JP2006157593A - Rfid communication system and wireless communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify the configuration of a reader/writer for an RFID tag. <P>SOLUTION: A wireless communication device (2) is connected to a host device (1) for outputting instruction information of RFID recording media (3A, 3B) in an RFID communication system. A plurality of antenna mechanisms for transmitting/receiving transmitting signals to the RFID recording media and received signals from the RFID recording media are provided to the wireless communication device (2) for each of communication specifications of the RFID recording media. The wireless communication device is provided with a control mechanism having a signal processing means which generates a transmitting signal and analyzes a received signal on the basis of the communication specifications shown by the instruction information, and antenna switching means 30, 31 for selecting an antenna mechanism to transmit a transmitting signal and an antenna mechanism to receive a received signal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a communication system using RFID (Radio frequency identification) technology, which is rapidly spreading at present, and a wireless communication apparatus that performs data writing and reading with respect to an RFID recording medium in the system.

  2. Description of the Related Art Conventionally, communication systems using RFID technology, for example, as described in Non-Patent Document 1 to be described later, are used for RFID recording media such as tags and cards having ICs that store information and can read and write at high speed. It is known to read and write information by a reader / writer which is a communication device. A major feature of RFID technology is that it uses non-contact communication between a reader / writer and a recording medium, that is, communication using an electromagnetic field at a short distance across a space. As a general principle using an electromagnetic field, For example, there is electromagnetic induction.

  A passive type RFID recording medium to which the principle of electromagnetic induction is applied operates an IC using a current induced by a radio wave from a reader / writer, and transmits information to the reader / writer with this radio wave. . The reader / writer side receives information from the recording medium by receiving the radio wave transmitted by itself, thereby enabling bidirectional communication.

  FIG. 10 is a configuration example of a conventional RFID communication system using an RFID tag attached to an article or the like as an RFID recording medium. The illustrated system includes a host computer 100, a reader / writer 200, and an RFID tag 300. The RFID tag 300 receives the radio wave transmitted from the reader / writer 200 by the antenna module 301, and the main control unit 302 decodes the contents and writes or reads data to or from the tag internal memory 303. In the case of data reading, the main control unit 302 performs predetermined modulation processing on the data read from the tag internal memory 303 and transmits the data to the reader / writer 200.

  The reader / writer 200 writes / reads data to / from the RFID tag 300 in accordance with an instruction from the host computer 100 operated by an application program corresponding to the communication specification of the RFID tag 300. The reader / writer 200 is roughly divided into a controller 210 and an antenna unit 220 as shown in FIG.

  The controller 210 encodes an instruction command as instruction information from the host computer 100 using the encoder 214 by the command interpreter unit 211 and passes it to the tag driver 213. When the instruction is data writing, a value to be written is temporarily stored in the memory 212. The tag driver 213 converts an instruction from the host computer 100 into a radio wave format and passes it to the antenna module 221. The antenna module 221 transmits the radio wave to the RFID tag 300 as a transmission signal.

  The tag driver 213 analyzes an analog signal as a radio wave received from the RFID tag 300 via the antenna module 221, converts the content into a digital signal, and passes the digital signal to the command interpreter unit 211. The command interpreter unit 211 decodes the received digital signal by the decoder 215 and supplies it to the host computer 100 as data read from the tag.

  FIG. 11 schematically shows a configuration related to communication between the RFID driver 300 and the tag driver 213 and the antenna module 221 shown in FIG. The tag driver 213 inputs a digital signal formed by performing predetermined modulation processing using data to be transmitted to the D / A converter 214, thereby generating an analog baseband signal. In addition, the frequency of the standing wave analog signal output from the oscillator 217 is converted into the communication frequency of the RFID tag 300 by the multiplier 218 to form a carrier wave signal. Then, an analog modulation signal is generated by superimposing the baseband signal on the carrier wave signal, which is amplified by the transmission amplifier 219 a and passed to the antenna module 221.

