JP2008016952A - Transmission/reception system, wireless transmission apparatus, and transmission/reception method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology of detecting a location of a wireless transmission apparatus by obtaining a communication distance between an external transmission/reception apparatus and the wireless transmission apparatus. <P>SOLUTION: The external transmission/reception apparatus 10 amplitude-modulates a carrier (transmits a transmission signal). The radio transmission apparatus sequentially generates a response signal including distance information. Further, the modulation factor in the radio transmission apparatus 20 is sequentially set in response to the distance information included in the response signal. Moreover, the carrier from the external transmission/reception apparatus 10 is load-modulated on the basis of each of the response signals. Consequently, the response signals whose amplitude levels differ from each other are sequentially transmitted. A prediction distance representing the distance information of each response signal is equivalent to a communication distance when a transmission level of the carrier from the external transmission/reception apparatus 10 and each receiving state of each response signal in the external transmission/reception apparatus 10 satisfy a prescribed condition. When the receiving state of each response signal satisfies the prescribed condition, the external transmission/reception apparatus 10 acquires the prediction distance represented by the distance information of each response signal as the communication distance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission / reception system in which a wireless transmission device and an external transmission / reception device communicate according to a load modulation method, a wireless transmission device that communicates with an external transmission / reception device according to a load modulation method, and a wireless transmission device according to a load modulation method. The present invention relates to a transmission / reception method executed with an external transmission / reception device.

  In recent years, a transmission / reception system in which an external transmission / reception device and a wireless transmission device exchange data signals in a non-contact manner using radio waves in a radio frequency band has been put into practical use. A typical example of a wireless transmission device is a so-called RFID (Radio Frequency Identification) tag. RFID tags are also called wireless tags, and are used in various frequency bands.

  For example, in a wireless tag (so-called IC card) having a communication frequency of 13.56 MHz, the following communication is performed between an external transmission / reception device (for example, a reader / writer) and a wireless transmission device (for example, a wireless tag). Is executed. Here, a case where the reply method from the wireless tag is a load modulation method will be described.

  First, in the reader / writer, a 13.56 MHz carrier wave is amplitude-modulated (Amplitude Shift Keying; ASK) based on transmission data, and an electromagnetic wave (or microwave) corresponding to the modulated carrier wave is transmitted from the transmission / reception coil.

  Next, in the wireless tag, the electromagnetic wave from the reader / writer is received by the transmission / reception coil, and power supply power for operation of the internal circuit is generated. Some wireless tags include a driving power source such as a battery. In that case, driving power may not be generated from a received signal. Also, transmission data is restored from the modulated carrier wave by the demodulation circuit, and the microcomputer mounted on the wireless tag reads reply data (for example, a data string stored in the storage unit) according to the transmission data. Further, the output circuit of the non-related tag amplitude-modulates a subcarrier (for example, a 212 KHz subcarrier) based on the return data, and changes the impedance to the transmission / reception coil in accordance with the modulation subcarrier.

  On the other hand, the reader / writer transmits an electromagnetic wave corresponding to a carrier wave having a constant amplitude. Here, according to the impedance change in the wireless tag, the impedance of the reader / writer with respect to the transmission / reception coil also changes. As a result, the carrier wave in the reader / writer is load-modulated, so that the sub-carrier corresponding to the return data is sent from the wireless tag.

  In this way, the reader / writer can acquire the information stored in the wireless tag in a non-contact manner.

  The range in which the external transmission / reception device can communicate with the wireless transmission device is determined by the strength of the signal (radio wave) from the external transmission / reception device. That is, in the conventional transmission / reception system, in order to ensure a certain communicable range, the external transmission / reception apparatus is set to transmit a signal at a certain level according to the communicable range.

The transmission / reception system can be applied to various fields. For example, a wireless tag is attached to the storage container, and data (for example, type, concentration, date of manufacture, etc.) relating to the contents (solid, liquid, or gas) stored in the storage container is stored in the wireless tag. . If it does in this way, the information regarding the contents can be easily acquired without contact, and the contents stored in the storage container can be recognized. Such recognition of the contents is necessary, for example, for a DMFC (direct methanol fuel cell) that generates power using a methanol aqueous solution as a direct fuel. In DMFC, it is important to manage the concentration of aqueous methanol solution that serves as fuel in order to generate electricity smoothly and obtain maximum output.
JP-A-9-130999

  However, in the conventional transmission / reception system, it is assumed that information can be surely exchanged between the external transmission / reception device and the wireless transmission device without contact. That is, it is assumed that the wireless transmission device exists in a communicable range (a range in which the external transmission / reception device and the wireless transmission device can communicate). Therefore, the case where the wireless transmission device does not exist within the communicable range is not discussed. In the conventional transmission / reception system, the wireless transmission device only communicates with the external transmission / reception device in response to a signal from the external transmission / reception device, and a device for detecting the location of the wireless transmission device has been proposed in the past. It has not been.

  In addition, when a product such as liquid or gas is stored and handled in a storage container, it is often required to manage the content of the contents stored in the storage container. For example, in DMFC, it is necessary to manage the remaining amount of aqueous methanol solution in order to continue power generation. In general, when the contents are liquid, the contents can be managed by estimating the liquid level based on the conductivity or dielectric constant of the contents, or by using ultrasonic reflection. There is a way to estimate the level. However, since the number of parts of the circuit for estimating the liquid level is large, the circuit scale is large and the cost is high, so that there is a problem that the practicality is low.

  An object of the present invention is to detect the location of a wireless transmission device. More specifically, an object of the present invention is to provide a system capable of managing the internal capacity by detecting the location of a wireless transmission device.

  According to one aspect of the present invention, an external transmission / reception device and a wireless transmission device communicate in a transmission / reception system. The external transmission / reception apparatus transmits a transmission signal by transmitting a carrier wave and modulating the carrier wave based on transmission data. The wireless transmission device performs load modulation on the carrier wave from the external transmission / reception device. The wireless transmission device includes a first transmission / reception unit, a first control unit, a reply signal supply unit, and a level setting unit. The first transmission / reception unit receives a carrier wave from the external transmission / reception device. Further, the first transmission / reception unit can change the modulation degree of the carrier wave during load modulation. When the transmission signal is received by the first transmission / reception unit, the first control unit sequentially outputs a plurality of reply information. Each of the return information includes distance information, and the distance information included in each of the return signals indicates different predicted distances. Upon receiving the reply information from the first control unit, the reply signal supply unit generates a reply signal based on the reply information and supplies the generated reply signal. The level setting unit sets the modulation degree in the first transmission / reception unit to the modulation degree corresponding to the distance information included in the reply information output to the reply signal supply unit. Further, the first transmission / reception unit sequentially transmits a plurality of return signals having different amplitude levels by load-modulating the carrier wave from the external transmission / reception device based on the return signal from the return signal supply unit. Each of the plurality of reply signals includes distance information. The external transmission / reception device includes a transmission signal supply unit, a second transmission / reception unit, a signal state detection unit, an information detection unit, and a second control unit. The return signal supply unit supplies a transmission signal by supplying a carrier wave and modulating the carrier wave based on transmission data. The second transmission / reception unit transmits the carrier wave from the transmission signal supply unit. The second transmitting / receiving unit receives a reply signal transmitted by load modulation in the external transmission / reception device. The signal state detection unit detects the reception state of the reply signal received by the second transmission / reception unit. The information detection unit detects distance information from the reply signal received by the second transmission / reception unit. The second control unit detects by the information detection unit that each of the amplitude level of the carrier wave transmitted by the second transmission / reception unit and the reception state of the return signal detected by the signal state detection unit satisfies a predetermined condition. The predicted distance indicated by the obtained distance information is acquired as the communication distance between the external transmission / reception device and the wireless transmission device.

  In the above transmission / reception system, the communication distance can be determined by the transmission level of the carrier wave transmitted from the external transmission / reception device, the reception state of the return signal, and the modulation degree in the wireless transmission device. Here, assuming that each of the transmission level of the carrier wave and the reception state of the return signal is in a predetermined state, the level setting unit determines the actual communication based on the correspondence between the communication distance and the modulation factor. The degree of modulation when the distance is the predicted distance indicated in the distance information can be set. That is, the predicted distance indicated by the distance information included in each of the return signals is such that the amplitude level of the carrier wave transmitted from the external transmission / reception device and the reception state of the return signal in the external transmission / reception device each satisfy a predetermined condition. It corresponds to the communication distance. Therefore, when the second control unit determines that the reception state of the reply signal satisfies the predetermined condition, the actual communication distance is the predicted distance indicated by the distance information included in the reply signal. Thus, since the distance to the wireless transmission device can be obtained, the location of the wireless transmission device can be detected.

  Preferably, in the level setting unit, the modulation degree in the first transmission / reception unit is the predicted distance indicated by the distance information included in the return information output to the return signal supply unit. The amplitude level of the carrier wave transmitted from the external transmission / reception device and the reception state of the return signal corresponding to the return information in the external transmission / reception device are set to the modulation degrees when the predetermined conditions are satisfied.

  Preferably, the level setting unit includes a communication distance and a modulation factor when the amplitude level of the carrier wave from the external transmission / reception device and the reception state of the return signal in the external transmission / reception device satisfy predetermined conditions. It has a level information correspondence table indicating the correspondence. The level setting unit selects, from the level information correspondence table, a modulation degree corresponding to the predicted distance indicated by the distance information included in the reply information output to the reply signal supply unit. The modulation degree is set to the selected modulation degree.

  In the above transmission / reception system, by referring to the level information correspondence table, when the actual communication distance is the predicted distance indicated by the distance information, the reception state of the return signal satisfies the predetermined condition in the external transmission / reception device. The degree of modulation can be grasped.

  Preferably, the external transmission / reception device further includes a reception amplification unit that amplifies the amplitude level of the reply signal received by the second transmission / reception unit to a predetermined level. The signal state detection unit measures the amplification degree of the reply signal by the reception amplification unit. The second control unit determines that the reception state of the return signal satisfies a predetermined condition when the amplification level of the return signal measured by the signal state detection unit is a predetermined amplification level.

  Preferably, the signal state detection unit counts the number of error portions occurring in the reply signal received by the second transmission / reception unit. The second control unit determines that the reception state of the return signal satisfies a predetermined condition when the number of error points counted by the signal state detection unit is a predetermined number.

Preferably, the signal state detection unit measures an amplitude level of a reply signal received by the second transmission / reception unit. The second control unit determines that the reception state of the return signal satisfies a predetermined condition when the amplitude level measured by the signal state detection unit is a predetermined level. Preferably, the return signal supply unit When receiving the return information from the first control unit, generates a return signal provided with a section corresponding to the return information and having a continuous amplitude level fluctuation, and supplies the generated return signal.

  In the transmission / reception system, the signal state detection unit can acquire an accurate reception state when the reception state of the return signal is detected in a section in which the fluctuation of the amplitude level continues. Thereby, it is possible to accurately determine whether or not the reception state of the reply signal satisfies a predetermined condition.

  Further, in order to generate a reply signal having a section in which the fluctuation of the amplitude level continues, for example, the reply signal supply unit connects a data string (measurement information) with a constant data value to the reply information, The return signal may be generated by modulating the subcarrier generated from the base station based on the concatenated data string. As a result, the amplitude level of the reply signal continuously fluctuates in the section corresponding to the measurement information in the reply signal. For example, the reply signal supply unit may generate a reply signal by multiplying a predetermined data string by a data string indicating a random data value. As a result, the amplitude level of the reply signal continuously fluctuates in the section of the reply signal multiplied by the random data string.

  Preferably, the transmission / reception system further includes a storage container. The storage container is provided with the wireless transmission device so that the predetermined content is stored and the communication distance is changed according to the increase or decrease of the content of the content. The second control unit further determines the content of the predetermined content based on the determined communication distance.

  In the above transmission / reception system, the control unit can derive the internal capacity from the communication distance in consideration of the relationship between the communication distance and the internal capacity. Thereby, the content volume of the content accommodated in the storage container can be managed.

  Preferably, the transmission / reception system further includes a storage container in which predetermined content that is liquid is stored, and a floating member that floats on a liquid surface of the predetermined content stored in the storage container. The wireless transmission device is provided on the surface of the floating member. The second control unit obtains the content of the predetermined content stored in the storage container based on the determined communication distance.

  In the transmission / reception system, the floating member moves up and down in accordance with the increase or decrease in the content of the contents stored in the storage container. Further, the communication distance also changes according to the fluctuation of the internal capacity. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the content volume of the content accommodated in the storage container can be managed. In order to make the relationship between the communication distance and the internal capacity unambiguous, for example, the second transmitting / receiving unit of the external transmission / reception device is moved to a position corresponding to the moving direction of the floating member (for example, the moving direction of the floating member). It may be arranged on the extension line).

  Preferably, the transmission / reception system further includes a storage container in which predetermined contents are stored, and a partition member. The partition member is disposed inside the storage container and moves in accordance with an increase or decrease in the internal volume of the predetermined content stored in the storage container. The wireless transmission device is provided on the partition member. The second control unit obtains the content of the predetermined content stored in the storage container based on the determined communication distance.

  In the transmission / reception system, the communication distance also changes according to the increase / decrease in the content of the contents stored in the storage container. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the content volume of the content accommodated in the storage container can be managed. In order to make the relationship between the communication distance and the internal capacity unambiguous, for example, the second transmitting / receiving unit of the external transmission / reception device is positioned at a position corresponding to the moving direction of the partition member (for example, the moving direction of the partition member). On the extension line).

  Preferably, the transmission / reception system further includes a storage container in which a predetermined content is stored and whose outer shape expands and contracts in accordance with an increase or decrease in the internal volume of the content. The wireless transmission device is provided on the surface of the container. The second control unit obtains the content of the predetermined content stored in the storage container based on the determined communication distance.

  In the transmission / reception system, the communication distance also changes according to the increase / decrease in the content of the contents stored in the storage container. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the content volume of the content accommodated in the storage container can be managed. In order to make the relationship between the communication distance and the internal capacity unambiguous, for example, the second transmission / reception unit of the external transmission / reception device is positioned corresponding to the expansion / contraction direction of the container (for example, on the extension line in the expansion / contraction direction). It should just be arranged.

