has been read. Thereafter, the sampling number N of the third bit is 3 and is determined to be a code "0", and the sampling number N of the fourth bit is 4 and is determined to be a code "0". In this way, the signal processing unit 213 outputs “010
It is determined that "0" has been received.

Equation 1 is applied here. In the case of the example shown in FIG. 10A, the total sampling number N1 calculated with the received data “0100” is 20. On the other hand, the total number of sampling times N2 actually received from the 1st bit to the 4th bit is 17. The absolute value M1 of the difference between the total number of sampling times N1 calculated by the equation 1 and the total number of sampling times N2 actually received is 3, and it is determined that there is an error.

Next, FIG. 10B shows an example in which "0000" is transmitted and "0000" is correctly received. 1
The number of sampling times N between the trailing edges of the bit is 3, and it is determined that the code “0” is read. Next, the sampling number N between the falling edges of the second bit is 4 and the code is "0".
I have read. Thereafter, the sampling number N of the third bit is 4 and is determined to be a code "0", and the sampling number N of the fourth bit is 4 and is determined to be a code "0".
In this way, the signal processing unit 213 determines that “0000” has been received.

Equation 1 is applied here. In the case of the example shown in FIG. 10B, the total sampling number N1 calculated with the received data “0000” is 16. On the other hand, the total number of sampling times N2 actually received from the 1st bit to the 4th bit is 15. The absolute value M1 of the difference between the total number of sampling times N1 calculated by the formula 1 and the total number of sampling times N2 actually received is 1, and it is determined that there is no error.

As described above, the total number of sampling times N1 calculated by the equation 1 and the total number of sampling times N actually received are
Since the absolute value M1 of the difference from 2 is greater than or equal to a constant M0 (here, 2), it is determined that there is an error.
There is an effect that an error can be detected accurately and efficiently while allowing a variation in the number of sampling times N in the entire data D.

FIG. 11 shows an example of error detection in the data communication apparatus according to the third embodiment, which allows five variations in the sampling number N for each 8-bit data. In FIG. 11A, although "00000000" is transmitted, "0000100" is erroneously transmitted.
This is an example of the case where is received. The number of sampling times N between the falling edges of the first bit is 4, and it is determined that the code “0” is read. Next, the number of sampling times N between the trailing edges of the second bit is 4, and it is determined that the code "0" is read. Thereafter, the sampling number N of the 3rd bit is 4 and it is determined that the code is "0".
Is judged as the code "0", and the number of samplings N of the 5th bit
Is 3 and the code is “0”, the sixth bit sampling number N is 7 and the code is “1”, the seventh bit sampling number N is 3 and the code is “0”, and the eighth bit sampling number N is 4 and is determined to be a code "0". In this way, the signal processing unit 213 determines that “00000100” has been received.

Equation 1 is applied here. In the case of the example shown in FIG. 11A, the received data “0000100”
The total number of sampling times N1 calculated in step 3 is 36. On the other hand, the total number of sampling times N2 actually received from the 1st bit to the 8th bit is 32. The absolute value M1 of the difference between the total number of sampling times N1 calculated by the equation 1 and the total number of sampling times N2 actually received is 4, and it is determined that there is no error. That is, this is an example in which a 1-bit error is not detected.

Next, FIG. 11B shows "00000000".
Erroneously sent "00000010"
This is an example when "0" is received. The sampling number N between the falling edges of the first bit is 3, and it is determined that the code “0” has been read. Next, the sampling number N between the trailing edges of the second bit is 7, and it is determined that the code "1" has been read. Thereafter, the sampling number N of the third bit is 3
Is judged as the code "0", and the number of samplings N of the 4th bit
Is 3 and the code is “0”, the fifth bit sampling number N is 3 and the code is “0”, the 6th bit sampling number N is 7 and the code is “1”, and the 7th bit sampling number N is 3 and is judged to be a code "0". The number of sampling times N of the 8th bit is 3 and is judged to be a code "0". In this way, the signal processing unit 213 outputs “01000100”.
Is judged to have been received.