  The antenna module 221 outputs the passed signal from the coil L1 as a transmission signal. In addition, a radio wave as a reception signal from the RFID tag 300 having the coil L3 as the antenna module 301 is received by the coil L2, and data is demodulated from the digital signal formed through the reception amplifier 219b and the A / D converter 216b. Is done.

  By the way, as a modulation format in the reader / writer 200 and the RFID tag 300, basically, amplitude modulation (AM: Amplitude Modulation, ASK: Amplitude Shift Keying) for reflecting data to be transmitted on the amplitude component of the carrier, and the frequency of the carrier Either frequency modulation (FM: Frequency Modulation, FSK: Frequency Shift Keying) reflected on the component or phase modulation (PM: Phase Modulation, PSK: Phase Shift Keying) reflected on the phase component of the carrier wave is applied. As the communication frequency, 135 KHz (long wave band), 6.78 MHz, 13.56 MHz (short wave band), 915 MHz (ultra short wave band), 2.45 GHz (microwave band), or the like is used.

  Conventionally, for example, a system as shown in FIG. 12 has been proposed in order to deal with such a wide variety of communication specifications. In the illustrated system, the reader / writer 200 includes a tag driver 213A and an antenna for communication with the RFID tag 300A in order to enable communication with two types of RFID tags 300A and 300B having different communication specifications. The module 221A includes a tag driver 213B and an antenna module 221B for communication with the other RFID tag 300B. Each tag driver (213) and each antenna module (221) have the same configuration as that shown in FIG.

Regarding a system as shown in FIG. 12, for example, there is a method described in Patent Document 1 described later. The reader / writer in Patent Document 1 includes three antenna units that transmit and receive radio waves in three types of frequency bands, and three modem units that modulate / demodulate radio waves in each frequency band. The access request command is output to the terminal, the frequency band and the protocol are determined based on the tag type notified from the tag in response to the command, and the antenna unit and the modem unit corresponding to the determined content communicate with the tag. .
JP 2001-291079 A Hiroshi Isobe, “Book of Contactless IC Card”, Nikkan Kogyo Shimbun, October 30, 2003

  However, if one reader / writer is made to correspond to a plurality of frequency bands, the reader / writer 200 shown in FIG. 12 has N types of antenna modules (221) as in the reader / writer described in Patent Document 1. It is necessary to provide N types of tag drivers (213) for generating / analyzing radio waves transmitted / received. This means that one tag driver having the configuration shown in FIG. 11 is mounted on one reader / writer 200. This increases the size of the reader / writer housing due to an increase in the number of tag drivers. In particular, in the case where the reader / writer is a portable type, inconvenience arises for the user carrying the reader / writer. In addition, there is a problem that the product price increases as the number of mounted tag drivers increases.

  The present invention has been made in view of the above problems, and an object thereof is to provide a technique for simplifying a reader / writer that can cope with a plurality of communication specifications.

  An RFID communication system according to the present invention includes an RFID recording medium having wireless communication means and data storage means based on a predetermined communication specification, and a host that outputs instruction information including a data writing instruction or a data reading instruction for the RFID recording medium Apparatus and a wireless communication device for writing data to or reading data from the RFID recording medium based on instruction information output from the host device, the wireless communication device having different communication specifications for the RFID recording medium And a plurality of antenna mechanisms for transmitting / receiving a transmission signal to / from the RFID recording medium and a reception signal from the RFID recording medium, and generation of the transmission signal and analysis of the reception signal for communication specifications of the RFID recording medium And a signal processing means for executing the transmission signal, and an antenna to which the transmission signal is to be transmitted And a control mechanism having an antenna switching unit for selecting an antenna mechanism to receive the said reception signal and Kamao.