  Preferably, the transmission / reception system further includes a fuel cell unit including a power generation unit that generates power using liquid fuel. The storage container stores liquid fuel used by the power generation unit. The second control unit determines an internal volume of the liquid fuel stored in the storage container based on the determined communication distance.

  In the transmission / reception system, the internal volume of the liquid fuel stored in the storage container can be managed.

  Preferably, the transmission / reception system further includes an infusion storage container for storing a predetermined infusion solution, a floating member floating on a liquid surface of the predetermined infusion solution stored in the infusion solution storage container, and a container mounting portion for attaching the infusion solution storage container. The wireless transmission device is provided on the surface of the floating member. The second control unit obtains the internal volume of the predetermined infusion contained in the infusion container based on the obtained communication distance.

  In the transmission / reception system, the floating member moves up and down in accordance with the increase / decrease in the volume of the infusion contained in the infusion container. Further, the communication distance also changes according to the fluctuation of the internal capacity. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the internal volume of the infusion accommodated in the infusion solution container can be managed. In order to make the relationship between the communication distance and the internal capacity unambiguous, for example, the second transmitting / receiving unit of the external transmission / reception device is positioned at a position corresponding to the moving direction of the floating member (for example, the container mounting portion of the container mounting stand). ).

  Preferably, the transmission / reception system further includes a printer. The printer includes a paper feed tray that accommodates printer paper and a printer main body. The printer main body includes a tray storage unit in which a paper feed tray is inserted to store the paper feed tray. The paper feed tray includes a paper feed tray main body, a paper feed plate, and an urging member. The paper feed plate is disposed inside the paper feed tray main body and on which printer paper is placed. The biasing member connects one end of the bottom surface of the paper feed tray main body and one end of the paper feed plate in the insertion direction of the paper feed tray, and biases the paper feed plate in a direction away from the bottom surface of the tray main body. The wireless transmission device is provided at one end of the sheet feeding plate. The second control unit obtains the number of printer papers stored in the paper feed tray based on the obtained communication distance.

  In the above transmission / reception system, when the number of printer sheets decreases, one end of the sheet feeding plate moves away from the bottom surface of the tray body by the restoring force of the spring. Thereby, the communication distance also changes. Considering the relationship between the communication distance and the number of sheets, the control unit can derive the number of sheets from the communication distance. As a result, the number of printer sheets stored in the sheet feed tray can be managed. In order to make the relationship between the communication distance and the number of sheets unambiguous, for example, the second transmission / reception unit of the external transmission / reception device is moved to a position corresponding to the moving direction of the sheet feeding plate (for example, the upper surface of the tray storage unit). ).

  Preferably, the transmission / reception system further includes a printer. The printer includes an ink cartridge that stores predetermined ink, a floating member that floats on a liquid surface of the ink stored in the ink cartridge, and a printer main body that has a cartridge holder portion that stores the ink cartridge therein. The wireless transmission device is provided on the surface of the floating member. The second control unit obtains the internal volume of the ink stored in the ink cartridge based on the obtained communication distance.

  In the transmission / reception system, the floating member moves up and down in accordance with the increase or decrease in the content of the ink stored in the ink cartridge. Further, the communication distance also changes according to the fluctuation of the internal capacity. Considering the relationship between the communication distance and the internal capacity, the control unit can derive the internal capacity from the communication distance. Thereby, the internal volume of the ink accommodated in the ink cartridge can be managed. In order to unify the relationship between the communication distance and the internal capacity, for example, the second transmission / reception unit of the external transmission / reception device may be installed at a position corresponding to the moving direction of the floating member.

  Preferably, the wireless transmission device further includes a storage unit that stores content information that is information regarding the content. The first control unit sequentially outputs a plurality of return information including the level information and the content information stored in the storage unit. The information acquisition unit further detects content information from the reply signal received by the second transmission / reception unit. The external transmission / reception device further includes a display unit that displays at least one of the content obtained by the second control unit and the content information acquired by the information acquisition unit.

  In the transmission / reception system, it is possible to visually manage the content of the contents and information about the contents.

  According to another aspect of the present invention, the wireless transmission device performs load modulation on a carrier wave from an external transmission / reception device. The wireless transmission device includes a transmission / reception unit, a control unit, a reply signal supply unit, and a level setting unit. The transmission / reception unit receives a carrier wave from the external transmission / reception device. The transmission / reception unit can change the modulation degree of the carrier wave during load modulation. When a predetermined modulated carrier wave is received by the transmission / reception unit, the control unit sequentially outputs a plurality of return information including distance information indicating different prediction distances. When the reply signal supply unit receives the reply information from the control unit, the reply signal supply unit generates a reply signal based on the reply information and supplies the generated reply signal. The level setting unit sets the modulation degree in the transmission / reception unit to the modulation degree corresponding to the distance information included in the reply information output to the reply signal supply unit. The transmission / reception unit sequentially transmits a plurality of return signals having different amplitude levels by load-modulating the carrier wave from the external transmission / reception device based on the return signal from the return signal supply unit. Each of the plurality of reply signals includes distance information. The predicted distance indicated in the distance information included in each of the plurality of reply signals is that the amplitude level of the carrier wave from the external transmission / reception device and the reception state of the reply signal in the external transmission / reception device each satisfy a predetermined condition. It corresponds to the communication distance.

  In the wireless transmission device, the communication distance can be determined by the transmission level of the carrier wave transmitted from the external transmission / reception device, the reception state of the return signal, and the modulation degree in the wireless transmission device. Here, assuming that each of the transmission level of the carrier wave and the reception state of the return signal is in a predetermined state, the level setting unit determines the actual communication based on the correspondence between the communication distance and the modulation factor. The degree of modulation when the distance is the predicted distance indicated in the distance information can be set. Therefore, when the external transmission / reception apparatus determines that the reception state of the reply signal satisfies the predetermined condition, the actual communication distance is the predicted distance indicated in the distance information included in the reply signal. Thus, since the distance to the wireless transmission device can be obtained, the location of the wireless transmission device can be detected.

  Preferably, the level setting unit has a modulation degree in the transmission / reception unit, the communication distance is a predicted distance indicated in the distance information included in the return information output to the return signal supply unit, and the external The amplitude level of the carrier wave transmitted from the transmission / reception device and the reception level of the return signal corresponding to the return information in the external transmission / reception device are set to the degree of modulation when the predetermined condition is satisfied.

  Preferably, the level setting unit includes a communication distance and a modulation factor when the amplitude level of the carrier wave from the external transmission / reception device and the reception state of the return signal in the external transmission / reception device satisfy predetermined conditions. It has a level information correspondence table indicating the correspondence. The level setting unit selects a modulation degree corresponding to the predicted distance indicated by the distance information included in the reply information output to the reply signal supply unit from the level information correspondence table, and sets the modulation degree in the transmission / reception unit. Set to the selected modulation factor.

  According to still another aspect of the present invention, a transmission / reception method includes: an external transmission / reception device that transmits a carrier wave; a wireless transmission device that modulates the carrier wave and can change a modulation degree of the carrier wave during load modulation; Executed by. The transmission / reception method includes a transmission step, a carrier wave reception step, a generation step, a reply step, a reply signal reception step, a signal state detection step, a detection step, and an acquisition step. In the transmission step, the external transmission / reception device transmits the transmission signal by transmitting the carrier wave and modulating the carrier wave based on the transmission data. In the carrier wave reception step, the wireless transmission device receives the carrier wave transmitted in the transmission step. In the generation step, when the transmission signal is received in the carrier wave reception step, the wireless transmission device sequentially generates a plurality of return signals including distance information indicating different prediction distances, and the distance information included in the return signal The modulation degree in the wireless transmission device is sequentially changed according to the predicted distance indicated by. In the reply step, the wireless transmission device performs load modulation on the carrier wave from the external transmission / reception device based on the reply signal generated in the generation step, thereby sequentially transmitting a plurality of reply signals having different amplitude levels. Each of the plurality of reply signals includes distance information. In the reply signal receiving step, the external transmission / reception apparatus receives the reply signal transmitted in the reply step. In the signal state detection step, the reception state of the return signal received in the return signal reception step is detected. In the detecting step, distance information is detected from the reply signal received in the reply signal receiving step. In the acquisition step, the distance information detected in the detection step indicates that each of the amplitude level of the carrier wave transmitted in the transmission step and the reception state of the return signal detected in the signal state detection step satisfies a predetermined condition. The predicted distance is acquired as a communication distance between the external transmission / reception device and the wireless transmission device.

  In the above transmission / reception method, the communication distance can be determined by the transmission level of the carrier wave transmitted from the external transmission / reception device, the reception state of the return signal, and the modulation degree in the wireless transmission device. Here, assuming that each of the transmission level of the carrier wave and the reception state of the return signal is in a predetermined state, in the generation step, based on the correspondence between the communication distance and the modulation factor, the actual communication distance It is possible to set the degree of modulation when is the predicted distance indicated in the distance information. That is, the predicted distance indicated by the distance information included in each of the return signals is such that the amplitude level of the carrier wave transmitted from the external transmission / reception device and the reception state of the return signal in the external transmission / reception device each satisfy a predetermined condition. It corresponds to the communication distance. Therefore, when it is determined in the obtaining step that the reception state of the reply signal satisfies the predetermined condition, the actual communication distance is the predicted distance indicated in the distance information included in the reply signal. Thus, since the distance to the wireless transmission device can be obtained, the location of the wireless transmission device can be detected.

  Preferably, in the generation step, the modulation degree in the wireless transmission device is transmitted from the external transmission / reception device when the communication distance is a predicted distance indicated by the distance information included in the reply signal. In addition, the amplitude level of the carrier wave and the reception level of the return signal in the external transmission / reception apparatus are set to the modulation degree when the predetermined condition is satisfied.

  As described above, since the communication distance between the external transmission / reception device and the wireless transmission device can be obtained, the location of the wireless transmission device can be detected. Moreover, the internal volume of the content accommodated in the predetermined storage container can be managed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

(Embodiment of the present invention)
<Overall configuration>
FIG. 1 shows an overall configuration of a transmission / reception system according to an embodiment of the present invention. In this system, a carrier wave of a predetermined frequency (here, 13.56 MHz) is exchanged between the external transmission / reception device 10 and the wireless transmission device 20 in accordance with the load modulation method. The external transmission / reception device 10 is, for example, a reader / writer. The wireless transmission device 20 is, for example, an RFID (Radio Frequency Identification) tag, and stores ID information that is a data string unique to itself.

  The external transmission / reception device 10 transmits a carrier wave. Further, the external transmission / reception device 10 amplitude-modulates the carrier wave based on information including a command for instructing a reply of ID information. That is, the external transmission / reception device 10 transmits a transmission signal including a command for instructing a reply of ID information.

  The wireless transmission device 20 responds to the transmission signal from the external transmission / reception device 10 and based on the return information (here, return information including ID information and distance information indicating the predicted distance). The carrier from is load modulated. By this load modulation, a component corresponding to the predetermined information is superimposed on the carrier wave. That is, the component corresponding to the predetermined information is transmitted. In the wireless transmission device 20, the predicted distance indicated in the distance information included in the reply information is sequentially updated. Along with the update of the predicted distance, the ratio (the modulation degree of the carrier wave) of the “variation amount of the carrier wave amplitude level (load modulation amount)” by the load modulation to the “carrier wave amplitude level” is sequentially changed. The change of the modulation degree is realized by adjusting the difference (impedance change amount) between the impedance at the time of modulation and the impedance at the time of non-modulation in the wireless transmission device 20. That is, the wireless transmission device 20 sequentially outputs a plurality of reply signals having different amplitude levels. The amplitude level of each of the plurality of reply signals corresponds to the predicted distance indicated in the distance information included in the reply signal. In addition, the predicted distance indicated by the distance information included in each of the plurality of return signals is determined based on a predetermined condition in which the amplitude level of the carrier wave transmitted from the external transmission / reception device 10 and the reception state of the return signal in the external transmission / reception device 10 This corresponds to the actual communication distance when.

  Further, the external transmission / reception device 10 acquires predetermined information (here, a reply signal generated based on the return information) by extracting a component corresponding to the predetermined information from the load-modulated carrier wave. The external transmission / reception device 10 detects distance information from the acquired reply signal. When the external transmission / reception device 10 senses reception of a reply signal from the wireless transmission device 20 (the reception state of the reply signal satisfies a predetermined condition), distance information detected from the reply signal indicates The predicted distance is acquired as the actual communication distance. The communication distance corresponds to the distance between the external transmission / reception device 10 and the wireless transmission device 20.

<Relationship between signal level and communication distance>
Here, the relationship between the signal level and the communication distance will be described.

  FIG. 2 shows the relationship between the communication distance and the amplitude level of the carrier wave received by the wireless transmission device 20 (the reception level of the transmission signal). As shown in FIG. 2, the amplitude level (reception level) of the signal received by the receiving apparatus increases as the amplitude level (transmission level) of the signal transmitted by the transmitting apparatus increases. In addition, the reception level decreases as the distance between the transmission-side device and the reception-side device increases. As the signal transmission level increases, the relationship between the signal reception level and the communication distance changes in order of “curve A”, “curve B”, and “curve C”. Further, when the transmission level is constant, the relationship between the reception level and the communication distance is, for example, a curve A. In this case, the signal reception level decreases to “L1”, “L2”, and “L3” as the communication distance increases to “D1”, “D2”, and “D3”.

  In the load modulation method, the amount of amplitude modulation of the carrier due to load modulation increases as the impedance change amount of the wireless transmission device 20 increases. That is, as the modulation degree increases, the transmission level of the reply signal increases. Further, as the distance between the external transmission / reception device 10 and the wireless transmission device 20 increases, the load modulation amount sensed by the external transmission / reception device 10 decreases. That is, the longer the communication distance, the lower the reception level of the return signal.

