JP2007201835A - Communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication apparatus capable of preventing erroneous recognition of a noise as a confirming signal or an activation signal. <P>SOLUTION: A communication device in a data receiving side has a signal transmission means for transmitting the activation signal for causing an opposite communication device to start data transmission, and the confirming signal for notifying the opposite communication device that the data have been received, to the opposite communication device. A communication device in a data transmitting side has a signal processing means for sampling the activation signal and the confirming signal at a predetermined period and identifying them. Of three kinds of transmission codes "0", "1", and "S" each having a wavelength of a shape obtained by one reversion of a binary value and having different lengths of a time axis direction, the signal transmission means arranges two transmission codes "S" having the longest length in time axis direction, and then, adds a combination of two or more transmission codes having longer in the time axis direction than one transmission code "1" having the second largest length of the time axis direction, thereby generating each of the activation signal and the confirming signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a communication apparatus including a pair of communication devices that perform data communication through a transmission path.

  2. Description of the Related Art Conventionally, as this type of communication apparatus, a device that converts target data into a plurality of data packets and sequentially transmits the plurality of data packets from the communication device to the communication device is known.

  Some data packets are composed of three types of transmission codes each having a waveform in which binary values are inverted once and having different lengths in the time axis direction. Specifically, a data portion is formed from an array of two types of transmission codes “0, 1”, and another transmission code “S” is added to each of the front and rear of the data portion (see FIG. 3). ). In these three types of transmission codes, the length in the time axis direction of “0” is set to T, the length in the time axis direction of “1” is set to 2T, and the length in the time axis direction of “S” is set to 3T. (See FIG. 2).

  By the way, in the communication apparatus as described above, the communication device on the data receiving side has a function of returning a confirmation signal (ACK signal) notifying that the data has been normally received to the other communication device. Is known (see, for example, Patent Document 1). Further, there is a communication device having a function of transmitting an activation signal for each communication device to activate the communication device on the other side. In this communication apparatus, data communication can be started by transmitting an activation signal to the communication apparatus on the other side.

  In the confirmation signal and the activation signal, an arrangement of transmission codes “SS” that is not used for the data packet is often adopted so as to be distinguished from the data packet. Further, in order to distinguish between the confirmation signal and the activation signal, the confirmation signal adopts the format “SS0” in which the transmission code “0” is added after “SS” as shown in FIG. As shown in FIG. 8B, the signal employs the format “SS1” in which the transmission code “1” is added after “SS”.

Then, the communication device samples the received data packet, the start signal, and the confirmation signal at a constant period upon reception of the data packet, the start signal, and the confirmation signal, determines the binary value for each sampling, and arranges the transmission code array. Identify. Therefore, the longer the length of the signal in the time axis direction, the greater the number of sampling times, so it can be easily distinguished from noise, and conversely, the shorter the length of the signal in the time axis direction, the smaller the number of sampling times. Difficult to distinguish.
JP-A-6-233353 (page 3)

  However, in the above-described conventional example, the length of the confirmation signal and the activation signal in the time axis direction is relatively short (7T for the confirmation signal and 8T for the activation signal). There is a high possibility that the machine erroneously recognizes the noise as a confirmation signal or activation signal. That is, noise countermeasures may be insufficient depending on the environment of the communication device.

  The present invention has been made in view of the above-described reasons, and an object thereof is to provide a communication device that is less likely to misrecognize noise as a confirmation signal or an activation signal.

  According to the first aspect of the present invention, the communication device having a pair of communication devices that perform data communication through the transmission path, the communication device on the data receiving side sends an activation signal and data for starting transmission of data to the other communication device. Signal processing means for transmitting a confirmation signal notifying that the signal has been received to the communication device on the other side, and the communication device on the data transmission side identifies and identifies the start signal and the confirmation signal by sampling at a constant cycle The signal transmission means has a waveform obtained by inverting the binary value once and has the longest length in the time axis direction among three types of transmission codes having different lengths in the time axis direction. After arranging two codes, a start signal and a confirmation signal are added by adding a combination of two or more transmission codes that are longer in the time axis direction than one transmission code having the second longest length in the time axis direction. Generating each of And wherein the door.

