JP2002111602A - Data communication device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data communication device which is capable of accurately making data communication even in an environment in which signals deteriorate in an S/N ratio. SOLUTION: A data communication device is equipped with a data transmitter 1 which carries out amplitude modulation on the basis of transmission data, and outputs signals from two transmission electrodes kept in contact with or located near a human body 3; and a receiving device 2 which receives signals outputted from the data transmitter 1 attached to the human body 3, demodulates the received signals, extracts an alternating component through an alternating component extracting part 11, and reads out a difference between a signal level of the alternating component and a predetermined reference value 70 through a signal reading part 12. The data receiving device 2 is equipped with a correlation determining part 13 which compares and determines a relative relation between the waveform of signals inputted to the signal reading part 12 and the reference value 70, and a correlation optimizing part which corrects a positional relation between the signal waveform and the reference value 70 to an optimal condition on the basis of the relative relation obtained through the correlation determining part 13.

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 the transmission and reception of data between a data transmitting device mounted on a human body and a data receiving device scheduled to come into contact with the human body. The present invention relates to a data communication device for performing.

[0002]

2. Description of the Related Art Conventionally, as a data communication method between a data transmitting device carried by a person and a data receiving device installed near the same, a method using wired communication by cable, a wireless communication using light, radio waves, or the like. Is used.

A case where data is transmitted from a data transmitting device to a data receiving device will be considered. In this case, in the method using wired communication, the device itself can be configured to be relatively inexpensive and small. However, before data transmission / reception is started, the data transmission device and the data reception device must be connected with a cable or the cable must be disconnected when data transmission / reception is completed, which is not always convenient for the user. There was a problem that it was not excellent. On the other hand, in the method using wireless communication, since the operation of connecting a cable is unnecessary, although data communication can be easily performed,
There has been a problem that the data communication device becomes expensive and large.

[0004] As means for solving such problems,
For example, Japanese Unexamined Patent Application Publication No.
-229357. In these devices, a data communication device that transmits data from a data transmission device attached to a human body to a data reception device using the human body as a transmission path has been proposed. It is possible to use a device that is inexpensive and small in size, and it is possible to easily transmit and receive data because there is no need to connect a cable or the like. here,
The data transmitted from the data transmission device has been modulated by the amplitude modulation method or the frequency modulation method in the data transmission device.

When the amplitude modulation method is used, it is necessary to distinguish whether the signal waveform is at a high level or a low level in order to finally identify data. The following are the measures.

FIG. 9 is a block diagram showing a part of the configuration of a data receiving apparatus 2 employing a method of amplitude-modulating an AC signal. As shown in FIG. 9, the transmission signal output from the data transmitting device 1 is received by the receiving electrode 65 as the signal 4 via the human body 3 and transmitted to the data receiving device 2. When the signal 4 is demodulated by the demodulation unit 10 including a filter (not shown) and an amplifier (not shown), the data receiving device 2 extracts an AC component from the signal demodulated by the demodulation unit 10. An AC component extraction unit 11; and a signal reading unit 12 that reads whether the signal level extracted by the AC component extraction unit 11 is at a HIGH level or a LOW level as compared with a predetermined reference value (so-called ground level). And a signal processing unit 17 for processing a signal read by the signal reading unit 12.

FIG. 10 is a waveform diagram showing signal processing in the data receiving device 2. FIG. 10A shows an original waveform of a transmission signal output from the data transmission device 1, FIG. 10B shows a signal waveform after the original waveform is demodulated by the demodulation unit 10, and FIG. Represents a signal waveform after the AC component is extracted by the AC component extracting unit 11. Thus, whether the signal waveform is at the HIGH level or the LOW level can be identified based on whether the signal level is higher or lower than the predetermined reference value 70. FIG. 10D shows that the signal is read by the signal reading unit 12 based on the reference value 70.
A digital waveform divided into an H level and a LOW level is shown, which restores the original waveform shown in FIG.

According to this method, since the signal level of the signal waveform automatically changes in response to the level change of the demodulated waveform, it is possible to effectively discriminate whether the signal waveform is at the HIGH level or the LOW level. Is possible.