  From the above, “communication distance” means “amplitude level of carrier wave transmitted from external transmission / reception device 10 (transmission level of carrier wave)”, “degree of modulation in wireless transmission device 20”, and “external transmission / reception device 10 It can be expressed as a function of the load modulation amount of the carrier wave to be sensed (reception level of the return signal). Here, assuming that “transmission level of carrier wave” and “reception level of reply signal” are predetermined fixed values, the correspondence between “communication distance” and “degree of modulation” is uniquely determined. can do.

  In the load modulation method, the amplitude level of the return signal is amplified to a predetermined level in the external transmission / reception device 10 so that the return signal having a weak amplitude level can be appropriately processed in the external transmission / reception device 10. In this case, the smaller the amplitude level of the reply signal, the greater the degree of amplification of the reply signal in the external transmission / reception device 10.

  From the above, the “communication distance” can be expressed as a function of “the transmission level of the carrier wave”, “the modulation degree in the wireless transmission device 20”, and “the amplification degree of the return signal in the external transmission / reception device 10”. Here, assuming that “transmission level of carrier wave” and “amplification degree” are predetermined fixed values, the correspondence relationship between “communication distance” and “degree of modulation” can be uniquely determined. it can.

<Relationship between number of errors and communication distance>
Next, the correspondence between the number of signal error locations and the communication distance will be described.

  FIG. 3A shows the relationship between “communication distance” and “communication S / N” when the signal transmission level is constant. As described above, when the signal transmission level is constant, the signal reception level decreases as the communication distance increases. Here, assuming that the noise in the communication path between the external transmission / reception device 10 and the wireless transmission device 20 is constant, the communication S / N decreases as the communication distance increases, and the signal received by the reception-side device. It is easy for errors to occur.

  FIG. 3B shows the relationship between “error rate (error rate in a signal received by a receiving device)” and “communication S / N” when the signal transmission level is constant. When the signal transmission level is constant, the smaller the communication S / N, the higher the error rate in the signal received by the receiving device.

  FIG. 3C shows the relationship between “the number of error locations (the number of error locations generated in a signal received by the receiving apparatus)” and “communication distance” when the signal transmission level is constant. 3A and 3B, the longer the communication distance, the greater the number of error locations in the signal received by the receiving apparatus.

  From the above, the “communication distance” is expressed as a function of “the transmission level of the carrier wave”, “the degree of modulation in the wireless transmission device 20”, and “the number of error points in the return signal received by the external transmission / reception device 10”. Can do. Here, when “transmission level of carrier wave” and “number of error locations” are fixed values determined in advance, the correspondence between “communication distance” and “degree of modulation” can be uniquely determined. it can.

  In summary, “communication distance” can be expressed as a function of “transmission level of carrier wave”, “degree of modulation in wireless transmission device 20”, and “reception state of return signal”. Here, when the “carrier transmission level” and “return signal reception state” are in a predetermined state, the correspondence between “communication distance” and “degree of modulation” is uniquely determined. Can do.

<Internal configuration of external transmission / reception device>
FIG. 4 shows an internal configuration of the external transmission / reception apparatus 10 shown in FIG. The external transmission / reception device 10 includes a control unit 11, a transmission signal supply unit 12, a transmission / reception unit 13, a decoding unit 14, and a signal state detection unit 15.

  The control unit 11 is a microcomputer, for example, and outputs ID reply command information when receiving an information acquisition command from the host computer. The ID reply command information is a data string indicating a command for causing the wireless transmission device 20 to send a reply signal.

  The transmission signal supply unit 12 amplitude-modulates the carrier wave (here, the amplitude level is 100 V and the frequency is 13.56 MHz) based on the ID reply command information from the control unit 11. That is, the transmission signal supply unit 12 supplies a transmission signal including ID reply command information. When the transmission signal supply unit 12 completes the supply of the modulated carrier wave, the control unit 11 causes the transmission signal supply unit to supply a carrier wave having a constant amplitude (here, a carrier wave having an amplitude level of 100 V and a frequency of 13.56 MHz).

  The transmission / reception unit 13 includes a tuning capacitor C1, a series resistor R1, and a transmission / reception coil L1. The transmission / reception coil L1 transmits an electromagnetic wave corresponding to the carrier wave (transmission signal, constant amplitude carrier wave) supplied from the transmission signal supply unit 12. That is, the transmission / reception unit 13 transmits a transmission signal (or a constant amplitude carrier wave). Further, when load modulation is executed in the wireless transmission device 20, a component corresponding to predetermined information is superimposed on the constant amplitude carrier wave in the transmission / reception unit 13. That is, the transmission / reception unit 13 receives a reply signal from the wireless transmission device 20. Here, the reply signal includes ID information unique to the wireless transmission device and distance information indicating the predicted distance.

  The decoding unit 14 extracts a component corresponding to the return signal from the load-modulated carrier wave. In addition, the decoding unit 14 performs amplification, demodulation, and decoding of the amplitude level on the extracted reply signal to generate reply information, and detects ID information and distance information from the generated reply information.

  The signal state detection unit 15 detects the reception state of the reply signal received by the transmission / reception unit 13 (the amplification degree of the reply signal, the number of error parts of the reply signal, the reception level of the reply signal, etc.).

  Further, the control unit 11 determines whether or not the reception state of the return signal detected by the signal state detection unit 15 satisfies a predetermined condition, whether or not the ID information is detected by the decoding unit 14, and the distance by the decoding unit 14 Whether or not a return signal is received is determined based on whether or not information is detected.

  Further, when the control unit 11 determines that “there is reception”, the control unit 11 acquires the predicted distance indicated in the distance information detected by the decoding unit 14 as an actual communication distance. The control unit 11 outputs measurement result information including the acquired communication distance and the ID information detected by the decoding unit 14 to the host computer.

<< Internal configuration of transmission signal supply unit >>
FIG. 5 shows an internal configuration of the transmission signal supply unit 12 shown in FIG. The transmission signal supply unit 12 includes an encoding processing unit 101, an error correction code addition unit 102, a transmission data generation unit 103, and a modulation circuit 104.

  The encoding processing unit 101 encodes the ID reply command information from the control unit 11 to generate transmission data.

  The error correction code adding unit 102 performs a predetermined operation on the transmission data generated by the encoding processing unit 101 to generate an error correction code. The error correction code is, for example, a Reed-Solomon code. Thereafter, the error correction code adding unit 102 adds the generated error correction code to the transmission data.

  The transmission data generation unit 103 adds a header to the transmission data (transmission data to which the error correction code is added) from the error correction code addition unit 102. The header includes a synchronization signal and a communication start identifier.

  The modulation circuit 104 modulates a carrier wave based on transmission data (transmission data with a header added) from the transmission data generation unit 103. For example, the modulation circuit 104 supplies a carrier wave having a high amplitude level (for example, a carrier wave having an amplitude level of 100 V) to the transmission / reception unit 13 during a period in which the data value of the transmission data from the transmission data generation unit 103 is “1”. In the period when the data value of the transmission data is “0”, a carrier wave having a relatively low amplitude level (for example, a carrier wave having an amplitude level of 90 V) is supplied to the transmission / reception unit 13. This carrier wave is generated by an oscillator (not shown) or the like. In this way, the modulation circuit 104 supplies the modulated carrier wave to the transmission / reception unit 13. The transmission / reception unit 13 transmits an electromagnetic wave corresponding to the modulated carrier wave.

  In addition, when the transmission data output from the transmission data generation unit 103 is completed, the modulation circuit 104 receives a control from the control unit 11 and supplies a constant amplitude carrier wave. Thereby, the transmission / reception part 13 transmits the electromagnetic waves according to a fixed amplitude carrier wave.

<< Internal Configuration of Decoding Unit and Signal State Detection Unit >>
FIG. 6 shows an internal configuration of the decoding unit 14 and the signal state detection unit 15 shown in FIG. The decoding unit 14 includes a reception amplification circuit 105, a demodulation circuit 106, an error correction circuit 107, a decoding processing unit 108, and an information detection unit 109. The signal state detection unit 15 includes an amplification degree calculation unit 110 and an error location counting circuit 111.

  The reception amplifier circuit 105 extracts a component (reply signal) corresponding to predetermined information from the carrier wave subjected to load modulation in the transmission / reception unit 13. Here, the reception amplifier circuit 105 extracts a predetermined frequency band (here, a frequency band corresponding to the data value “1” of the reply data, which is 13.56 MHz ± 212 kHz).

  Further, the reception amplifier circuit 105 amplifies the amplitude level of the extracted reply signal to a predetermined level. For example, the reception amplification circuit 105 amplifies the return signal with reference to the transmission level of a carrier wave having a constant amplitude supplied by the transmission signal supply unit 12. Further, for example, the reception amplifier circuit 105 may automatically adjust the amplitude level of the return signal so that it always becomes a constant amplitude of 1 Vp-p regardless of the amplitude level of the carrier wave.

  The demodulation circuit 106 demodulates the reply signal amplified by the reception amplification circuit 105 and generates reply data. Note that a header and an error correction code are added to the reply data.

  The error correction circuit 107 executes error correction processing on the return data using the error correction code added to the return data from the demodulation circuit 106.

  The decoding processing unit 108 decodes the reply data that has been corrected by the error correction circuit 107, and generates reply information. Here, the reply information includes ID information and distance information of the wireless transmission device 20.

  The information detection unit 109 detects ID information and distance information from the reply information generated by the decoding processing unit 108.

  The amplification degree calculation unit 110 obtains the amplification degree of the reply signal in the reception amplification circuit 105. For example, the amplification degree calculation unit 110 compares the “amplitude level of the reply signal before amplification” (the amplitude level of the reply signal extracted by the reception amplification circuit 105) with respect to the “amplitude level of the constant amplitude carrier wave” supplied by the transmission signal supply unit 12. ) ". For example, the amplification degree calculation unit 110 quantifies the ratio of the amplitude level of the reply signal before amplification to the amplitude level 1Vp-p.

  The error location counting circuit 111 counts the number of error locations that have occurred in the reply data that is error-corrected by the error correction circuit 107.

<Internal configuration of wireless transmission device>
FIG. 7 shows an internal configuration of the wireless transmission device 20 shown in FIG. The wireless transmission device 20 includes a storage unit 21, a transmission / reception unit 22, a voltage generation unit 23, a decoding unit 24, a control unit 25, a reply signal supply unit 26, a modulation degree selection unit 27, and a level setting unit. 28.

  The storage unit 21 is, for example, an EEPROM, and stores a data string indicating ID information unique to the wireless transmission device 20.

  The transceiver 22 includes a transceiver coil L2, a tuning capacitor C2, a variable resistor R2, and a switch SW. When the transmission / reception coil L2 receives an electromagnetic wave from the external transmission / reception device 10, an AC voltage corresponding to the electromagnetic wave is generated in the transmission / reception unit 22 by electromagnetic induction. That is, the transmission / reception unit 22 receives a transmission signal from the external transmission / reception device 10.

  The voltage generator 23 includes a rectifier diode D3, a smoothing capacitor C3, and a Zener diode ZD. The voltage generation unit 23 generates a drive voltage that drives each block in the wireless transmission device 20 using the AC voltage generated in the transmission / reception unit 22. Specifically, when an AC voltage generated in the transmission / reception unit 22 is input to the voltage generation unit 23, the rectifier diode D3 and the smoothing capacitor C3 rectify the AC voltage to generate a DC voltage. Further, the Zener diode ZD limits the voltage level of the DC voltage so that the DC voltage generated by the rectifier diode D3 and the smoothing capacitor C2 becomes a predetermined level. Zener diode ZD suppresses the voltage level so that the voltage level of the DC voltage is lower than the upper limit level when the voltage level is higher than a predetermined upper limit level. In this way, a drive voltage is generated, and each block in the wireless transmission device 10 is driven. In addition, the voltage level of the drive voltage can be kept within a predetermined range, and each block can be prevented from being destroyed due to the voltage being too high.

  The decoding unit 24 demodulates and decodes the transmission signal received by the transmission / reception unit 22 to generate ID reply command information.

  The control unit 25 reads the ID information stored in the storage unit 21 according to the ID reply command information generated by the decryption unit 24. Then, the control unit 25 sequentially outputs a plurality of distance information indicating different predicted distances to the modulation degree determination unit 27 and returns a plurality of return information including the distance information and the ID information read from the storage unit 21 as a reply signal. The data are sequentially output to the supply unit 26. Specifically, when the output of the distance information and the reply information is completed, the control unit 25 updates the predicted distance indicated in the distance information. That is, when the control unit 25 senses reception of the transmission signal by the transmission / reception unit 22, the control unit 25 sequentially outputs a plurality of distance information indicating different prediction distances and sequentially outputs reply information including the distance information.

  The return signal supply unit 26 supplies the component to be superimposed on the carrier wave based on the return information generated by the control unit 25. Here, the return signal supply unit 26 modulates the subcarrier (here, 212 kHz (= 13.56 MHz / 64)) and supplies the modulated subcarrier. That is, the reply signal supply unit 26 supplies a reply signal corresponding to reply information (distance information and ID information). The subcarrier is generated by, for example, a subcarrier generation unit (not shown) in the wireless transmission device 20. The subcarrier generation unit generates a clock signal from the carrier wave received by the transmission / reception unit 22, and generates a subcarrier by dividing the clock signal.

  The modulation degree selection unit 27 selects a modulation degree corresponding to the predicted distance indicated in the distance information output from the control unit 25, and outputs level information indicating the selected modulation degree to the level setting unit 28. Specifically, the modulation degree selection unit 27 has a level information correspondence table indicating a correspondence relationship between the prediction distance and the modulation degree, and the modulation degree corresponding to the prediction distance indicated in the distance information is selected from the level information correspondence table. Select and output level information indicating the selected degree of modulation.

  The level setting unit 28 sets the resistance value of the variable resistor R <b> 2 so that the modulation degree in the transmission / reception unit 22 becomes the modulation degree indicated by the level information output from the modulation degree selection unit 27. Thereby, the amplitude modulation amount of the carrier wave by the load modulation in the transmission / reception unit 22 also changes. That is, the level setting unit 28 sets the modulation degree of the carrier wave in the transmission / reception unit 22 to a modulation degree corresponding to the predicted distance indicated by the distance information from the control unit 25. Specifically, the level setting unit 28 determines the modulation degree in the transmission / reception unit 22 and the amplitude of the carrier wave transmitted from the external transmission / reception device 10 when the actual communication distance is the predicted distance indicated by the distance information of the reply information. The level and the reception level of the reply signal (reply signal corresponding to the reply information) in the external transmission / reception device 10 are set to the modulation degree when each of the reception conditions satisfies a predetermined condition.