  According to this configuration, the signal transmission unit arranges two transmission codes having the longest length in the time axis direction among the three types of transmission codes, and then the transmission code having the second length in the time axis direction. Since each of the start signal and the confirmation signal is generated by adding a combination of two or more transmission codes that are longer in the time axis direction than one of the above, the time of the start signal and the confirmation signal is compared with the conventional example. Each axial length becomes longer. Therefore, when noise is mixed in from a transmission line or the like, it becomes difficult for the communication device to erroneously recognize the noise as an activation signal or a confirmation signal.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the signal transmitting means generates each of the activation signal and the confirmation signal by combining all types of the transmission codes.

  If the start signal and the confirmation signal are each composed of only two types of transmission codes, the communication device may be in an environment where it repeatedly receives noise having the same length in the time axis direction as one of the two types of transmission codes. For example, when noise having the same length in the time axis direction as the other transmission code of the two types is received, there is a possibility that these noises may be erroneously recognized as an activation signal or a confirmation signal. On the other hand, according to the configuration of claim 2, since the start signal and the confirmation signal are each composed of a combination of all three types of transmission codes, the communication device can use one of the three types of transmission codes and the time axis direction. Even if it is in an environment that repeatedly receives the same noise and the same length in the time axis direction as another type of transmission code, these noises are misrecognized as startup signals or confirmation signals There is no.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the signal transmitting means has a waveform in which a binary value is inverted once, and the length in the time axis direction is the length of the transmission code. Create a special code that is longer in the time axis direction than the longest transmission code, and use the special code as a transmission code to be added after arranging two transmission codes having the longest length in the time axis direction among the transmission codes Each of the activation signal and the confirmation signal is generated.

  If the difference in length in the time axis direction among the three types of transmission codes constituting the activation signal and the confirmation signal is relatively small, the communication device has a length of 2 in the time axis direction among the three types of transmission codes. When the second long transmission code and the time-axis length are repeatedly subject to the same noise, this noise may be mistakenly recognized as the longest transmission code or the shortest transmission code. There is a possibility that noise may be erroneously recognized as a start signal or a confirmation signal. On the other hand, according to the configuration of claim 3, the activation signal and the confirmation signal are configured using a special code that is longer in the time axis direction than the transmission code having the longest length in the time axis direction among the transmission codes. Even if the communication device is in an environment where it repeatedly receives noise with the same length in the time axis direction as the transmission code having the second length in the time axis direction among the three types of transmission codes, this noise is special. The signal is not erroneously recognized as a signal, so that noise is not erroneously recognized as a start signal or a confirmation signal.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, each of the communication devices has a bipolar electrode, and at least one of the electrodes in each of the communication devices has a different part of the human body. The transmission line is formed in a portion that is in contact with each other and exists between human bodies.

  According to this configuration, in spite of the configuration in which noise is likely to be mixed in from the transmission path that includes a part of the human body in the transmission path, the communication device is configured as described above according to any one of claims 1 to 3. There is an advantage that noise is not easily recognized as a start signal or a confirmation signal.

  In the present invention, after the signal transmitting means arranges two transmission codes having the longest length in the time axis direction among the three types of transmission codes, the transmission code 1 is the second longest transmission code in the time axis direction. Since each of the start signal and the confirmation signal is generated by adding a combination of two or more transmission codes that are longer in the time axis direction than the corresponding one, the time axis direction of the start signal and the confirmation signal compared to the conventional example The length of each increases. Therefore, there is an advantage that when noise is mixed in from a transmission line or the like, the communication device does not easily recognize the noise as an activation signal or a confirmation signal.

  The communication apparatus of this embodiment includes two communication devices A and B that perform data communication through a transmission path.

  Between the communication device A and the communication device B, the target data is a plurality of data composed of an array of three kinds of transmission codes “0”, “1”, and “S” as shown in FIG. Convert to packet and transmit. Each data packet has a data portion composed of a combination of transmission code “0” and transmission code “1” as shown in FIG. 3, and transmission code “S” is added before and after this data portion, respectively. Thus, the communication signal is configured in the format of “S... (Data)... S”. The transmission code is an electric signal having a waveform obtained by inverting the binary values of H level and L level once, and the length in the time axis direction is different for each type. As shown in FIG. 2, the above three types of transmission codes have a time-axis length of “0” T, a time-axis length of “1” of 2T, and a length of “S” in the time-axis direction. Is set to 3T.