  The wireless communication device according to the present invention is an instruction output from a host device that outputs instruction information including a data write instruction or a data read instruction to an RFID recording medium having a wireless communication means and a data storage means based on a predetermined communication specification. A wireless communication apparatus that performs data writing or data reading on the RFID recording medium based on information, corresponds to communication specifications of the RFID recording medium different from each other, and transmits a transmission signal to the RFID recording medium and the RFID recording A plurality of antenna mechanisms for transmitting and receiving signals received from a medium; signal processing means for generating the transmission signal and analyzing the received signal based on communication specifications of the RFID recording medium; and an antenna to transmit the transmission signal An antenna switch for selecting a mechanism and an antenna mechanism to receive the received signal. And a control mechanism having a means.

  According to the present invention, in a wireless communication apparatus that performs data writing and reading with respect to an RFID recording medium, a transmission mechanism and a reception signal transmitted and received by a plurality of antenna mechanisms are collectively generated or analyzed by a control mechanism. It is not necessary to mount the same number of mechanisms for modulating or demodulating signals as the number of antennas. Thereby, the structure of a radio | wireless communication apparatus can be simplified.

  In the present invention, in order to simplify the configuration of a reader / writer that can cope with a wide variety of communication specifications of an RFID recording medium, components that have been realized by hardware in the reader / writer are partially replaced with software. It is. As a specific example, in the present invention, the function of an oscillator that generates a carrier wave based on an analog signal is delegated to a digital signal processor. That is, the digital signal processor simulates a standing wave analog signal with a digital signal, thereby generating a pseudo carrier wave. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Embodiment]
FIG. 1 is a block diagram showing a configuration of an embodiment of an RFID communication system according to the present invention. The system of this embodiment is a system that uses a conventionally known RFID tag attached to an article for sales management, inventory management, etc. as an RFID recording medium. As shown in FIG. Two types of RFID tags 3A and 3B, a host computer 1 that operates according to an application program for instructing data writing to and reading from these RFID tags (3), and an RFID tag according to instructions from the host computer 1 Specification for storing a reader / writer 2 which is a wireless communication device for writing and reading data with respect to (3), and a wireless control program 8 described later in which a wireless control procedure between the RFID tag (3) and the reader / writer 2 is described. And a server 4.

  The RFID tag 3A and the RFID tag 3B have different communication specifications with the reader / writer 200 such as a communication frequency and a modulation format, but main components are the same as those of the conventional RFID tag described with reference to FIG. It is the same. That is, the RFID tag 3A demodulates and decodes the antenna module 5A that transmits / receives electromagnetic waves to / from the reader / writer 2, the in-tag memory 6A that temporarily stores data, and the signal received by the antenna module 5A. The main control unit 7A interprets and executes an instruction command from the writer.

  Further, the RFID tag 3B includes an antenna module 5B, an in-tag memory 6B, and a main control unit 7B that perform the same functions as the antenna module 5A, the in-tag memory 6A, and the main control unit 7A, according to the communication specifications. Note that the example shown in FIG. 1 has a configuration in which two types of communication specifications exist, but the communication specification of a system to which the present invention can be applied is not limited to two types, and may be three or more types.

  The specification server 4 is a computer device that is communicably connected to the reader / writer 2 and is a radio control program that describes routines to be described later performed by the reader / writer 2 for data writing and reading for each communication specification of the RFID tag (3). 8 is held. The wireless control program 8 corresponds to communication information held by the server device in the present invention. Specifically, the radio control program 8 of the present embodiment includes a digital modulation format (ASK, FSK modulation, PSK modulation, etc.) and a communication frequency (135 KHz (long wave band), 6.78 MHz, 13.56 MHz (short wave band), 915 MHz. (Ultra-high frequency band, etc.)) is a program in which a communication specification and a procedure for data writing and reading are associated with each other. As described above, the configuration in which the necessary radio control program 8 is downloaded from the external specification server 4 can flexibly cope with the communication specification of the RFID tag (3).

  The reader / writer 2 includes a controller 9 and an antenna unit 10. The antenna unit 10 includes an antenna module 10A and an antenna module 10B similar to the antenna module of the conventional antenna unit described with reference to FIG. 11, and each antenna module 10A and 10B transmits an analog signal to the air as an electromagnetic wave. And a receiving coil (12) for receiving an electromagnetic wave in the air and taking it in as an analog signal.