  In the transmission / reception unit 22, the switch SW is turned on / off according to the return signal from the return signal supply unit 26. When the switch SW is turned on / off, the impedance of the transmission / reception unit 22 changes, and the carrier wave is load-modulated in the transmission / reception unit 22. Thereby, a component corresponding to the reply signal is superimposed on the carrier wave. Further, the load modulation amount of the carrier wave is determined by the impedance change amount (here, the resistance value of the variable resistor R2). That is, the transmission / reception unit 22 transmits a reply signal in which the amplitude level is set by the level setting unit 28. Each amplitude level of the reply signal corresponds to the predicted distance indicated in the distance information included in the reply signal. Here, assuming that the amplitude level of the carrier wave transmitted from the external transmission / reception device 10 is a predetermined level, the predicted distance is determined so that each of the reception states of the return signal satisfies the predetermined condition in the external transmission / reception device 10. It corresponds to the communication distance when

  The modulation degree selection unit 27 and the level setting unit 28 may be integrated. That is, the level setting unit 28 has a level information correspondence table, and selects a modulation degree corresponding to the predicted distance indicated in the distance information included in the return information from the control unit 25 from the level information correspondence table. The degree of modulation (resistance value of the variable resistor R2) may be set.

<Level information correspondence table>
FIG. 8 shows an example of the level information correspondence table. The level information correspondence table includes “communication distance” and “communication distance” when the transmission level of the carrier wave transmitted from the external transmission / reception device 10 is a fixed level and the reception state of the return signal sensed by the external transmission / reception device 10 is fixed. Correspondence relationship with “degree of modulation” is shown. Here, when the reception state of the reply signal is fixed, for example, when the amplification degree of the reply signal is a fixed value, when the reception level of the reply signal is a fixed level, or when the number of error parts in the reply signal is This means a fixed number. In the level information correspondence table, the modulation degree corresponding to the communication distance increases as the communication distance increases.

The level information correspondence table is created, for example, according to the following procedure.
[Step 1]: The amplitude level of the carrier wave transmitted by the external transmission / reception device 10 is set to a fixed level, and a desired condition to be satisfied by the reception state of the return signal in the external transmission / reception device 10 (for example, a desired amplification degree of the return signal) ).
[Step 2]: A communication distance between the external transmission / reception device 10 and the wireless transmission device 20 is set.
[Step 3]: The reception state of the return signal in the external transmission / reception device 10 (for example, the amplification degree of the return signal in the external transmission / reception device 10) is monitored while adjusting the modulation degree.
[Step 4]: The modulation degree when the reception state of the return signal in the external transmission / reception device 10 satisfies the desired condition determined in [Step 1] is associated with the communication distance set in [Step 2].

<< Internal Configuration of Decoding Unit >>
FIG. 9 shows an internal configuration of the decoding unit 24 shown in FIG. The decoding unit 24 includes a demodulation circuit 201, an error correction circuit 202, and a decoding processing unit 203.

  The demodulation circuit 201 demodulates the transmission signal received by the transmission / reception unit 22 to generate transmission data. Note that a header and an error correction code are added to the transmission data.

  The error correction circuit 202 uses the error correction code added to the transmission data generated by the demodulation circuit 201 to perform error correction processing on the transmission data.

  The decoding processing unit 203 decodes the transmission data that has been corrected by the error correction circuit 202, and generates ID reply command information. The ID reply information command is supplied to the control unit 25.

<< Internal Configuration of Reply Signal Supply Unit >>
FIG. 10 shows an internal configuration of the reply signal supply unit 26 shown in FIG. The reply signal supply unit 26 includes an encoding processing unit 204, an error correction code addition unit 205, a reply data generation unit 206, and a modulation circuit 207.

  The encoding processing unit 204 encodes the reply information from the control unit 25 and generates reply data.

  The error correction code adding unit 205 performs a predetermined operation on the reply data generated by the encoding processing unit 204 to generate an error correction code. Then, the error correction code adding unit 205 adds the generated error correction code to the reply data.

  The reply data generation unit 206 adds a header to the reply data from the error correction code addition unit 205 (reply data to which the error correction code is added). The header includes a synchronization signal and a communication start identifier.

  The modulation circuit 207 turns on / off the switch SW of the transmission / reception unit 22 based on the reply data. For example, the switch SW is turned on when the output from the modulation circuit 207 is “H level”, and turned off when the output from the modulation circuit 207 is “L level”. Here, the modulation circuit 207 turns on / off the switch SW of the transmission / reception unit 22 at a specific frequency (here, 212 kHz subcarrier) during a period in which the data value of the return data from the return data generation unit 206 is “1”. The switch SW is turned off during the period when the data value of the reply data is “0”. That is, in this case, the modulation circuit 207 modulates the subcarrier based on the return data, and supplies the modulated subcarrier to the switch SW of the transmission / reception unit 22 as a return signal.

  For example, as shown in FIGS. 11A to 11C, in the wireless transmission device 20, the subcarrier (FIG. 11A) is modulated based on the return data (FIG. 11B) to become a modulated subcarrier (FIG. 11C). Also, as shown in FIGS. 11D and 11E, the carrier SW (FIG. 11D) is load-modulated by turning on / off the switch SW of the transmission / reception unit 22 according to the modulation subcarrier, and the component corresponding to the modulation subcarrier is constant. It is superimposed on the amplitude carrier wave (FIG. 11E). In the external transmission / reception device 10, the component corresponding to the modulation subcarrier is extracted by the reception amplification circuit 105 as shown in FIG. 11F.

<Operation>
Next, the operation of the transmission / reception system according to the present embodiment will be described. Here, when the control unit 25 senses reception of a transmission signal (when ID reply command information is received), the control unit 25 increases the predicted distance indicated by the distance information step by step from “D1”. That is, when the output of the distance information indicating the predicted distance “D1” is completed, the control unit 25 next outputs the distance information indicating the predicted distance “D2”. In addition, the amplitude level of the constant amplitude carrier wave transmitted from the external transmission / reception device 10 is assumed to be a predetermined level (a fixed level set when the level information correspondence table is created) (in this case, the carrier wave). The transmission level of the above satisfies a predetermined condition).

  First, in the external transmission / reception device 10, the ID reply command information is output from the control unit 11, and the transmission signal supply unit 12 supplies a transmission signal corresponding to the ID reply command information. The transmission / reception unit 13 transmits the transmission signal supplied from the transmission signal supply unit 12. When transmission of the transmission signal by the transmission signal supply unit 12 is completed, the control unit 11 causes the transmission signal supply unit 12 to transmit a constant amplitude carrier wave. The transmission / reception unit 13 transmits the constant amplitude carrier wave supplied from the transmission signal supply unit 12.

  On the other hand, in the wireless transmission device 20, the transmission signal from the external transmission / reception device 10 is received by the transmission / reception unit 22, and the decoding unit 24 generates ID reply command information from the transmission signal. When receiving the ID reply command information from the decoding unit 24, the control unit 25 reads the ID information from the storage unit 21, and generates reply information including the read ID information and distance information indicating the predicted distance “D1”. Next, the control unit 11 outputs distance information indicating the predicted distance “D1” to the modulation degree selecting unit 27 and returns reply information including the read ID information and distance information (predicted distance “D1”) as a reply signal. Output to the supply unit 26. The reply signal supply unit 26 supplies a reply signal corresponding to reply information including ID information and distance information (predicted distance “D1”). The modulation degree selection unit 27 selects the modulation degree “gain1” corresponding to the predicted distance “D1”. The level setting unit 28 sets the resistance value of the variable resistor R2 so that the degree of modulation in the transmission / reception unit 22 is “gain1”. Thereby, the transmission / reception unit 22 transmits a return signal including distance information indicating the predicted distance “D1” and having an amplitude level corresponding to the predicted distance “D1”.

In addition, when the output of the distance information indicating the predicted distance “D1” and the reply information is completed, the control unit 25 updates the predicted distance indicated in the distance information from “D1” to “D2”. Accordingly, the reply signal supply unit 26 supplies a reply signal corresponding to reply information including distance information indicating the predicted distance “D2”, and the level setting unit 28 has a modulation degree “gain2” (predicted distance “ The resistance value of the variable resistor R2 is updated so that the degree of modulation corresponds to “D2”. Therefore, the transmission / reception unit 22 transmits a reply signal including distance information indicating the predicted distance “D2” and having an amplitude level corresponding to the predicted distance “D2”. A plurality of reply signals having different levels are sequentially transmitted. Each of the plurality of reply signals includes distance information, and the amplitude level of each reply signal corresponds to the predicted distance indicated in the distance information included in the reply signal.

  On the other hand, in the external transmission / reception device 10, the reply signal received by the transmission / reception unit 13 is processed by the decoding unit 14 to become reply information. The decoding unit 14 detects ID information and distance information from the reply information. Further, the signal state detection unit 15 detects the reception state of the reply signal. Specifically, the amplification degree calculation unit 110 obtains the amplification degree of the reply signal, and the error part counting circuit 111 counts error parts in the reply signal.

  In the control unit 11, the ID information and the distance information are detected by the decoding unit 14, and the reception state of the return signal detected by the signal state detection unit 15 is set as a predetermined condition (for example, a desired condition when creating the level information correspondence table). If it is determined that the set reception state is satisfied, it is determined that “reception is present”. For example, when the amplification degree obtained by the amplification degree calculation unit 110 is smaller than a predetermined value (amplification degree set as a desired condition when the level information correspondence table is created), the control unit 11 determines that the return signal reception state is predetermined. Judge that the conditions are met.

  Here, if the control unit 11 determines that “reception is present”, the control unit 11 acquires the predicted distance indicated by the distance information detected by the decoding unit 14 (information detection unit 109) as an actual communication distance. Next, the control unit 11 writes the acquired communication distance and the ID information detected by the decoding unit 14 (information detection unit 109) in the measurement result information, and outputs the measurement result information to the host computer. Thereby, the host computer can grasp the distance between the external transmission / reception device 10 and the wireless transmission device 20.

<< About judgment of reception status >>
Note that the control unit 11 can also determine whether or not a return signal has been received based on the number of error locations in the return signal. In this case, when the control unit 11 determines that the number of error locations counted by the error location counting circuit 111 is less than a predetermined number (number of error locations set as a desired condition when the level information correspondence table is created), “there is a reception. Is determined.

  Further, the control unit 11 can determine whether or not a return signal has been received based on the reception level of the return signal. In this case, the amplification degree calculation unit 110 measures the amplitude level of the reply signal extracted by the reception amplification circuit 105 and outputs the measured amplitude level to the control unit 11. When the control unit 11 determines that the reception level measured by the amplification degree calculation unit 110 is higher than a predetermined level (reception level set as a desired condition when the level information correspondence table is created), the control unit 11 determines “reception is present”.

<< Communication distance calculation >>
For example, when the control unit 11 first determines that “reception has occurred” when receiving a return signal including distance information indicating the predicted distance “D2”, the control unit 11 acquires the predicted distance “D2” as the actual communication distance. . Since the amplitude level of a reply signal (for example, a reply signal including distance information indicating the predicted distance “D3”) transmitted subsequent to the reply signal is increased step by step, the control unit 11 “receives”. Will be judged. However, here, it is only necessary to obtain the distance information when it is first determined that “reception is present”, and therefore it is not necessary to process subsequent reply signals.

<< About reception determination >>
When the control unit 11 detects the ID information and the distance information and determines that the reception state of the return signal satisfies a predetermined condition, the control unit 11 determines that “reception is present”. On the other hand, even if the ID information and the distance information are detected, the control unit 11 does not determine that “there is reception” when the reception state of the return signal does not satisfy the predetermined condition. Further, the control unit 11 does not determine that “reception is present” if the ID information and the distance information are not detected even if the reception state of the return signal satisfies the predetermined condition. Thus, by determining whether or not a return signal is received based on whether or not ID information is detected, the communication distance to a specific wireless transmission device can be obtained even if a plurality of wireless transmission devices 10 exist. Can do. In addition, after sequentially sending reply signals to a plurality of wireless transmission devices and receiving reply signals from all the wireless transmission devices, a communication distance with each of the plurality of wireless transmission devices can be obtained. Is possible.

<Effect>
As described above, the communication distance can be obtained based on the state of the return signal, and the location of the wireless transmission device can be detected. In addition, the communication distance can be obtained and information stored in the wireless transmission device can be acquired.

  In the present embodiment, the case where the predicted distance indicated by the distance information increases step by step each time a reply signal is transmitted has been described. However, even when the predicted distance decreases step by step, the communication distance can be obtained. Is possible. In this case, the control unit 11 may acquire the predicted distance indicated by the distance information included in the reply signal that is finally determined to be “received” as the actual communication distance.

  Furthermore, information other than the ID information (for example, information on a product to which the wireless transmission device is attached) may be written in the storage unit 21 of the wireless transmission device 20.

  Further, the relationship between the modulation degree (for example, the resistance value of the variable resistor R2) and the communication distance (predicted distance) can be expressed as a mathematical expression. Therefore, the level setting unit 28 performs the predetermined calculation based on the relationship between the modulation degree and the predicted distance to the distance information output from the control unit 25 without using the level information correspondence table, so that the level setting unit 28 May be set.