Equation 1 is applied here. In the case of the example shown in FIG. 11B, the total sampling number N1 calculated with the received data “0000” is 40. On the other hand, the total number of sampling times N2 actually received from the 1st bit to the 8th bit is 32. The absolute value of the difference between the total number of sampling times N1 calculated by the equation 1 and the total number of sampling times N2 actually received is 8, and it is determined that there is an error. That is, a 2-bit error has been detected. Here, the number of error-detected bits B1 is determined by a constant M0 as the number of variations in the allowable number of times of sampling N.
It can be seen that

Thus, the data amount B0 of the data D,
Here, the number of error bits to be detected can be adjusted by adjusting the constant M0 as the number of variations in the allowable number of times of sampling N.

Although the embodiments of the present invention have been described above, the data communication apparatus using the human body 3 as a transmission path has been described as an example of the data communication apparatus, but the present invention is not limited to this.

[0036]

As described above, according to the first aspect of the present invention, the number of sampling times per unit time is known, the code discriminating means for discriminating at least two kinds of codes by the code length, and a fixed amount. Means for calculating the total number of times of sampling from the data amount of the data, the code contained in the data and the number of times of sampling per unit time, and means for obtaining the total number of times of sampling at the time of reception Since the comparison means for comparing the calculated total sampling number with the received total sampling number is provided and the error is detected from the result of the comparing means, the error can be made without lowering the transmission efficiency of the communication data. It has been possible to provide a data communication device capable of detecting an error and performing accurate communication.

In the invention described in claim 2, claim 1
In the data communication device described above, an error is detected when the calculated total sampling number and the received total sampling number do not match. Therefore, the variation in the sampling number in the entire data is strictly detected, and the error is detected. The effect of being able to detect is produced.

According to the invention of claim 3, claim 1
In the data communication device described above, an error is detected when the absolute value of the difference between the calculated total sampling number and the received total sampling number is equal to or greater than a predetermined value. This has the effect of being able to detect an error.

According to the invention of claim 4, claim 3
In the data communication device described above, since the predetermined value is determined according to the number of bits for which an error is desired to be detected, the detection level of the variation in the sampling number is adjusted to adjust the number of detected error bits. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a diagram showing an application example of an embodiment of the present invention.

FIG. 2 is a diagram showing a temporal shape of a communication code according to the embodiment of the present invention.

FIG. 3 is a block diagram showing an internal configuration of a communication device according to an embodiment of the present invention and a diagram showing a signal flow.

FIG. 4 is a diagram showing an input waveform and sampling points in a signal processing unit of the data receiving device.

FIG. 5 is a table showing the relationship among the data amount, the number of codes “1” in the data, the total number of sampling times in the data, and the sampling interval.

FIG. 6 is a diagram showing an example of variations in the number of sampling times between falling edges.

FIG. 7 is a diagram showing an input waveform and a pattern of sampling points.

FIG. 8 is a diagram showing an input waveform and a sampling point pattern.

FIG. 9 is a diagram showing an example of error detection in the data communication device according to the first embodiment of this invention.

FIG. 10 is a diagram showing an example of error detection in the data communication device according to the second embodiment of this invention.

FIG. 11 is a diagram showing an example of error detection in the data communication device according to the third embodiment of this invention.

[Explanation of symbols]

1 Data transmitter 2 Data receiving device 3 human body 11 Data transmitter (block diagram) 21 Data receiver (block diagram) 213 Signal processing unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masaru Hashimoto             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Masaki Koyama             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Yoshiko Suzuki             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F term (reference) 5K014 AA01 BA00 EA01 EA08

Claims (4)

[Claims] 1. A data amount of the data and the data when a certain amount of data is communicated with a code determining means that determines the number of samplings per unit time and determines at least two types of codes based on the code length. Means for calculating the total number of sampling times from the code included in and the number of sampling times per unit time, means for acquiring the total number of received sampling times at the time of reception, and comparing the calculated total number of sampling times with the total number of received sampling times A data communication device comprising a comparing means and detecting an error from a result of the comparing means. 2. The data communication device according to claim 1, wherein an error is detected when the calculated total sampling number and the received total sampling number do not match. 3. The data communication device according to claim 1, wherein an error is detected when an absolute value of a difference between the calculated total sampling number and the received total sampling number is equal to or larger than a predetermined value. 4. The data communication apparatus according to claim 3, wherein the predetermined value is determined according to the number of bits for which an error is desired to be detected.