  The antenna modules 10 </ b> A and 10 </ b> B are components corresponding to a plurality of antenna mechanisms included in the wireless communication apparatus according to the present invention, and are provided in a quantity corresponding to the number of communication specifications handled by the reader / writer 2. In this embodiment, two types of antenna modules corresponding to two types of communication specifications are provided. In this embodiment, the so-called full-duplex method is adopted in which the antenna coil is separated for transmission and reception, but instead of this, a half-duplex method in which transmission / reception is performed by a single antenna coil is adopted. It may be a configuration.

  The controller 9 is a component corresponding to the control mechanism of the wireless communication apparatus according to the present invention, and includes a command interpreter 15, a tag driver interpreter 17, and a specification download unit 13. When communicating with the RFID tag (3), the specification download unit 13 requests the specification server 4 to download a radio control program 8 described later, and receives and stores the program. As described above, the wireless control program 8 is a program in which a routine for executing writing to a tag and a routine for executing reading are described for each communication specification, and each routine includes a tag driver. The interpreter 17 interprets and executes the instructions one by one.

  The command interpreter 15 receives a command serving as instruction information from the host computer 1, and determines a read instruction or a write instruction for the RFID tag (3) from the command. In the case of a write instruction, data to be written is received from the host computer 1 and the tag driver interpreter 17 is instructed to write the data. In the case of a read instruction, the tag driver interpreter 17 is instructed to read data from the RFID tag (3), and a process of receiving the read data and returning it to the host computer 1 is performed.

  The tag driver interpreter 17 executes a routine for writing / reading based on the radio control program 8 acquired by the specification download unit 13. In the routine corresponding to the write instruction, the data to be transmitted passed from the command interpreter 15 is subjected to designated modulation and passed to the transmission coil (11) of the communication specification. Further, in the routine corresponding to the read instruction, in addition to the routine similar to the routine at the time of the write instruction, the analog signal received from the reception coil (12) of the communication specification is demodulated, and the processing result is displayed as a command interpreter. Return to 15.

  FIG. 2 shows the configuration of the tag driver interpreter 17 that executes the above routine. The program memory 22 stores the radio control program 8 acquired by the specification download unit 13. The data memory 23 temporarily stores write data to the RFID tag (3) and read data from the RFID tag (3).

  As the digital signal processor 21, a commercially available digital signal processor can be used as the one that performs the function of the digital signal calculation unit of the wireless communication apparatus in the present invention. In this embodiment, the communication of the RFID tag (3) is used. The one having a processing speed capable of dealing with the communication frequency specified in the specification is adopted. For example, when the highest communication frequency of the RFID tag (3) to be handled is 13.56 MHz, a digital signal processor that operates at a frequency equal to or higher than this frequency is used.

  The digital signal processor 21 executes each routine for writing / reading data to / from the RFID tag (3) according to the downloaded radio control program 8, and in each routine, for a transmission signal to the RFID tag (3). A digitally modulated signal is generated. The procedure for generating the digital modulation signal will be described in detail later.

  The D / A converter 24 receives the digital modulation signal output from the digital signal processor 21 and converts it into an analog signal. The transmission amplifier 28 amplifies the converted analog signal to a predetermined transmission output level and passes it to the output antenna switching unit 30 as a transmission signal. The reception amplifier 29 amplifies the signal strength of the reception signal passed from the input antenna switching unit 31. The A / D converter 25 receives and samples the amplified analog signal, converts it to a digital signal, and passes it to the digital signal processor 21. The D / A converter 24, the transmission amplifier 28, the reception amplifier 29, and the A / D converter 25 are components that perform the function of the signal conversion unit of the wireless communication apparatus according to the present invention.

  The output antenna switching unit 30 selects an antenna module that should transmit a transmission signal from the antenna module 10A and the antenna module 10B. The input antenna switching unit 31 selects an antenna module that should receive a reception signal from the RFID tag (3).