FIG. 11 is a waveform diagram showing an example of a method in which information is provided according to a signal level.
It shows a measure for encoding with a combination of a GH level and a LOW level. Here, FIG.
FIG. 4 is an explanatory diagram showing that a bit string composed of a 2-bit LOW level and a 1-bit HIGH level is assigned to data “0”. FIG. 11B is an explanatory diagram showing that a bit string composed of a 1-bit LOW level and a 2-bit HIGH level is assigned to data “1”.

FIG. 12 shows a waveform diagram in which data “0” is continuously received by the data receiving device 2. FIG.
(A) shows the original waveform of the transmission signal output from the data transmission device 1, and (b) of FIG. 12 shows the signal waveform after the AC component is extracted by the AC component extraction unit 11.
However, when extracting the AC component, the H
The relative relationship between the signal level of the signal waveform and the reference value 70 varies according to the ratio between the IGH level and the LOW level. When data “0” is continuously input to the data receiving device 2,
In FIG. 12A, since the ratio of the LOW level is high, in FIG. 12B, the reference value 70 is lower (lower level side) than the center level of the signal waveform.

FIG. 13 shows a waveform diagram in which data "1" is continuously received by the data receiving device 2. FIG.
(A) shows the original waveform of the transmission signal output from the data transmission device 1, and (b) of FIG. 13 shows the signal waveform after the AC component is extracted by the AC component extraction unit 11.
Similar to the idea shown in the description of FIG. 12, when the AC component is extracted, if data “1” is continuously input to the data receiving device 2, the ratio of the HIGH level in FIG. 13 (b), the reference value 70 is higher (higher level side) than the center level of the signal waveform.

[0012]

However, in the data communication apparatus described above, the S / N ratio tends to fluctuate, and when the S / N ratio decreases, the transmission signal from the data transmission apparatus 1 is reduced. Has a problem that it is easily affected by noise when it is processed by the demodulation unit 10 or the like of the data receiving device 2.

FIG. 14 is a waveform diagram showing a case where noise or a high level drop portion is observed in the demodulated signal waveform. FIG. 14A shows an original waveform of a transmission signal output from the data transmission device 1. Ideally, the signal waveform shown in FIG. 10 has no noise or a drop in the HIGH level, but when the S / N ratio decreases, the signal waveform shown in FIG.
As shown in FIG. 4 (b), the noise B and HI
A dip A at the GH level can be seen.

Here, in the case where the ratio of the HIGH level in the original waveform of the transmission signal output from the data transmission device 1 is high, for the reason described in the explanation part of FIG.
As shown in FIG. 14C, the reference value 70 is shifted upward (to the HIGH level side) with respect to the center level of the signal waveform, and
The signal waveform due to the GH level dip A is shown in FIG.
There is a problem that the original waveform is not restored as shown in FIG.

In the case where the ratio of the LOW level is high in the original waveform of the transmission signal output from the data transmission device 1, the reason described in FIG.
As shown in FIG. 14E, the reference value 70 is biased downward (lower level side) with respect to the center level of the signal waveform, and the signal waveform is not restored to the original waveform by the noise part B as shown in FIG. There was a problem.

In particular, in a data communication apparatus using a human body as a transmission line, since the S / N ratio tends to fluctuate, the relative relationship between the reference value and the signal level of the signal waveform is determined by the data receiving apparatus 2. There has been a problem that signal processing is greatly affected.

The present invention has been made in view of the above problems, and its purpose is to change the S / N ratio.
It is an object of the present invention to provide a data communication device capable of accurately performing data communication even in an environment where the S / N ratio is reduced.