(Modification of control unit)
Further, as shown in FIG. 12, the control unit 25 may include an ID information reading unit 208, a level information output unit 209, a distance information generation unit 210, and a reply information generation unit 211. When receiving the ID reply command information from the decryption unit 24, the ID information reading unit 208 reads the ID information stored in the storage unit 21. Upon receiving the ID reply command information from the decoding unit 24, the level information output unit 209 sequentially outputs a plurality of level information indicating different degrees of modulation to the distance information generation unit 210 and the level setting unit 28. The distance information generation unit 210 has a level information correspondence table. When the level information is received from the level information output unit 209, the distance information generation unit 210 determines the communication distance corresponding to the modulation degree indicated by the level information from the level information correspondence table. It detects, generates distance information in which the detected communication distance is written as a predicted distance, and outputs the generated distance information to the reply information generation unit 211. The reply information generation unit 211 generates reply information including the ID information read by the ID information reading unit 208 and the distance information generated by the distance information generation unit 210, and the generated reply information is sent to the reply signal supply unit 26. Output to. In the case of such a configuration, the processing by the amplitude level determination unit 28 becomes unnecessary.

(Modification of load modulation method)
Note that the component superimposed on the carrier wave may be reply data instead of the subcarrier modulated based on the reply data. In this case, the modulation circuit 207 outputs the reply data from the reply data generation unit 206 to the switch SW of the transmission / reception unit 22 at a predetermined transfer rate (transfer rate corresponding to the frequency of the subcarrier). The modulation circuit 207 turns on the switch SW in a section where the data value of the reply data is “1”, and turns off the switch SW in a section where the data value of the reply data is “0”. That is, in this case, the modulation circuit 207 supplies the reply data as a reply signal to the switch SW of the transmission / reception unit 22.

  For example, as shown in FIGS. 13A and 13B, in the wireless transmission device 20, the modulation circuit 207 outputs reply data to the switch SW of the transmission / reception unit 22 based on the frequency of the subcarrier. Further, as shown in FIGS. 13C and 13D, the switch SW of the transmission / reception unit 22 is turned on / off according to the reply data, so that the carrier wave is load-modulated, and the component corresponding to the reply data is superimposed on the constant amplitude carrier wave. . In the external transmission / reception device 10, the component corresponding to the reply data is extracted by the reception amplification circuit 105 as shown in FIG. 13E.

(Modification 1 of this embodiment)
Referring to FIGS. 11A to 11F, in the wireless transmission device 20, the carrier wave is load-modulated by the subcarrier in the interval where the data value of the return data is “1”, and the data value of the return data is “0”. Load modulation is not performed in the section. Here, when the section where the data value of the reply data is “0” becomes longer, the section where the amplitude fluctuation of the carrier wave continuously occurs becomes shorter. In this case, for example, in the external transmission / reception device 10, the section in which the amplification of the reply signal is continued by the reception amplification circuit 105 is shortened, and the section in which the amplification degree is measured by the amplification degree calculation unit 110 is shortened. There is a risk that it is difficult to accurately determine the degree of amplification.

<Configuration>
In the transmission / reception system according to the first modification of the present embodiment, the operation by the return signal supply unit 26 (see FIG. 7) of the wireless transmission device 20 is different. In the first modification, when the reply signal supply unit 26 supplies a reply signal based on the reply information, the reply signal supply unit 26 further adds a data string (measurement information) having a constant data value to the reply data. Thereafter, the reply signal supply unit 26 modulates the subcarrier based on the reply data to which the measurement information is added. Specifically, the reply data generation unit 206 (see FIG. 10) of the reply signal supply unit 26 adds a header to the reply data from the error correction code adding unit 205 and further adds measurement information. .

<Operation>
Next, the operation of the transmission / reception system according to the first modification will be described with reference to FIGS. 14A to 14E. Here, processing from the generation of a reply signal to the determination of the reception state of the reply signal will be described.

  In the wireless transmission device 20, the reply data generation unit 206 outputs reply data to which the header, error correction code, and measurement information are added in order from the top. Specifically, the header, measurement information, reply data, and error correction code are output in this order (FIG. 14B).

  The modulation circuit 207 continues to output the subcarrier (FIG. 14A) while receiving the measurement information from the reply data generation unit 206. That is, while the modulation circuit 207 receives the measurement information, the modulation circuit 207 outputs a subcarrier whose amplitude level is not modulated (outputs the subcarrier as it is). That is, the subcarrier is continuously output in the section corresponding to the measurement information (FIG. 14C).

  In the external transmission / reception device 10, the carrier wave (FIG. 14D) in the transmission / reception unit 13 is load-modulated. At this time, in the section corresponding to the measurement information, the amplitude level of the load-modulated carrier wave continuously fluctuates (FIG. 14E), and the reception amplifier circuit 105 continuously extracts the subcarrier component ( FIG. 14F). Therefore, the reception amplifier circuit 105 can continuously amplify the subcarrier component (reply signal), and can secure a section in which the amplification factor is measured by the amplification factor calculation unit 110. As a result, the amplification factor calculation unit 110 can accurately determine the amplification factor, and the control unit 11 can determine whether or not a return signal has been received based on the accurate amplification factor.

<Effect>
As described above, by providing a section in which the amplitude level is not modulated in the reply signal, it is possible to secure a section in which the amplification degree of the reply signal can be accurately measured. In this section, it is also possible to accurately count error locations in the reply signal. Thereby, it is possible to accurately determine whether or not the reception state of the reply signal satisfies a predetermined condition.

(Modification 2 of this embodiment)
As shown in FIGS. 13A to 13F, when the return data is superimposed on the carrier wave by load modulation, the interval corresponding to the data value “1” and the interval corresponding to the data value “0” in the load modulated carrier wave are uniform. If the distribution is biased toward one side, the amplitude fluctuation amount of the carrier due to load modulation is not constant, and the amplitude fluctuation amount fluctuates. As a result, the reception amplification circuit 105 cannot accurately detect the amplitude fluctuation amount (amplitude level of the reply signal) and cannot accurately amplify the reply signal. It is difficult to accurately determine

<Configuration>
In the transmission / reception system according to the second modification of the present embodiment, the operation by the return signal supply unit 26 (see FIG. 7) of the wireless transmission device 20 is different. In the second modification, the reply signal supply unit 26 multiplies the reply data by the M-sequence code when supplying the reply signal based on the reply information. The M-sequence code is a data string in which a data value “1” and a data value “0” are randomly generated. Specifically, the reply data generation unit 206 (see FIG. 10) multiplies the reply data to which the header and the error correction code are added by the M-sequence code. The M-sequence code is used to make the occurrence probability of each of the data values “1” and “0” uniform in the entire reply data.

<Operation>
Next, the operation of the transmission / reception system according to the second modification will be described with reference to FIGS. 15A to 15F. Here, processing from the generation of a reply signal to the determination of the reception state of the reply signal will be described.

  The reply data generation unit 206 of the wireless transmission device 20 multiplies the reply data (FIG. 15B) to which the header and the error correction code are added by the M-sequence code. Next, reply data generation section 206 outputs reply data multiplied by the M-sequence code to modulation circuit 207 in accordance with the frequency of the subcarrier (FIG. 15A). In the section of the reply data multiplied by the M-sequence code, the occurrence probability of each of the data value “1” and the data value “0” is the same (FIG. 15C).

  In the external transmission / reception device 10, the carrier wave (FIG. 15D) in the transmission / reception unit 13 is load-modulated. Of the load modulated carrier wave, the section corresponding to the data value “1” and the section corresponding to the data value “0” are uniformly distributed in the section multiplied by the M-sequence code (FIG. 15E). Therefore, in the section multiplied by the M-sequence code, the reception amplifier circuit 105 can accurately detect the reception level of the reply signal and can accurately extract the reply signal (FIG. 15F). Therefore, the reception amplification circuit 105 can accurately amplify the reply signal, and a section in which the amplification degree calculation unit 110 can accurately measure the amplification degree can be secured. Thereby, the control part 11 can determine the presence or absence of reception of a reply signal based on an exact amplification degree.

  Further, the demodulation circuit 106 performs an operation for removing the M-sequence code when demodulating the reply signal from the reception amplification circuit 105. That is, the demodulation circuit 106 demodulates the reply signal from the reception amplifier circuit 105 to generate reply data, and then multiplies the reply data by the reciprocal of the M-sequence code.

<Effect>
As described above, it is possible to accurately measure the amplification degree of the reply signal by providing the reply signal with a section in which the section corresponding to the data value “1” and the section corresponding to the data value “0” are uniformly distributed. Can be secured. In this section, it is also possible to accurately count error locations in the reply signal. Thereby, it is possible to accurately determine whether or not the reception state of the reply signal satisfies a predetermined condition.

  Compared with the first modification, the data amount of the reply signal returned from the wireless transmission device 20 does not need to be increased, and thus the communication time can be shortened.

  FIG. 15C shows an example in which the data values “1” and “0” are generated alternately and continuously in order to help understanding of the present embodiment, but the data values “1” and “0” are illustrated. "May occur irregularly (may occur randomly). That is, the number of data values “1” and the number of data values “0” are equal (or substantially equal) within the section multiplied by the M-sequence code. In general, there are more examples in which the data values “1” and “0” are irregularly generated.

  In the description of the above embodiment, while the external transmission / reception device 10 completes transmission of the transmission signal and transmits a carrier wave having a constant amplitude (that is, the operation mode of the external transmission / reception device 10 is “read operation”). During a period of time, carrier load modulation is performed (that is, a return signal is transmitted), but carrier wave load modulation is performed during a period in which the amplitude level of the carrier wave from the external transmission / reception device 10 is not constant. Is also possible. In this case, both the “writing operation” and the “reading operation” are executed in the external transmission / reception device 10. According to this, the time required for communication can be shortened. This method in which both the “write operation” and the “read operation” are performed simultaneously is very effective for shortening the time for one-to-multiple communication, not one-to-one communication.

(Application example 1)
<Configuration>
FIG. 16 shows a configuration of a container management system to which the transmission / reception system according to the present embodiment is applied. The container management system includes an external transmission / reception device 10, a wireless transmission device 20, a storage container 30, and a display device 40. This system manages the contents (liquid) stored in the storage container 30.

[Container 30]
The storage container 30 includes a container body 301 and a floating member 302.

  The container main body 301 has, for example, a shape with a constant cross-sectional area (for example, a cubic shape, a rectangular parallelepiped shape, a cylindrical shape, etc.) and accommodates a liquid.

  The floating member 302 is a plate-like member having a size of several millimeters square, and is floating on the liquid surface of the liquid stored in the container main body 301. The floating member 302 is made of a material having a lower density or specific gravity than the liquid stored in the storage container 301. However, since the floating member 302 only needs to float on the surface of the liquid, the density of the floating member 302 does not need to be lighter than the liquid density. If the surface tension can float on the liquid surface, the density of the floating member 302 is low. It may be heavier than the liquid density. The floating member 302 moves up and down in accordance with an increase or decrease in the internal volume of the liquid stored in the container body 301.

  The wireless transmission device 20 is installed on the surface of the floating member 302.

[External transmission / reception device 10]
The transmission / reception coil L1 of the external transmission / reception device 10 is arranged at a position corresponding to the moving direction of the floating member 302 as a loop-shaped transmission / reception antenna. Here, the transmission / reception coil L1 is disposed on the upper portion of the container 30 located on the extension line in the moving direction of the floating member 302.

  Further, the control unit 11 of the external transmission / reception device 10 calculates the internal volume of the liquid stored in the storage container 30 based on the obtained communication distance. The “distance D1 from the external transmission / reception device 10 to the bottom surface of the container body 301” and the “bottom area S1 of the container body 301” are constant, and the control unit 11 stores these values in advance. In addition, the control unit 11 outputs management information in which the detected ID information and the obtained liquid volume are written instead of the measurement result information to the display device 40.

[Display device 40]
The display device 40 displays management information (ID information, liquid content) from the external transmission / reception device 10.

[Wireless transmission apparatus 20]
FIG. 17 shows an installation example of the wireless transmission device 20 in the floating member 302. The wireless transmission device 20 is formed as an IC chip, for example, and is installed on the surface of the floating member 302 of the container 30. The transmission / reception coil L2 of the wireless transmission device 20 is arranged as a looped transmission / reception antenna. Here, if the entire surface of the floating member 302 is subjected to a waterproof treatment or a water repellent treatment, not only the IC chip can be protected but also the floating property can be improved.

<Operation>
Next, the operation of the container management system shown in FIG. 16 will be described.

  First, various signals (transmission signal, reply signal) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20, and the control unit 11 of the external transmission / reception device 10 obtains the communication distance D2.

  Next, the control unit 11 subtracts the “communication distance D2” from the “distance D1” stored therein in advance to obtain the “distance (liquid level) D3 from the bottom surface of the container body 301 to the liquid surface”. calculate. Next, the control unit 11 calculates the internal volume of the liquid stored in the storage container 30 by multiplying the calculated “liquid level D3” by the “bottom area S1 of the container main body 301”. Next, the control unit 11 writes the ID information detected by the information detection unit 109 and the calculated liquid volume in the management information, and outputs the management information to the display device 40.

  Next, the display device 40 displays management information (ID information, liquid content) from the external transmission / reception device 10.

  Here, as shown in FIG. 18, when the internal volume of the liquid stored in the storage container 30 decreases, the floating member 302 in which the wireless transmission device 20 is installed descends. As a result, the distance between the external transmission / reception device 10 and the wireless transmission device 20 becomes long, so that the state of the reply signal received by the external transmission / reception device 10 deteriorates (the reception level decreases). Therefore, compared with the case of FIG. 16, the communication distance D2 calculated | required by the external transmission / reception apparatus 10 becomes long, and the calculated liquid content volume reduces. That is, the liquid content displayed on the display device 40 decreases.

<Effect>
As described above, the content of the contents stored in the storage container can be measured from the communication distance between the external transmission / reception device and the wireless transmission device. Moreover, the content accommodated in the storage container can be identified by acquiring the ID information. Thereby, the kind and content of the content accommodated in the storage container can be managed simultaneously.

  If the storage unit 21 of the wireless transmission device 20 stores the content information, the control unit 25 of the wireless transmission device 20 sends the content information together with the ID information to the return information (the source of the reply signal). It is also possible to write in the information). The content information is information about the content stored in the storage container 30 such as the type of content and the date of manufacture. In this case, if the content information is acquired together with the ID information by the information detection unit 109, the quality control can be performed simultaneously with the measurement of the liquid content.