  By the way, in this embodiment, what is used for what is called human body communication which performs near field communication using a part of human body for the transmission path between the communication apparatus A and the communication apparatus B is illustrated as a communication apparatus.

  Specifically, as shown in FIG. 4, in the communication apparatus of the present embodiment, one communication device A is attached to the arm of a human body H, and the other communication device B is installed at a predetermined position. The communication device A attached to the arm of the human body H is configured, for example, as a wristwatch.

  Each communication device A and B has two electrodes, respectively, between the first electrode P1a of the communication device A and the first electrode P1b of the communication device B, and the second electrode P2a of the communication device A. By forming an electrical path between each of the communication devices B and the second electrode P2b of the communication device B, a transmission path is formed between the communication devices A and B. In the communication device A, two electrodes P1a and P2a are provided in contact with the human body H along the longitudinal direction of the arm. The electrode provided on the fingertip side is the first electrode P1a, and the electrode provided on the shoulder side is the second electrode P2a.

  In this communication apparatus, a person wearing the communication device A stands at a position facing the second electrode P2b of the communication device B and touches the first electrode P1b of the communication device B with the fingertip of the arm wearing the communication device A. By touching, a transmission path is formed between the communication device A and the communication device B, and data communication between the communication devices A and B becomes possible. That is, the first electrodes P1a and P1b of both communication devices A and B are electrically connected to each other by the portion from the first electrode P1a of the communication device A in the human body H to the fingertip, and the first of the communication devices A in the human body H is connected. The second electrodes P2a and P2b of the two communication devices A and B are electrically connected to each other by the electrostatic coupling between the second electrode P2a and the foot of the second electrode P2a and the second electrode P2b of the communication device B. Will be. The communication apparatus of this embodiment can transmit a communication signal bidirectionally between the pair of communication devices A and B by passing through the transmission path formed in this way.

  Below, the structure of each communication apparatus A and B is demonstrated.

  As shown in FIG. 5A, the communication device A includes a transmission unit 1 that transmits a communication signal, a reception unit 2 that receives a communication signal, and a microcomputer (microcomputer) connected to the transmission unit 1 and the reception unit 2. ) 3 and a storage unit 5 and a battery 13 connected to the microcomputer. The transmission unit 1 generates an alternating current signal, modulates the alternating current signal based on a communication signal to be transmitted into a modulated signal, and applies a voltage corresponding to the modulated signal between the bipolar electrodes P1a and P2a. To transmit a communication signal. The receiving unit 2 receives the communication signal by detecting the voltage between the bipolar electrodes P1a and P2a, demodulating the received modulation signal, and extracting the communication signal. The microcomputer 3 includes a signal processing unit (signal processing means) 6 for processing the received communication signal, a receiving unit power control unit 7 for turning on / off the power of the receiving unit 2, and a transmitting unit power control for turning on / off the power of the transmitting unit 1. Unit 8 and a signal processing unit control unit 9 that controls the timing of operating the signal processing unit 6. The signal processing unit 6 includes a sampling unit 10 that samples a received communication signal at a constant period, a code determination unit 11 that determines an H level and an L level for each sampling, and an array of transmission codes to determine a data packet. And a communication packet determination unit 12 to be obtained.

  On the other hand, as shown in FIG. 5B, the communication device B includes a transmission unit 1, a reception unit 2, a microcomputer 3, and a storage unit 5 like the communication device A. However, in the communication device B, a power supply unit 13 ′ that receives power supply from a commercial power supply is provided instead of the battery 13. Further, the communication device B has an interface 14 for connecting another processing device, and is configured to be capable of data communication with another processing device.

  The communication device configured as described above operates such that, for example, information stored in the storage unit 5 of the communication device A on the human body side is read by the communication device B and collated with information in the storage unit 5 of the communication device B. It is used for ID authentication at the time of entering and leaving the facility. That is, if the communication device A is attached to the human body, ID authentication can be performed without using a magnetic card or IC card as in the conventional case. In addition, the above communication device can be used in a system for monitoring the health state of the human body. In this case, a sensor for detecting the health state of the human body (such as a pulse) is provided in the communication device A to control the state of the human body. The communication device A is temporarily stored in the storage unit 5, and the information in the storage unit 5 of the communication device A is periodically read out by the communication device B, so that the communication device A can be connected to the communication device B or another processing device connected to the communication device B. Monitor the health of the human body.