[0018]

The data communication device according to the first aspect includes two transmitting electrodes 20 and 30 that are in contact with or near the human body 3, an oscillating unit 40 that generates an AC signal, A modulator 50 for amplitude-modulating the AC signal based on the data to be transmitted, and a voltage corresponding to the modulated signal modulated by the modulator 50, the two transmission electrodes 20;
A data transmission device 1 having a voltage application unit 60 applied between the data transmission device 30 and a reception electrode 65 for receiving a modulation signal output from the data transmission device 1 when the human body 3 comes into contact with the data transmission device 1
A demodulation unit 10 for demodulating the modulated signal received via the reception electrode 65; an AC component extraction unit 11 for extracting an AC component from the signal demodulated by the demodulation unit 10; A data reading unit 12 for reading whether the signal level extracted in step 11 is higher or lower than a predetermined reference value 70, and a signal processing unit 17 for processing a signal read by the signal reading unit 12; A data communication apparatus comprising: a correlation determining unit configured to compare and determine a relative relationship between a signal waveform input to the signal reading unit and the reference value;
And a correlation optimizing unit that corrects the relative relationship between the level of the signal waveform and the reference value 70 to an optimal state based on the relative relationship obtained by the correlation determining unit 13. Is what you do.

Further, the data communication device according to claim 2 is
The invention according to claim 1, wherein the correlation optimizing unit is configured by a signal waveform attenuating unit 14 that attenuates a signal waveform obtained from the demodulating unit 10 at a predetermined cycle.

Further, the data communication device according to claim 3 is
The invention according to claim 1, wherein the correlation optimizing unit is configured by a signal level adjusting unit 15 that adjusts a reference level of a signal waveform after an AC component is extracted with respect to the reference value 70. Is what you do.

The data communication device according to claim 4 is
2. The invention according to claim 1, wherein the correlation optimizing unit includes a reference value adjusting unit 16 that adjusts a level of the reference value 70 with respect to a signal level of a signal waveform in the signal reading unit 12. Is what you do.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The premise of the present invention will be described below with reference to FIG.
Or, it will be described with reference to FIG.

FIG. 7 is a schematic diagram of a data communication apparatus using the human body 3 as a transmission path. The data transmission device 1 generates a transmission signal and transmits it to the human body 3, and a signal modulated based on data to be transmitted is applied to the human body 3. The transmission signal output from the data transmitting device 1 becomes a signal 4 via the human body 3 and is transmitted to the data receiving device 2.

As shown in FIG. 8A, a data transmission device 1 includes a reference potential electrode 2 disposed in contact with a human body.
0 and two transmitting electrodes 30, an oscillating unit 40 for generating an AC signal, a modulator 50 for amplitude-modulating the AC signal based on data to be transmitted, and a modulation signal modulated by the modulator 50. The corresponding voltage is applied to the two transmitting electrodes 20
And a voltage application section 60 applied between the voltage application section 30 and the voltage application section 30.

The data to be transmitted may be output from a microcomputer (not shown) or a ROM (not shown) provided in the data transmitting device 1, or the data transmitting device 1 may be provided with a sensor and transmit the detected sensor data. You may make it.

In FIG. 7, the data transmission device 1 is worn on the wrist, but the installation location is not particularly limited. Further, the reference potential electrode 20 and the transmission electrode 3
0 is sufficiently large, the reference potential electrode 2
0, since the transmission electrode 30 and the human body 3 are connected by electrostatic coupling even if they are apart from each other, the reference potential electrode 20 and the transmission electrode 30 are not in contact with each other if they are arranged near the human body 3. Is also good.

Also, in FIG. 7, the data receiving device 2 is located outside the human body 3, but the data transmitting device 1
In the same manner as described above, it may be mounted on the human body 3 and the installation place is not limited. Since the signal 4 passes through the human body 3, the signal 4 is a composite signal obtained by adding various noises to the modulation signal.

As shown in FIG. 8 (b), the data receiving device 2 includes a receiving electrode 65 for receiving the signal 4 output from the data transmitting device 1, and a demodulation unit 10 for demodulating the signal 4.

Hereinafter, a first embodiment of the present invention will be described with reference to FIG. 1 or FIG.

FIG. 1 is a block diagram showing a part of the configuration of the data receiving apparatus 2 according to the first embodiment of the present invention. In addition to the configuration of the data receiving apparatus 2 shown in FIG. A correlation determining unit 13 for comparing and determining a relative relationship between a signal waveform input to the reading unit 12 and a predetermined reference value 70 (so-called ground level) based on sampling data;
Signal waveform attenuator 14 for attenuating a signal waveform at a predetermined cycle
Is added. The correlation optimizing unit corrects the relative relationship between the signal waveform and the reference value 70 to an optimum state based on the relative relationship between the signal waveform obtained by the correlation determining unit 13 and the reference value 70. It is composed of a waveform attenuator 14.