  Further, the position where the transmission / reception coil L <b> 1 of the external transmission / reception device 10 is arranged is not limited to the upper part of the container 30. If the distance between the external transmission / reception device 10 and the wireless transmission device 20 is uniquely determined with respect to the change in the liquid level, the transmission / reception coil L1 of the external transmission / reception device 10 may be disposed beside the container 30. Absent.

  In addition, the amplitude level of the transmission signal from the external transmission / reception device 10 is determined when the distance from the wireless transmission device 20 is maximum (the housing container 30 becomes empty and the floating member 302 reaches the bottom surface of the container body 301). However, it is preferable that the wireless transmission device 20 is set so as to transmit a reply signal in response to the transmission signal. In this way, it is possible to determine whether the state of the return signal has deteriorated due to factors other than the communication distance (for example, device failure or communication failure due to radio wave shielding). Further, since it can be confirmed whether or not the receiving container 30 is mounted based on the presence / absence of a reply signal, the mounting confirmation component is not necessary.

  In this application example, the case where the cross-sectional area of the container main body 301 is constant is shown. However, if the relationship between the liquid level D3 and the volume of liquid contained is determined in advance, the cross-sectional area is not constant. May be.

<Installation location of IC tag>
As shown in FIG. 19, three wireless transmission devices 20-1, 20-2 and 20-3 may be arranged on the floating member 302. In this case, the external transmission / reception device 10 is based on the communication distance d1 with the wireless transmission device 20-1, the communication distance d2 with the wireless transmission device 20-2, and the communication distance d3 with the wireless transmission device 20-3. To measure the communication distance D2. According to this, even when the liquid level is inclined, the communication distance can be accurately measured. This is particularly effective when the container is attached to a portable electronic device.

(Variation 1 of the container)
Further, as shown in FIG. 20, the same effect can be obtained when the storage container 30 </ b> A is used instead of the storage container 30 shown in FIG. 16. The storage container 30A includes a container main body 301A and a partition wall member 302A. The partition member 302A moves along the height direction of the container main body 301A according to the increase or decrease of the liquid stored in the container main body 301A. In addition, the transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the moving direction of the partition wall member 302A. Here, the transmission / reception coil L1 is disposed above the storage container 30A, which is an extension of the partition member 302A in the moving direction. Accordingly, the communication distance D2 can be measured even when the storage container 30A is tilted. Moreover, since airtightness can be ensured, it is possible to prevent the liquid as the contents from leaking to the outside or the outside air from entering the housing container 30A even when the housing container 30A is tilted.

(Variation 2 of the container)
Further, as shown in FIG. 21, the same effect can be obtained when the storage container 30 </ b> B is used instead of the storage container 30 shown in FIG. 16. The storage container 30B expands and contracts in accordance with an increase or decrease in the internal volume of the liquid stored in itself (see FIG. 22). Here, the storage container 30B expands and contracts in the height direction. The wireless transmission device 20 is installed on the extended line in the expansion / contraction direction (here, the upper surface of the storage container 30B) on the surface of the storage container 30B. The transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the expansion / contraction direction of the container 30B. Here, it arrange | positions above the container 30B which is on the extension line | wire of an expansion-contraction direction. According to this, even if the whole container management system inclines, the communication distance D2 can be measured. Further, since the wireless transmission device 20 is lightweight, the influence of the weight of the wireless transmission device 20 on the shape of the storage container 30B is small, and measurement errors can be reduced. Further, if the upper surface of the container 30B can be made substantially parallel to the external transmission / reception device 10, the communication distance D2 can be measured with high accuracy. Further, the storage container 30B may be entirely formed of the same members and materials, but the members and materials may be partially different. According to this, the degree of deformation in each part of the storage container 30B can be adjusted so that the upper surface of the storage container 30B is substantially parallel to the external transmission / reception device 10.

(Application example 2)
<Configuration>
FIG. 23 shows a configuration of a fuel cell system to which the transmission / reception system according to the present embodiment is applied. The fuel cell system includes a container 30, a wireless transmission device 20, a fuel cell unit 50, and an electronic device 60. In this system, the fuel cell unit 50 generates power using the aqueous methanol solution stored in the storage container 30 as fuel, and the electronic device 60 is driven by the power of the fuel cell unit 50 and manages the aqueous methanol solution stored in the storage container 30. . The electronic device 60 is, for example, a notebook personal computer.

[Container 30]
The storage container 30 stores a methanol aqueous solution. The storage unit 21 of the wireless transmission device 20 provided in the floating member 302 stores methanol information as content information in addition to the ID information. The methanol information is information relating to the aqueous methanol solution stored in the storage container 30, such as the concentration of the aqueous methanol solution. The reply signal includes methanol information in addition to the ID information.

[Fuel cell unit 50]
The fuel cell unit 50 includes a power generation unit 500 and an external transmission / reception device 10. The power generation unit 500 includes a fuel supply pump 501, a DMFC power generation cell 502, and a voltage conversion circuit 503.

  The fuel supply pump 501 sucks out the methanol aqueous solution from the container 30 and supplies the sucked methanol aqueous solution to the power generation cell 502. The power generation cell 502 generates power using the aqueous methanol solution supplied from the fuel supply pump 501. The voltage conversion circuit 503 converts the electric power generated by the power generation cell 502 into a voltage suitable for the electronic device 60 and supplies the converted electric power to the electronic device 60.

  The information detection unit 109 of the external transmission / reception device 10 detects methanol information in addition to the ID information.

  The controller 11 calculates the internal volume of the aqueous methanol solution stored in the storage container 30 based on the determined communication distance. In addition, the control unit 11 outputs management information in which the ID information and methanol information detected by the information detection unit 109 and the calculated content of the aqueous methanol solution are written to the electronic device 60 instead of the measurement result information. Further, the control unit 11 outputs a remaining amount decrease signal to the electronic device 60 when the content of the aqueous methanol solution stored in the storage container 30 becomes equal to or less than the specified amount.

[Electronic device 60]
The electronic device 60 includes a control microcomputer 601 and a display unit 602. The control microcomputer 601 receives management information from the external transmission / reception device 10 and outputs the management information to the display unit 602. Further, when the control microcomputer 601 receives the remaining amount decrease signal from the external transmission / reception device 10, it outputs a warning display command.

  The display unit 602 displays management information (ID information, methanol information, content of methanol aqueous solution) from the control microcomputer 601. Further, when receiving a warning display command from the control microcomputer 601, the display unit 602 displays a remaining amount reduction notification image. The remaining amount decrease notification image is an image for notifying that the remaining amount of the aqueous methanol solution is small, such as “the remaining amount of fuel“ low ””.

<Operation>
Next, the operation of the fuel cell system shown in FIG. 23 will be described.

  When the power generation operation by the fuel cell unit 50 is started, various signals (transmission signal, reply signal) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20 to control the external transmission / reception device 10. The unit 11 periodically obtains the communication distance D2. Moreover, the control part 11 calculates the content volume of the methanol aqueous solution accommodated in the storage container 30 based on the calculated | required communication distance. Next, the control unit 11 writes the ID information and methanol information detected by the information detection unit 109 and the obtained volume of the aqueous methanol solution in the management information, and periodically outputs the management information to the electronic device 60. Thereby, the management information (ID information, methanol information, content of methanol aqueous solution) displayed on the display unit 602 of the electronic device 60 is periodically updated.

  Further, when the control unit 11 determines that the calculated internal volume of the aqueous methanol solution is equal to or less than the specified amount, the control unit 11 outputs a remaining amount decrease signal to the control microcomputer 601. Therefore, “remaining amount“ low ”” is displayed on the display unit 602. Thereby, it is possible to prompt the user of the electronic device 60 to change the fuel or refill the fuel.

<Effect>
As described above, the content of the aqueous methanol solution can be measured from the communication distance between the external transmission / reception device and the wireless transmission device. Moreover, the methanol aqueous solution accommodated in the container can be identified by acquiring the methanol information. Thereby, the kind and content volume of methanol aqueous solution can be managed simultaneously.

  In addition, by referring to the methanol information as the contents information, it is possible to prevent erroneous use of aqueous methanol solutions having different specifications. In other words, the content information displayed on the display unit 602 can include information on conformity / nonconformity of the content with respect to the fuel cell system.

  Further, in the fuel cell system for electronic devices, the container 30 is relatively small. Here, since the floating member 302 provided with a wireless transmission device (for example, a wireless tag) can be manufactured with a size of about several millimeters square, it can also be used for a small container 30. That is, it can be applied to a small container.

  In addition, it is possible to replace conventional components for content management (liquid level measurement using the conductivity and dielectric constant of contents or reflection of ultrasonic waves) with a small and lightweight wireless transmission device. It becomes. As a result, fuel information of the fuel cell system (fuel concentration, characteristics of contents, number of cartridge recycles, etc.) can be stored, and at the same time, sharing as a component for managing the internal capacity can be realized. In this way, an excellent effect of reducing the size and weight of the storage container can be obtained. In addition, since the conventional components for the internal volume management method are not necessary, the space for storing the fuel can be increased. Thereby, prolonged operation of the fuel cell system can be realized.

  In addition, although methanol aqueous solution was mentioned as an example as a fuel, it is not restricted to methanol, Liquids, such as a solution which melt | dissolved borohydride in alkaline aqueous solution, can also be used as fuel instead of methanol.

  Further, information regarding the liquid level measured periodically may be stored in the external transmission / reception device 10 and the wireless transmission device 20. Further, the expected remaining driving time of the fuel cell system can be obtained from the stored liquid level information and the measured elapsed time.

  Moreover, it may replace with the storage container 30 shown in FIG. 23, and may provide the storage container shown in FIG.20 and FIG.21.

  The transmission / reception system can be applied not only to the fuel cell system but also to a system that is easily within the scope of those skilled in the art. For example, it can be used to store liquids, such as storage containers for petroleum fuel (for example, kerosene, gasoline), fuel tanks for automobiles, storage containers for edible seasonings, oil, soup, liquor, etc. It is. As a large one, it can be used in a crude oil storage tank having a floating lid.

  Further, the present invention can be applied to cases other than the case where the content is a liquid (for example, a case where a solid is stored like rice bran). In this case, as the container, for example, a form as shown in FIGS. 20 and 21 is preferable. 20 and 21 can be applied even when the contents are gas.

(Application example 3)
<Configuration>
FIG. 24 shows a configuration of an infusion management system to which the transmission / reception system according to the present embodiment is applied. The infusion management system includes an infusion pack 71, an infusion stand 72, a wireless transmission device 20, an external transmission / reception device 10, an information transmission device 73, and a display device 40. This infusion management system is applied to an infusion pack used for infusion at a medical site such as a hospital.

[Infusion pack 71]
The infusion pack 71 stores the infusion. A floating member 302 is floating on the liquid level of the infusion contained in the infusion pack 71.

[Infusion stand 72]
The infusion stand 72 includes a support column 72a that extends substantially vertically from the installation surface, and a pack attachment 72b that protrudes from the tip of the support column 72a. The infusion pack 71 is attached to the attachment hook of the pack attachment portion 72b.

[Wireless transmission apparatus 20]
The wireless transmission device 20 is installed on the surface of the floating member 302 that floats in the infusion pack 71. The storage unit 21 of the wireless transmission device 20 stores infusion information as content information in addition to the ID information. Infusion information is, for example, information on infusion, such as the type, concentration, volume, expiration date of use, information on infusion pack containers, etc. The reply signal includes infusion information in addition to the ID information.

[External transmission / reception device 10]
The transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the moving direction of the floating member 302 in a state where the infusion pack 71 is attached to the infusion stand 72. Here, the transmission / reception coil L1 is disposed on the pack attachment portion 72b of the infusion stand 72, which is on the extension line in the moving direction of the floating member 302.

  Moreover, the information detection part 109 of the external transmission / reception apparatus 10 detects infusion information in addition to ID information. The control unit 11 calculates the internal volume of the infusion contained in the infusion pack 71 based on the determined communication distance. The control unit 11 stores in advance a content correspondence table created based on the relationship between the communication distance and the content of the infusion. In the internal capacity correspondence table, a plurality of internal capacity and a plurality of communication distances are associated. In the internal capacity correspondence table, the internal capacity corresponding to the communication distance decreases as the communication distance increases. Instead of the measurement result information, the control unit 11 outputs the measurement result information in which the ID information and the infusion information detected by the information detection unit 109 and the calculated infusion volume are written to the information transmission device 73.

  Moreover, the control part 11 will output the residual amount reduction signal to the information transmission apparatus 73, if the content volume of infusion is below a regulation amount. Further, the control unit 11 stores in advance patient information, which is information related to the patient, such as the type of infusion to be administered to the patient, and the infusion information detected by the information detection unit 109 and the patient information stored in itself. If they do not match, a warning signal is output to the information transmission device 73.

[Information transmission device 73]
The information transmission device 73 transmits various signals (management information, remaining amount reduction signal, warning signal) from the external transmission / reception device 10 to the display device 40. Here, when the information transmission device 73 and the display device 40 communicate wirelessly, a frequency that does not interfere with the communication between the external transmission / reception device 10 and the wireless transmission device 20 may be employed. Communication between the information transmission device 73 and the display device 40 may be performed by wire.

[Display device 40]
The display device 40 is installed in a hospital room or a nurse station. The display device 40 displays management information (ID information, infusion information, infusion volume) from the information transmission device 73. Further, when the display device 40 receives the remaining amount reduction signal from the information transmission device 73, the display device 40 displays a remaining amount reduction notification image. In addition, when receiving a warning signal from the information transmission device 73, the display device 40 displays an infusion nonconformity notification image. The infusion solution non-conformity notification image is an image notifying that the infusion pack is not correctly assigned to the patient, for example, “infusion pack non-conformity”.

<Operation>
Next, the operation of the infusion management system shown in FIG. 24 will be described.