  Each of the communication devices A and B receives an activation signal for starting data communication with respect to the communication devices A and B on the other side, and a confirmation signal (ACK signal) for notifying that data has been received. Each of A and B has signal transmission means (not shown) for transmitting as a communication signal. The activation signal and the confirmation signal are communication signals that are shorter in the time axis direction than the data packet to be transmitted. Further, when each communication device A, B receives a confirmation signal from the other communication device A, B when transmitting the data packet, the transmission of the data packet to the other communication device A, B becomes normal without transmission error. Each of them has a function to determine that it has been done. In short, the communication devices A and B on the data packet transmitting side receive the activation signal from the communication devices A and B on the other side and start transmitting the data packet, and after transmitting the data packet, When the confirmation signals from A and B are received, it is determined that the data packet is normally transmitted. On the other hand, when the confirmation signals from the other communication devices A and B are not received, the data packet Is not transmitted normally.

  Here, as a configuration for starting each communication device A, B, one communication device A, B always transmits a start signal, and when a transmission path is formed between both communication devices A, B, data is automatically generated. In this embodiment, since the battery is used as a power source in the communication device A attached to the human body, the communication device B is configured to reduce the standby power of the communication device A. An activation switch (not shown) for activation is provided in the communication device B, and an activation signal is transmitted from the communication device B to the communication device A when the activation switch is pressed. In this configuration, standby power of the communication device B is also reduced, leading to power saving of the communication device. As the activation switch, a tact switch or a touch sensor incorporated in the base of the electrode P1b may be used so that the activation switch is turned on when the human body touches the first electrode P1b of the communication device B.

  Regarding the confirmation signal and the activation signal, the basic configuration is the same as that described as the conventional example. That is, in the confirmation signal and the activation signal, an arrangement of a transmission code “SS” that is not used for the data packet is employed in order to distinguish it from the data packet. Further, in order to distinguish between the confirmation signal and the activation signal, the confirmation signal adopts the format “SS0” in which the transmission code “0” is added after “SS” as shown in FIG. As shown in FIG. 8B, the signal employs the format “SS1” in which the transmission code “1” is added after “SS”. Then, the communication devices A and B on the data transmitting side sample the received communication signal at a constant cycle by the signal processing unit 6 and discriminate between the H level and the L level for each sampling, thereby transmitting the transmission code. The confirmation signal and the activation signal are identified by discriminating the arrangement.

  By the way, in the communication apparatus used for human body communication like this embodiment, noise is likely to be mixed from the transmission path (a part of the human body) compared to the communication apparatus using the metal conductor as the transmission path. In B, there is a high possibility that noise mixed in from the transmission path is erroneously recognized as a start signal or a confirmation signal. Therefore, in this embodiment, the startup signal and the confirmation signal are configured as described below to prevent noise from being erroneously recognized as the startup signal and the confirmation signal.

That is, since each transmission code constituting the activation signal and the confirmation signal is represented by binary values (H level and L level), the signal processing unit 6 has the same noise as the activation signal and confirmation signal for one sampling. Probability is halved. In addition, when sampling is performed a plurality of times within the period in which the signal processing unit 6 receives the activation signal and the confirmation signal, the noise is the activation signal and the confirmation only after the noise matches the activation signal and the confirmation signal in all the sampling results. It will be misrecognized as a signal. Therefore, assuming that each communication device A and B receives noise having a random waveform in a state in which no signal is transmitted from both communication devices A and B, the signal processing unit 6 has time T. When sampling is performed n times during this period (that is, when sampling is performed at a period of T / n), the probability that a noise is erroneously recognized as a transmission code “0” having a length T in the time axis direction is 1 / (2 ⁿ ) Similarly, the probability that a noise is erroneously recognized as a signal of length mT is 1 / (2 ^mn ). Therefore, the probability that noise is erroneously recognized as a transmission code “1” having a length of 2T is 1 / (2 ²ⁿ ), and the probability that noise is erroneously recognized as transmission code “S” having a length of 3T is 1 / (2 ³ⁿ ). In this way, the longer the signal in the time axis direction, the smaller the probability that noise is erroneously recognized as this signal in the communication device.