The correlation judging unit 13 determines a certain assumed value for the number of HIGH-level samplings, and calculates H based on the assumed value.
If the number of samples at the IGH level is large, the reference value 70
Is determined to be below the optimum position (LOW level side), and if the number of HIGH level samples is smaller than the assumed value, the reference value 70 is higher than the optimum position (HIGH level).
(H level side).

Here, the optimum position means that the reference value 70 is
Between a HIGH level and a LOW level, a noise portion or H
It is particularly preferable that the reference value 70 is near the approximate center level of the signal waveform because it is located at a position where the influence of the drop portion of the IGH level does not appear. It is possible to make it less susceptible to the influence of the HIGH level drop portion.

The HIGH level of the waveform signal is forced to a LOW state by connecting a communication line (not shown) through which the signal flows to the ground. Signal waveform attenuator 14
Utilizes this principle, for example, by connecting a communication line and a ground at a predetermined cycle, and thereby
By adjusting the ratio between the GH level and the LOW level, the relative relationship between the signal level of the signal waveform and the reference value 70 can be optimized.

As shown in FIG. 14E, when the reference value 70 is located below the optimum position (low level side) and is easily affected by the noise portion B, the communication line and the ground are grounded. When the time is shortened, the ratio of the HIGH level of the signal waveform increases, and the reference value 70 increases.
With reference to 0, the signal level of the signal waveform relatively decreases.

Further, as shown in FIG.
However, if the signal level of the signal waveform is located above the optimum position (higher level side) and is more susceptible to the high-level dip A, a longer time is required to ground the communication line and the ground. Since the ratio of the HIGH level of the signal waveform decreases and the reference value 70 decreases, the reference value 7
With reference to 0, the signal level of the signal waveform relatively increases.

FIG. 2 is a waveform diagram before and after the input to the signal waveform attenuator 14. FIG. 2A shows that the reference value 70 is
This is an example of a case where the signal waveform is located above the center level of the signal waveform (higher level side). FIG. 2B is a diagram in which the time for connecting the communication line and the ground is a predetermined period T synchronized with the data sampling period and the signal waveform is controlled, and immediately after the connection to the ground is terminated (FIG. By reading the data in the arrow C) of 2 (b), it is possible to restore the original waveform of the transmission signal output from the data transmission device 1. As shown in FIG. 2B, the signal level of the signal waveform after the input to the signal waveform attenuator 14 is higher than that before the input to the signal waveform attenuator 14.

Next, a second embodiment of the present invention will be described with reference to FIG. 3 or FIG.

FIG. 3 is a block diagram showing a part of the configuration of the data receiving apparatus 2 according to the second embodiment of the present invention. In addition to the configuration of the receiving apparatus 2 shown in FIG. 9, the signal waveform input to the signal reading unit 12 and a predetermined reference value 70
(A so-called ground level) and a signal level adjuster 15 for adjusting the reference level of the signal waveform after the AC component is extracted with respect to the reference value 70. Things. The correlation optimizing unit corrects the relative relationship between the signal waveform and the reference value 70 to an optimum state based on the relative relationship between the signal waveform obtained by the correlation determining unit 13 and the reference value 70. It is composed of a level adjusting unit 15.

The signal level adjuster 15 adjusts the signal level of the signal waveform after the AC component is extracted so that the signal level is at the optimum position shown in the first embodiment with respect to the reference value 70. Signal level of signal waveform and reference value 70
Can be optimized. That is, the signal level adjusting unit 15 has a function of relatively adjusting the signal level of the signal waveform to a position where the center level of the signal waveform and the reference value 70 are substantially the same with respect to the reference value 70. It becomes.

Hereinafter, the signal level of the signal waveform and the reference value 7
FIG. 4 shows an example of an operation for optimizing the relative relationship with 0.
It is shown using.