  When the infusion pack 71 is attached to the infusion stand 72, various signals (transmission signals, reply signals) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20, and the external transmission / reception device 10 is controlled. The unit 11 periodically obtains the communication distance. Moreover, the control part 11 calculates | requires the content volume of the infusion accommodated in the infusion pack 71 based on the calculated | required communication distance. For example, the control unit 11 detects the internal capacity corresponding to the communication distance from the internal capacity correspondence table stored in itself. Next, the control unit 11 writes the ID information and the infusion information detected by the information detection unit 109 and the obtained infusion volume in the management information, and periodically outputs the management information to the information transmission device 73.

  Next, the information transmission device 73 transmits the management information from the external transmission / reception device 10 to the display device 40. Thereby, the management information (ID information, infusion information, infusion volume) displayed on the display device 40 is periodically updated.

  Moreover, if the control part 11 of the external transmission / reception apparatus 10 determines with the content volume of the calculated | required infusion being below a regulation amount, it will output a residual amount reduction signal. Therefore, “remaining amount“ low ”” is displayed on the display device 40. Thereby, attention of drip exchange can be urged.

  Further, when the control unit 11 determines that the patient information stored in advance in itself does not match the infusion information detected by the information detection unit 109, the control unit 11 outputs a warning signal. Therefore, “not compatible with infusion pack” is displayed on the display device 40. Thereby, attention of drip incompatibility can be urged.

<Effect>
As described above, the type and content of the infusion contained in the infusion pack can be managed simultaneously. Moreover, since the remaining amount of the infusion pack assigned to each patient can be managed, the timing of infusion exchange for many patients can be grasped. In this case, the information transmission device 73 and the display device 40 may be wirelessly communicated, and the display device 40 may be carried by a nurse or a doctor as being small and portable. This frees nurses and doctors from the troublesome work associated with running out of infusion. Further, by referring to the infusion information as the contents information, it is possible to collate whether or not the infusion is suitable for the patient. Therefore, it is possible to prevent a medical error such as injecting the wrong infusion to the patient. In other words, the contents information displayed on the display device 40 can include information on conformity / nonconformity of the contents with respect to the infusion management system.

  Moreover, since the floating member 302 provided with the wireless transmission device can be manufactured with a size of about several millimeters square, it can also be used for a small infusion pack 71. That is, it can be applied to a small infusion pack.

  The display device 40 may emit a warning sound together with the remaining amount reduction notification image and the infusion nonconformity notification image. Moreover, you may provide the alarm device which emits a warning sound separately. In this application example, the display device 40 is installed in a hospital room, a nurse station, or the like, but may be attached to the information transmission device 73, the external transmission / reception device 10, the infusion stand 72, or the like. Furthermore, the information transmission device 73 and the external transmission / reception device 10 may be integrated.

  In this application example, the example using the internal capacity correspondence table is shown, but the internal capacity corresponding to the communication distance may be obtained using a calculation formula.

  Each device (external transmission / reception device 10, information transmission device 73, etc.) installed on the infusion stand 72 may be a type in which power is supplied from an outlet or a cordless type using a rechargeable battery. good.

  Furthermore, in this application example, an infusion pack used for infusion is given as an example, but the infusion in this application example includes blood. That is, the present invention can also be applied to a blood transfusion pack used for blood transfusion. In this case, if the storage unit 21 of the wireless transmission device 20 stores information related to blood type, it is possible to manage the remaining amount of blood for blood transfusion and blood type. As a result, similar to the infusion management system in this application example, it is possible to prevent a medical error such as transfusion of wrong blood to the patient. Further, the present system is not limited to medical use, and can be applied to an infusion management system using a liquid other than medical use.

  Alternatively, the wireless transmission device 20 may be suspended on the infusion surface of the infusion pack 71 in a state of being housed in a capsule using the same material as that constituting the infusion pack 71 instead of being installed on the floating member 302. good.

(Application example 4)
<Configuration>
Next, a paper management system to which the transmission / reception system according to the present embodiment is applied will be described. The paper management system manages printer paper accommodated in the printer.

  FIG. 25 is an external view of the printer 80. This paper management system includes an external transmission / reception device 10, a wireless transmission device 20, a paper feed tray 81, and a printer main body 82. The printer main body 82 is formed with a concave tray storage portion 800. The paper feed tray 81 is inserted into the tray storage unit 800 and stored in the tray storage unit 800.

[Paper Tray 81]
FIG. 26 is a schematic cross-sectional view of the paper feed tray 81. The paper feed tray 81 includes a rectangular box-shaped tray main body 801, a rectangular paper feed plate 802, and an elastic body (for example, a spring) 803 as an urging member. The sheet feeding plate 802 is disposed inside the tray main body 801 (specifically, the upper portion of the bottom surface 801a of the tray main body 801), and the printer paper is placed thereon. The spring 803 is connected between one end of the paper feed plate 802 and one end of the bottom surface 801 a of the tray main body 801 in the insertion direction of the paper feed tray 81. Due to the restoring force of the spring 803, one end of the sheet feeding plate 802 is biased in a direction away from the bottom surface 801 a of the tray body 801.

[Wireless transmission apparatus 20]
The wireless transmission device 20 is installed at one end of the paper feed plate 802 in the insertion direction of the paper feed tray 81. The storage unit 21 of the wireless transmission device 20 stores sheet information as content information in addition to the ID information. The paper information is information relating to the printer paper such as the type and size of the printer paper. Note that the reply signal includes paper information in addition to the ID information.

[Printer body 82]
FIG. 27 is a schematic cross-sectional view of the printer main body 82. The printer main body 82 includes an external transmission / reception device 10 and a display unit 804.

[External transmission / reception device 10]
The transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the moving direction of the sheet feeding plate 802. Here, the transmission / reception coil L1 is installed on the upper surface portion 800a of the tray storage portion 800, which is an extension line in the moving direction of one end portion of the sheet feeding plate 802.

  The information detection unit 109 of the external transmission / reception device 10 detects paper information in addition to the ID information. The control unit 11 obtains the number of printer sheets stored in the sheet feed tray 81 based on the obtained communication distance. The control unit 11 stores in advance a number correspondence table created based on the relationship between the communication distance and the number of printer sheets. In the number correspondence table, a plurality of sheets and a plurality of communication distances are associated with each other. In the number correspondence table, the longer the communication distance, the larger the number of sheets corresponding to the communication distance. Further, the control unit 11 outputs, to the display unit 804, management information in which the ID information detected by the information detection unit 109 and the sheet information and the obtained number of sheets are written instead of the measurement result information.

  In addition, the control unit 11 outputs a remaining amount decrease signal to the display unit 401 when the obtained number of sheets is equal to or less than the specified amount.

  The display unit 804 displays management information (ID information, paper information, the number of sheets) from the external transmission / reception device 10. In addition, when the display unit 804 receives the remaining amount decrease signal from the external transmission / reception device 10, the display unit 804 displays a remaining amount decrease notification image (for example, the remaining amount “low”).

<Operation>
Next, the operation by the paper management system will be described.

  When the paper feed tray 81 is stored in the tray storage unit 800 of the printer main body 82, various signals (transmission signals and reply signals) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20, and externally. The control unit 11 of the transmission / reception device 10 periodically obtains a communication distance. Further, the control unit 11 obtains the number of printer papers stored in the paper feed tray 81 based on the obtained communication distance. For example, the control unit 11 detects the number of sheets corresponding to the communication distance from the number correspondence table. Next, the control unit 11 writes the ID information and paper information detected by the information detection unit 109 and the obtained number of sheets in the management information, and periodically outputs the management information to the display unit 804. As a result, the management information displayed on the display unit 804 is periodically updated.

  Here, when the number of printer papers stored in the paper feed tray 81 decreases, one end of the paper feed plate 802 moves upward of the tray main body 801 (that is, the upper surface of the tray storage unit 800 by the restoring force of the spring 803). Part 800a). Therefore, the state of the reply signal from the wireless transmission device 20 is improved. Thereby, the communication distance D2 calculated | required by the external transmission / reception apparatus 10 becomes short, and the calculated number of sheets reduces. That is, the number of sheets displayed on the display unit 804 is reduced.

  If the control unit 11 of the external transmission / reception device 10 determines that the obtained number of sheets is equal to or less than the specified amount, the control unit 11 outputs a remaining amount reduction signal. Therefore, “remaining amount“ low ”” is displayed on the display unit 804. Thereby, it is possible to prompt the user to replenish paper. Note that the display unit 804 may emit a warning sound together with the remaining amount decrease signal.

<Effect>
As described above, the type and number of sheets stored in the sheet feed tray can be managed simultaneously. If the paper information is displayed on the display screen of the personal computer, it is possible to prevent the paper having different sizes from being specified when printing from the personal computer.

  In addition, since a wireless transmission device (for example, a wireless tag) can be manufactured with a size of about several millimeters square, it can be mounted in an arbitrary space in a paper feed tray.

  In this application example, an example using the number correspondence table is shown, but the number of sheets corresponding to the communication distance may be obtained using a calculation formula.

  In this application example, the communication distance is periodically obtained. However, if the communication distance is obtained according to the operation of the printer body, the measurement of the communication distance when the printer is not operating can be omitted. Can do.

(Application example 5)
<Configuration>
Next, an ink management system to which the transmission / reception system according to the present embodiment is applied will be described. This ink management system manages ink contained in an ink cartridge built in an ink jet printer.

  FIG. 28A is an external view of an inkjet printer. A cartridge holder portion 91 is formed in the printer main body 90. This ink management system includes an external transmission / reception device 10, a wireless transmission device 20, a cartridge holder 91, and an ink cartridge 92. FIG. 28B is an external view of the cartridge holder portion 91. The ink cartridge 92 is attached in the cartridge holder portion 91. FIG. 29 is a schematic sectional view of the cartridge holder portion 91 and the ink cartridge 92.

[Ink cartridge 92]
The ink cartridge 92 stores ink. In addition, a floating member 302 floats on the liquid level of the ink stored in the ink cartridge 92.

[Wireless transmission apparatus 20]
The wireless transmission device 20 is installed on the surface of the floating member 302. The storage unit 21 of the wireless transmission device 20 stores ink information as content information in addition to the ID information. Ink information is information about ink, such as the color and type of ink, for example. The return signal includes ink information in addition to the ID information.

[External transmission / reception device 10]
The transmission / reception coil L1 of the external transmission / reception device 10 is disposed at a position corresponding to the moving direction of the floating member 302. Here, the transmission / reception coil L1 is disposed on the upper portion of the cartridge holder portion 91 which is on an extension line in the movement direction.

  The information detection unit 109 of the external transmission / reception device 10 detects ink information in addition to the ID information. The control unit 11 obtains the internal volume of the ink stored in the ink cartridge 92 based on the obtained communication distance. In addition, the control unit 11 outputs management information in which the ID information and ink information detected by the information detection unit 109 and the obtained ink content are written, instead of the measurement result information, to the display unit 901.

  In addition, the control unit 11 outputs a remaining amount decrease signal to the display unit 901 when the ink content is equal to or less than the specified amount.

  The display unit 901 displays management information (ID information, ink information, ink content) from the external transmission / reception device 10. In addition, when the display unit 901 receives the remaining amount decrease signal from the external transmission / reception device 10, the display unit 901 displays a remaining amount decrease notification image (for example, the remaining amount “low”). Note that the display unit 901 may emit a warning sound together with the remaining amount decrease signal.

<Operation>
Next, the operation by the ink management system will be described.

  When the ink cartridge 92 is housed in the cartridge holder 91, various signals (transmission signal, reply signal) are exchanged between the external transmission / reception device 10 and the wireless transmission device 20, and the external transmission / reception device 10 The control part 11 calculates | requires a communication distance regularly. Further, the control unit 11 obtains the internal volume of the ink stored in the ink cartridge 92 based on the obtained communication distance. Next, the control unit 11 writes the ID information and ink information detected by the information detection unit 109 and the obtained ink content in the management information, and periodically outputs the management information to the display unit 901. Management information displayed on the display unit 901 is periodically updated.

  If the control unit 11 of the external transmission / reception device 10 determines that the obtained ink content is equal to or less than the specified amount, the control unit 11 outputs a remaining amount decrease signal. Therefore, “remaining amount“ low ”” is displayed on the display unit 901. Thereby, replacement of the ink cartridge can be urged.

<Effect>
As described above, the type and content of ink stored in the ink cartridge can be managed simultaneously.

  In addition, the floating member 302 provided with a wireless transmission device (for example, a wireless tag) can be manufactured with a size of about several millimeters square, and thus can be mounted inside a small ink cartridge.

  In addition, in each of the application examples of the present embodiment described above, naturally, the first modification and the second modification of the present embodiment are also applicable.

  As described above, the present invention can detect the position of the wireless transmission device, so that the present invention can be applied to a container management system for managing the content of contents stored in a predetermined storage container, or a paper feed tray. This is useful as a paper management system for managing the stored printer paper.