Therefore, in the communication apparatus according to the present embodiment, the signal transmission unit combines the transmission code so that the length of each of the activation signal and the confirmation signal in the time axis direction is longer than that of the conventional example. Each is generated. Specifically, for the confirmation signal, the transmission code “1” is added to the above-mentioned “SS0” signal, and the length in the time axis direction represented by “SS01” as shown in FIG. Is a 9T signal, and for the activation signal, the transmission code “0” is added to the above-mentioned “SS1” signal, and the length in the time axis direction represented by “SS10” as shown in FIG. Is a 9T signal. Thereby, in the communication devices A and B, when sampling is performed at a period of T / n, the probability of erroneously recognizing noise as an activation signal or a confirmation signal is 1 / ( ²⁹ⁿ ). Here, in the present embodiment, the length T in the time axis direction is 360 μs, and the sampling period is 180 μs. That is, since T / n = 360 / n = 180 becomes n = 2, the probability that the noise is erroneously recognized as the activation signal or the confirmation signal is 1/262144, and the noise is erroneously recognized as the activation signal or the confirmation signal. There is hardly anything.

  Here, since the activation signal and the confirmation signal have the same length (9T) in the time axis direction, the probability that the noise is erroneously recognized as the activation signal and the probability that the noise is erroneously recognized as the confirmation signal are the same. Thus, the activation signal and the confirmation signal have the same noise resistance.

  In addition, in order to make each of the activation signal and the confirmation signal longer in the time axis direction than in the conventional example, the signal transmission unit transmits the transmission code “S having the longest length in the time axis direction among the three types of transmission codes. ”Are arranged, then a combination of two or more transmission codes that are longer in the time axis direction than one transmission code“ 1 ”having the second longest length in the time axis direction is added to the start signal Since the activation signal is not limited to “SS10” and the confirmation signal is “SS01” as described above, for example, the activation signal or the confirmation signal is “SSSSS00000”. It is good.

  However, if the activation signal or the confirmation signal is composed of only two types of transmission codes “0” and “S” in this way, the communication devices A and B can transmit one of the two types of transmission codes and If you are in an environment that repeatedly receives noise of the same length in the time axis direction, when you receive noise of the same length in the time axis direction as the other transmission code of the two types, these noises are There is a possibility of erroneous recognition as a confirmation signal. That is, as shown in FIG. 6, the communication devices A and B receive this noise “000... 000” in an environment that repeatedly receives noise having the same length (T) as the transmission code “0” in the time axis direction. Will be misrecognized as a signal. In such an environment, when the communication devices A and B continuously receive the noise having the same length (3T) in the time axis direction as the transmission code “S”, the communication devices A and B There is a possibility that noise is erroneously recognized as the signal “SSSSS00000”. Accordingly, it is desirable that each of the confirmation signal and the activation signal includes all three types of transmission codes (0, 1, S) such as “SS01” and “SS10” described above.

  As described above, when the activation signal and the confirmation signal each include three types of transmission codes, the communication devices A and B can transmit one type of transmission code among the three types of transmission codes included in the activation signal and the confirmation signal. Even in an environment where the noise corresponding to the code is repeatedly received, the noise and the activation signal or the confirmation signal can be distinguished by the remaining two types of transmission codes. Therefore, the communication devices A and B are in an environment that repeatedly receives noise corresponding to one type of transmission code among the three types of transmission codes, and may receive noise corresponding to one type of transmission code. However, there is an advantage that the noise and the confirmation signal or the activation signal can be distinguished from each other by the remaining one type of transmission code, and it is difficult to erroneously recognize the noise as the confirmation signal or the activation signal. In short, noise resistance in the communication device is improved.

  Furthermore, the signal transmission means is a special code that is longer in the time axis direction (here, the length is 30T) than the transmission code “S” that is the longest in the time axis direction (here, the length is 3T) among the three types of transmission codes described above. “N” may be created, and each of the activation signal and the confirmation signal may be generated using this special code as a transmission code. That is, for example, the confirmation signal is a signal having a length 37T in the time axis direction represented by “SS0N” as shown in FIG.