FIG. 4 is a waveform diagram before and after the input to the signal level adjusting unit 15. FIG. 4A shows a case where the reference value 70 is higher than the center level of the signal waveform. At this time, the signal level adjusting unit 15 relatively sets the signal level of the signal waveform relative to the reference value 70 so that the center level of the signal waveform and the reference value 70 are substantially the same as shown in FIG. Adjust to raise to the level position.

Next, a third embodiment of the present invention will be described with reference to FIG. 5 or FIG.

FIG. 5 is a block diagram showing a part of the configuration of the data receiving apparatus 2 according to the third embodiment of the present invention.

Here, the second embodiment of the present invention is characterized in that the signal level of the signal waveform is adjusted with respect to the reference value 70. However, the third embodiment maintains the signal level of the signal waveform as it is. Thus, the level of the reference value 70 is adjusted.

In addition to the configuration of the receiving apparatus 2 shown in FIG. 9, a correlation judging section 13 for comparing and judging a relative relationship between a signal waveform inputted to the signal reading section 12 and a predetermined reference value 70 (so-called ground level). And a reference value adjustment unit 16 that adjusts the level of the reference value 70 to the reference value 80 with respect to the signal level of the signal waveform in the signal reading unit 12. Here, the correlation optimizing unit, based on the relative relationship between the signal waveform obtained by the correlation determining unit 13 and the reference value 70, adjusts the relative relationship between the level of the signal waveform and the reference value 70 to an optimal state. It is composed of a value adjusting unit 16.

The reference value adjusting section 16 adjusts the reference value 70 to the optimum position shown in the first embodiment in accordance with the signal level of the signal waveform, thereby adjusting the signal level of the signal waveform. The relative relationship with the later reference value 80 can be optimized. That is, the reference value adjustment unit 16
With reference to the signal level of the signal waveform, the reference value is relatively 7
It has a function of adjusting 0 to a position (reference value 80) where the center level of the signal waveform and the reference value 70 are substantially the same level.

Hereinafter, the signal level of the signal waveform and the reference value 7
An example of the operation for optimizing the relative relationship with 0 is shown in FIG.
It is shown using.

FIG. 6 is a waveform diagram before and after the input to the reference value adjusting unit 16. FIG. 6A shows a case where the reference value 70 is higher than the center level of the signal waveform. At this time, the reference value adjusting unit 16 relatively sets the reference value 70 on the basis of the signal level of the signal waveform, and as shown in FIG. 6B, the center level of the signal waveform and the reference value 70 are substantially the same. Adjustment is made to lower to the level position (reference value 80).

It should be noted that the present invention is not limited to the data communication device of the above-described embodiment, and various modifications are possible within the scope of the claims. All of these are included.

[0050]

As described above, in the data communication apparatus according to the first aspect of the present invention, the data receiving apparatus performs the relative relationship between the signal waveform input to the signal reading unit and the predetermined reference value. And a correlation optimizing unit that corrects the relative relationship between the level of the signal waveform and the reference value to an optimal state based on the relative relationship obtained by the correlation determining unit. It is possible to optimize the relative relationship between the signal level of the signal waveform and the reference value,
There is an effect that it is possible to provide a data communication device that can accurately communicate even in an environment where the S / N ratio fluctuates and the S / N ratio is reduced.

According to a second aspect of the present invention, in the data communication apparatus, the correlation optimizing section is constituted by a signal waveform attenuating section, and the time for connecting the communication line through which the signal flows to the ground is set to a predetermined period. By controlling the signal waveform in such a manner, the ratio between the HIGH level and the LOW level of the signal waveform is adjusted, and the effect is achieved that the relative relationship between the signal level of the signal waveform and the reference value can be optimized.

According to a third aspect of the present invention, in the data communication apparatus, the correlation optimizing unit is constituted by a signal level adjusting unit, and the signal level of the signal waveform after the AC component is extracted is set as a reference value. By adjusting the position of the signal waveform to the optimum position, it is possible to optimize the relative relationship between the signal level of the signal waveform and the reference value.

In the data communication apparatus according to the present invention, the correlation optimizing unit is constituted by a reference value adjusting unit, so that the reference value comes to an optimum position in accordance with the signal level of the signal waveform. The adjustment has an effect that the relative relationship between the signal level of the signal waveform and the reference value can be optimized.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a data receiving device according to a first embodiment of the present invention.