The figure for demonstrating the whole structure and reply signal of the transmission / reception system by embodiment of this invention. The graph which shows the relationship between a signal, a reception level, and communication distance. (A) The graph which shows the relationship between communication S / N and communication distance. (B) A graph showing the relationship between error rate and communication S / N. (C) A graph showing the relationship between the number of error corrections and the communication distance. The block diagram which shows the internal structure of the external transmission / reception apparatus shown in FIG. The block diagram which shows the internal structure of the transmission signal supply part shown in FIG. The block diagram which shows the internal structure of the decoding part and signal state detection part which were shown in FIG. The block diagram which shows the internal structure of the wireless transmission apparatus shown in FIG. The figure which shows an example of a level information corresponding | compatible table. The block diagram which shows the internal structure of the decoding part shown in FIG. The block diagram which shows the internal structure of the reply signal supply part shown in FIG. The wave form diagram for demonstrating the mode of the change of each signal by a load modulation system. The block diagram for demonstrating the modification of the control part shown in FIG. Waveform diagram for explaining how each signal changes due to another load modulation method The wave form diagram for demonstrating the mode of a change of each signal in the transmission / reception system by the modification 1 of embodiment of this invention The wave form diagram which shows the mode of the change of each signal in the transmission / reception system by the modification 2 of embodiment of this invention. The figure which shows the structure of the container management system by the application example 1 of embodiment of this invention. The figure which shows the example of installation of the wireless type transmission apparatus in the floating member shown in FIG. The figure for demonstrating the case where the liquid in the storage container shown in FIG. 16 decreases. The figure which shows the example of installation of the wireless type transmission apparatus in the floating member shown in FIG. The figure which shows the modification 1 of the storage container shown in FIG. The figure which shows the modification 2 of the storage container shown in FIG. The figure for demonstrating the case where the liquid in the storage container shown in FIG. 21 decreases. The figure which shows the structure of the fuel cell system by the application example 2 of embodiment of this invention. The figure which shows the structure of the infusion management system by the application example 3 of embodiment of this invention. FIG. FIG. 27 is a schematic cross-sectional view of the paper feed tray shown in FIG. 26. FIG. 10 is a schematic cross-sectional view for explaining a configuration of a paper management system according to an application example 4 of the embodiment of the present invention. (A) External view of printer. (B) External view of cartridge holder. The figure for demonstrating the structure of the ink management system by the application example 5 of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 External transmission / reception apparatus 20 Wireless transmission apparatus 11, 25 Control part 12 Transmission signal supply part 13, 22 Transmission / reception part 14, 24 Decoding part 15 Signal state detection part 21 Storage part 23 Voltage generation part 26 Reply signal supply part 27 Modulation degree Selection unit 28 Level setting unit 101, 204 Encoding processing unit 102, 205 Error correction code addition unit 103 Transmission data generation unit 104, 207 Modulation circuit 105 Reception amplification circuit 106, 201 Demodulation circuit 107, 202 Error correction circuit 108, 203 Decoding Processing section 109 information detection section 110 amplification degree calculation section 111 error location counting circuit 206 transmission data generation section 30, 30A, 30B container 301, 301A container main body 302 floating member 302A partition member 40 display device 50 fuel cell unit 500 power generation section 501 Fuel supply pump 502 DMFC power generation cell 503 Voltage conversion circuit 60 Electronic device 601 Control microcomputer 602 Display unit 71 Infusion pack 72 Infusion solution stand 80, 90 Printer 81 Paper feed tray 82 Printer main body 800 Tray storage unit 801 Tray main body 802 Paper feed plate 803 Energizing members 804, 901 Display unit 91 Cartridge holder 92 Ink cartridge

Claims (24)

A transmission / reception system in which an external transmission / reception device that transmits a carrier wave and modulates a carrier wave based on transmission data communicates with a wireless transmission device that performs load modulation on the carrier wave from the external transmission / reception device. There,
The wireless transmission device includes:
A first transmission / reception unit that receives a carrier wave from the external transmission / reception device, and can change a modulation degree of the carrier wave during load modulation;
A first controller that sequentially outputs a plurality of reply information including distance information indicating different predicted distances when the transmission signal is received by the first transceiver;
When receiving the return information from the first control unit, a return signal is generated based on the return information, and the generated return signal is supplied.
A level setting unit that sets a modulation degree in the first transmission / reception unit to a modulation degree corresponding to distance information included in the reply information output to the reply signal supply unit;
The first transmitting / receiving unit sequentially transmits a plurality of return signals having different amplitude levels by load-modulating a carrier wave from the external transmission / reception device based on a return signal from the return signal supply unit,
The external transmission / reception device is:
A transmission signal supply unit for supplying a transmission signal by supplying a carrier wave and modulating the carrier wave based on transmission data;
A second transmission / reception unit that transmits a carrier wave from the transmission signal supply unit while receiving a return signal transmitted by load modulation in the external transmission / reception device;
A signal state detection unit for detecting a reception state of a reply signal received by the second transmission / reception unit;
An information detection unit for detecting distance information from the reply signal received by the second transmission / reception unit;
The distance information detected by the information detection unit when each of the amplitude level of the carrier wave transmitted by the second transmission / reception unit and the reception state of the return signal detected by the signal state detection unit satisfies a predetermined condition. A second transmission / reception system comprising: a second control unit that obtains a predicted distance indicated by as a communication distance between the external transmission / reception device and the wireless transmission device. In claim 1,
The level setting unit has a modulation degree in the first transmission / reception unit, the communication distance is a predicted distance indicated by distance information included in reply information output to the reply signal supply unit, and the external The amplitude level of the carrier wave transmitted from the transmission / reception device and the reception level of the return signal corresponding to the return information in the external transmission / reception device are each set to a modulation degree when the predetermined condition is satisfied. Sending and receiving system In claim 2,
The level setting unit has a correspondence relationship between a communication distance and a modulation degree when each of an amplitude level of a carrier wave from the external transmission / reception device and a reception state of a return signal in the external transmission / reception device satisfies a predetermined condition. A level information correspondence table, and selects a modulation degree corresponding to the predicted distance indicated by the distance information included in the reply information output to the reply signal supply unit from the level information correspondence table, and A transmission / reception system, wherein a modulation degree in a transmission / reception unit is set to the selected modulation degree. In any one of Claims 1-3,
The external transmission / reception device is:
A reception amplification unit that amplifies the amplitude level of the reply signal received by the second transmission / reception unit to a predetermined level;
The signal state detection unit measures the amplification degree of the reply signal by the reception amplification unit,
The second control unit determines that the reception state of the return signal satisfies a predetermined condition when the amplification level of the return signal measured by the signal state detection unit is a predetermined amplification level. Sending and receiving system. In any one of Claims 1-3,
The signal state detection unit counts the number of error locations occurring in the reply signal received by the second transmission / reception unit,
The second control unit determines that the reception state of the return signal satisfies a predetermined condition when the number of error points counted by the signal state detection unit is a predetermined number. . In any one of Claims 1-3,
The signal state detection unit measures an amplitude level of a reply signal received by the second transmission / reception unit,
The transmission / reception system, wherein the second control unit determines that the reception state of the return signal satisfies a predetermined condition when the amplitude level measured by the signal state detection unit is a predetermined level. In any one of Claims 4-6,
When the reply signal supply unit receives the reply information from the first control unit, the reply signal supply unit generates a reply signal provided with a section corresponding to the reply information and in which the fluctuation of the amplitude level continues, and the generated reply A transmission / reception system characterized by supplying a signal. In claim 1,
A storage container in which the wireless transmission device is provided so as to store the predetermined content and change the communication distance according to an increase or decrease in the content of the content;
The second control unit further determines the content of the predetermined content based on the determined communication distance. In claim 1,
A storage container for storing a predetermined content that is liquid; and
A floating member that floats on the liquid level of the predetermined content stored in the storage container,
The wireless transmission device is provided on the surface of the floating member,
The transmission / reception system, wherein the second control unit further determines an internal volume of a predetermined content stored in the storage container based on the determined communication distance. In claim 1,
A storage container for storing predetermined contents;
A partition member disposed inside the storage container and moving in accordance with an increase or decrease in the content of the predetermined content stored in the storage container;
The wireless transmission device is provided on the partition member,
The transmission / reception system, wherein the second control unit further determines an internal volume of a predetermined content stored in the storage container based on the determined communication distance. In claim 1,
A storage container in which the predetermined contents are stored and the outer shape expands and contracts in accordance with the increase or decrease in the internal volume of the contents;
The wireless transmission device is provided on the surface of the container,
The transmission / reception system, wherein the second control unit further determines an internal volume of a predetermined content stored in the storage container based on the determined communication distance. In any one of claims 8 to 11,
A fuel cell unit including a power generation unit that generates power using liquid fuel;
The storage container stores liquid fuel used by the power generation unit,
The transmission / reception system, wherein the second control unit further determines an internal volume of the liquid fuel stored in the storage container based on the determined communication distance. In claim 1,
An infusion container for containing a predetermined infusion; and
A floating member floating on the liquid surface of the predetermined infusion contained in the infusion container;
A container mounting portion for mounting the infusion container, and
The wireless transmission device is provided on the surface of the floating member,
The second control unit further determines a content volume of a predetermined infusion contained in the infusion container based on the obtained communication distance. In claim 1,
A printer including a paper feed tray for storing printer paper, and a printer main body having a tray storage unit in which the paper feed tray is inserted to store the paper feed tray;
The paper feed tray includes a paper feed tray main body, a paper feed plate disposed inside the paper feed tray main body and on which the printer paper is placed, and a bottom surface of the paper feed tray main body in the insertion direction of the paper feed tray. An urging member that connects one end of the sheet feeding plate and one end of the sheet feeding plate and urges the sheet feeding plate in a direction away from the bottom surface of the tray body,
The wireless transmission device is provided at one end of the sheet feeding plate,
The transmission / reception system, wherein the second control unit further determines the number of sheets of printer paper stored in the paper feed tray based on the determined communication distance. In claim 1,
The printer further includes: an ink cartridge that stores predetermined ink; a floating member that floats on a liquid surface of the ink stored in the ink cartridge; and a printer main body that includes a cartridge holder portion that stores the ink cartridge therein. ,
The wireless transmission device is provided on the surface of the floating member,
The transmission / reception system, wherein the second control unit further obtains an internal volume of ink stored in the ink cartridge based on the obtained communication distance. In any one of claims 8 to 11,
The wireless transmission device includes:
A storage unit that stores content information that is information about the content;
The first control unit further reads the content information stored in the storage unit, writes the read content information to each of the plurality of reply information,
The information detection unit further detects the content information from a reply signal received by the second transmission / reception unit,
The external transmission / reception device is:
A transmission / reception system, further comprising: a display unit configured to display at least one of the content volume obtained by the second control unit and the content information obtained by the information detection unit. A wireless transmission device that performs load modulation on a carrier wave from an external transmission / reception device,
While receiving a carrier wave from the external transmission and reception device, a transmission / reception unit capable of changing the degree of modulation of the carrier wave during load modulation,
When a predetermined modulated carrier wave is received by the transmission / reception unit, a control unit that sequentially outputs a plurality of reply information including distance information indicating different prediction distances;
Upon receipt of the reply information from the control unit, a reply signal is generated based on the reply information, and a reply signal supply unit that supplies the generated reply signal;
A level setting unit that sets a modulation degree in the transmission / reception unit to a modulation degree corresponding to distance information included in the reply information output to the reply signal supply unit;
The transmission / reception unit sequentially transmits a plurality of reply signals having different amplitude levels by load-modulating a carrier wave from the external transmission / reception device based on a reply signal from the reply signal supply unit,
The predicted distance indicated in the distance information included in each of the plurality of reply signals is such that the carrier wave amplitude level from the external transmission / reception device and the reception state of the reply signal in the external transmission / reception device each satisfy a predetermined condition. A wireless transmission device that corresponds to a communication distance when it is satisfied. In claim 17,
The level setting unit has a modulation degree in the transmission / reception unit, the communication distance is a predicted distance indicated in distance information included in reply information output to the reply signal supply unit, and the external transmission / reception device And a modulation level when each of the amplitude level of the carrier wave transmitted from the receiver and the reception state of the return signal corresponding to the return information in the external transmission / reception apparatus satisfies the predetermined condition. Transmission equipment. 19. The level setting unit according to claim 18, wherein the level setting unit includes a communication distance and a modulation degree when each of an amplitude level of a carrier wave from the external transmission / reception device and a reception state of a return signal in the external transmission / reception device satisfies a predetermined condition. A level information correspondence table that indicates the correspondence relationship of, and select a modulation degree corresponding to the predicted distance indicated by the distance information included in the reply information output to the reply signal supply unit from the level information correspondence table, A wireless transmission apparatus, wherein a modulation degree in the transmission / reception unit is set to the selected modulation degree. A transmission / reception method by an external transmission / reception device that transmits a carrier wave, and a wireless transmission device that modulates the carrier wave and can change the modulation degree of the carrier wave during load modulation,
The external transmission / reception apparatus transmits a carrier wave and transmits a transmission signal by modulating the carrier wave based on transmission data; and
A carrier wave receiving step in which the wireless transmission device receives the carrier wave transmitted in the sending step;
When the transmission signal is received in the carrier wave reception step, the wireless transmission device sequentially generates a plurality of return signals including distance information indicating different prediction distances, and the distance information included in the return signal is A generation step of sequentially changing the modulation degree in the wireless transmission device according to the predicted distance to be shown;
A reply step in which the wireless transmission device sequentially transmits a plurality of reply signals having different amplitude levels by load-modulating a carrier wave from the external transmission / reception device based on the reply signal generated in the generating step; ,
A reply signal receiving step in which the external transmission / reception device receives the reply signal transmitted in the reply step;
A signal state detection step of detecting a reception state of the reply signal received in the reply signal reception step;
A detecting step of detecting distance information from the reply signals received in the reply signal receiving step;
The distance information detected in the detection step indicates that each of the amplitude level of the carrier wave transmitted in the transmission step and the reception state of the return signal detected in the signal state detection step satisfies a predetermined condition. A transmission / reception method comprising: acquiring an estimated distance as a communication distance between the external transmission / reception device and the wireless transmission device. In claim 20,
In the generating step, the amplitude of the carrier wave transmitted from the external transmission / reception device, in which the modulation degree in the wireless transmission device is the predicted distance indicated by the distance information included in the return signal. A transmission / reception method characterized by setting a level and a modulation degree when each of the reception states of the reply signal satisfies the predetermined condition in the external transmission / reception apparatus. In claim 20 or claim 21,
An amplifying step of amplifying the amplitude level of the reply signal received in the reply signal receiving step to a predetermined level;
The signal state detection step measures the amplification degree of the return signal in the amplification step,
In the acquisition step, if the amplification degree of the reply signal measured in the signal state detection step is a predetermined amplification degree, it is determined that the reception state of the reply signal satisfies a predetermined condition. . In claim 20 or claim 21,
In the signal state detection step, the number of error points occurring in the reply signal received in the reply signal reception step is counted,
In the acquisition step, when the number of error locations counted in the signal state detection step is a predetermined number, it is determined that the reception state of the reply signal satisfies a predetermined condition. In claim 20 or claim 21,
In the signal state detection step, the amplitude level of the reply signal received in the reply signal reception step is measured,
In the acquisition step, when the amplitude level of the return signal measured in the signal state detection step is a predetermined level, it is determined that the reception state of the return signal satisfies a predetermined condition.

Images