  If the transmission code “1” is used instead of the transmission code “N”, all the transmission codes (0, 1, S) constituting the confirmation signal and the activation signal are close in length in the time axis direction. Thus, for example, when the communication devices A and B repeatedly receive noise having the same length (2T) in the time axis direction as the transmission code “1”, the communication devices A and B not only erroneously recognize this noise as the transmission code “1”. In some cases, the transmission code “0” or the transmission code “S” having a short length in the time axis direction may be erroneously recognized, and thus noise may be erroneously recognized as a start signal or a confirmation signal. On the other hand, in the configuration including the special code “N” in the confirmation signal and the start signal as described above, even if the communication devices A and B have the same length (2T) noise in the time axis direction as the transmission code “1”. This noise is not only erroneously recognized as the transmission code “1”, but may be erroneously recognized as the transmission code “0” or the transmission code “S” whose length in the time axis direction is close. Is not erroneously recognized as noise as a special code “N” having a significantly different length in the time axis direction, and as a result, there is an advantage that noise is not erroneously recognized as an activation signal or a confirmation signal. In short, noise resistance in the communication device is further improved.

  In the above embodiment, the communication device in which one communication device A is mounted on the arm of the human body H and the other communication device B is installed at a predetermined position is illustrated, but the communication device B is not limited to this configuration. Like the communication device A, it is configured to be mounted on the arm of the human body H, both the communication devices A and B are mounted on the arms of the other human body H, and the human who wears the communication device A and the human who wears the communication device B Stands at a position opposite to each other and touches the fingertip of the arm wearing the communication device A with the fingertip of the arm wearing the communication device B, thereby enabling data communication between the pair of communication devices A and B. The present invention may be applied to an apparatus. Further, the present invention may be applied to a communication device other than for human body communication.

(A) shows the confirmation signal used for embodiment of this invention, (b) is a wave form diagram which similarly shows a starting signal. It is a wave form diagram which shows the transmission code used for the same as the above. It is a wave form diagram which shows the data packet used for the same as the above. It is explanatory drawing which shows the usage example of a communication apparatus same as the above. It is a block diagram which shows the structure of each communication apparatus same as the above. It is a wave form diagram of noise used for explanation same as the above. It is a wave form diagram which shows the other example of the confirmation signal used for the same as the above. (A) shows the confirmation signal used in the conventional example, and (b) is a waveform diagram showing the activation signal.

Explanation of symbols

6 Signal processing part (signal processing means)
A, B Communication device H Human body P1a, P1b, P2a, P2b Electrode

Claims (4)

  A pair of communication devices that perform data communication through the transmission path, and the communication device on the data receiving side notifies the other side communication device that it has received the start signal and the data has been received. A signal transmission means for transmitting a signal to a communication apparatus on the other side, and a communication apparatus on the data transmission side have a signal processing means for sampling and identifying a start signal and a confirmation signal at a constant period, and transmitting signals. The means is arranged after arranging two transmission codes having the longest length in the time axis direction among three kinds of transmission codes having a waveform in which the binary is inverted once and having different lengths in the time axis direction. Each of the activation signal and the confirmation signal is generated by adding a combination of two or more transmission codes that are longer in the time axis direction than one transmission code having the second longest length in the time axis direction. Communication characterized by Location.   2. The communication apparatus according to claim 1, wherein the signal transmission unit generates each of the activation signal and the confirmation signal by combining all types of the transmission codes.   The signal transmitting means creates a special code having a waveform in which binary values are inverted once and having a length longer in the time axis direction than a transmission code having the longest length in the time axis direction among the transmission codes, Each of the activation signal and the confirmation signal is generated by using a special code as a transmission code to be added after arranging two transmission codes having the longest length in the time axis direction among the transmission codes. The communication device according to claim 1 or 2.   Each of the communication devices has two electrodes, and at least one of the electrodes in both communication devices is in contact with different parts of the human body and forms the transmission path in a portion existing between each other in the human body. The communication apparatus according to any one of claims 1 to 3, wherein the communication apparatus is characterized in that:

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