FIG. 2 is a waveform diagram before and after input of a signal waveform attenuator according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a configuration of a data receiving device according to a second embodiment of the present invention.

FIG. 4 is a waveform diagram before and after an input of a signal level adjusting unit according to a second embodiment of the present invention.

FIG. 5 is a block diagram illustrating a configuration of a data receiving device according to a third embodiment of the present invention.

FIG. 6 is a waveform diagram before and after an input of a reference value adjusting unit according to a third embodiment of the present invention.

FIG. 7 is a schematic diagram of a data communication device according to a conventional example.

FIG. 8 is a block diagram illustrating a configuration of a data communication device according to a conventional example.

FIG. 9 is a block diagram illustrating a configuration of a data receiving device according to a conventional example.

FIG. 10 is a waveform diagram showing signal processing in a data receiving device according to a conventional example.

FIG. 11 is an explanatory diagram showing data “0” and data “1” according to a conventional example.

FIG. 12 is a waveform diagram of data “0” according to a conventional example continuously received by a data receiving apparatus.

FIG. 13 is a waveform chart of data “1” according to a conventional example continuously received by a data receiving apparatus.

FIG. 14 is a waveform chart according to a conventional example when a relative relationship between a signal waveform and a reference value is not optimal.

[Explanation of symbols]

 Reference Signs List 1 data transmission device 2 data reception device 3 human body 4 signal 10 demodulation unit 11 AC component extraction unit 12 signal reading unit 13 correlation determination unit 14 signal waveform attenuation unit (correlation optimal unit) 15 signal level adjustment unit (correlation optimal unit) 16 reference Value adjustment unit (correlation optimum unit) 17 Signal processing unit 20 Reference potential electrode (transmission electrode) 30 Transmission electrode (transmission electrode) 40 Transmission unit 50 Modulation unit 60 Voltage application unit 65 Receiving electrode 70 Reference value 80 Reference value

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaru Hashimoto 1048, Kazuma Kadoma, Kadoma, Osaka Prefecture Inside the Matsushita Electric Works, Ltd. 72) Inventor Yoshiko Suzuki 1048 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Works, Ltd. 5K012 AB04 AB08 AB19 AC09 AC11 AD05 5K029 AA02 AA04 CC01 CC04

Claims (4)

[Claims] 1. An oscillator for generating an AC signal, an oscillator for generating an AC signal, a modulator for amplitude-modulating the AC signal based on data to be transmitted, and the modulator. A data transmission device comprising a voltage application unit for applying a voltage corresponding to a modulation signal modulated by the method between the two transmission electrodes, and receiving a modulation signal output from the data transmission device when a human body comes into contact with the data transmission device. A receiving electrode, a demodulating unit for demodulating the modulated signal received via the receiving electrode, an ac component extracting unit for extracting an ac component of the signal demodulated by the demodulating unit, and extracting by the ac component extracting unit A signal reading unit that reads whether the read signal level is higher or lower than a predetermined reference value, and a data receiving device that includes a signal processing unit that processes a signal read by the signal reading unit. In the data communication device, the data receiving device, a correlation determining unit for comparing and determining the relative relationship between the signal waveform input to the signal reading unit and the reference value, and the relative relationship obtained by the correlation determining unit And a correlation optimizing unit for correcting a relative relationship between levels of the signal waveform and the reference value to an optimum state. 2. The data communication device according to claim 1, wherein the correlation optimizing unit is configured by a signal waveform attenuating unit that attenuates a signal waveform obtained from the demodulating unit at a predetermined cycle. 3. The signal processing apparatus according to claim 1, wherein the correlation optimizing unit includes a signal level adjusting unit that adjusts a reference level of the signal waveform after the AC component is extracted with respect to the reference value. Data communication equipment. 4. The correlation optimization unit according to claim 1, wherein the correlation optimization unit includes a reference value adjustment unit that adjusts the level of the reference value with respect to the signal level of the signal waveform in the signal reading unit. Data communication device.