  Hereinafter, the operation procedure of this embodiment will be described. Here, as an example, a procedure in which the reader / writer 2 performs data writing or reading on the RFID tag 3A shown in FIG. 1 will be described. FIG. 3 is a flowchart showing an operation procedure of the command interpreter 15 in the reader / writer 2.

  When the command interpreter 15 receives an instruction command including the communication specification of the RFID tag 3A from the host computer 1 (step S1), the command interpreter 15 determines whether the instruction content is data writing or data reading (step S1). S2). As a result of the determination, if the instruction from the host computer 1 is data writing, the data to be written is received from the host computer 1 (step S3), and corresponds to the communication specification of the RFID tag 3A in the routine for data writing. The tag driver interpreter 17 is instructed to execute the routine to execute (step S4). If the instruction from the host computer 1 is data reading, the tag driver interpreter 17 is instructed to execute a routine corresponding to the communication specification of the RFID tag 3A among the data reading routines (step S5).

  As a method for the reader / writer 2 to recognize the communication specification of the RFID tag (3), for example, information related to the communication specification of the RFID tag (3) is described in the instruction information output from the host computer 1, or The reader / writer 2 holds an information table in which the RFID tag (3) and its communication specifications are associated, and information for identifying the target RFID tag (3) is read from the host computer 1 at the time of data writing / reading. The method of outputting may be used.

  The operation procedure of the tag driver interpreter 17 that has received the above instruction from the command interpreter 15 will be described. FIG. 4 is a flowchart showing an operation procedure in the data write instruction. In the following description, for convenience, the radio control program 8 describing a routine for writing data to the RFID tag 3A is referred to as “label 1”, and the radio control program 8 for reading data is referred to as “label 2”. Called. Here, “label 1” and “label 2” are programs corresponding to the communication specifications of the RFID tag 3A.

  The digital signal processor 21 of the tag driver interpreter 17 instructs the specification download unit 13 to download the wireless control program 8 corresponding to the routine for writing data to the RFID tag 3A from the specification server 4, and the downloaded wireless control The program 8, that is, “label 1” is stored in the program memory 22 (step S10). Then, according to “label 1”, the following processing for outputting a transmission signal is executed.

  The digital signal processor 21 generates a digital modulation signal from the data signal including the write command and the write data supplied from the command interpreter 15 (step S11). The procedure for generating the digital modulation signal will be described in detail later. Further, the output antenna switching unit 30 is instructed to use the antenna module 10A corresponding to the communication frequency of the RFID tag 3A as an antenna module for outputting a transmission signal (step S12).

  The D / A converter 24 converts the digital modulation signal generated by the digital signal processor 21 from a digital signal to an analog signal (step S13), and amplifies the analog signal to a predetermined transmission output level by the transmission amplifier 28 (step S13). S14). The amplified analog signal is output from the output antenna switching unit 30 to the air as a transmission signal via the transmission coil 11A of the antenna module 10A (step S15).

  Next, the data reading process in the tag driver interpreter 17 will be described with reference to the flowchart shown in FIG. The digital signal processor 21 of the tag driver interpreter 17 instructs the specification download unit 13 to download the wireless control program 8 corresponding to the routine for reading from the specification server 4 to the RFID tag 3A, and the downloaded wireless control program 8 That is, “label 2” is stored in the program memory 22 (step S20). Then, according to “Label 2”, the following processing for outputting a transmission signal is executed.

  The output procedure of the transmission signal from the reader / writer 2 to the RFID tag 3A at the time of data reading is performed by replacing the data signal in the procedure described with reference to FIG. 4 from the write command and the write data to the read command. The description is omitted here (steps S21 to S25).

  The digital signal processor 21 instructs the input antenna switching unit 31 to select the antenna module 10A corresponding to the communication frequency of the RFID tag 3A as a receiving antenna in order to prepare for reception of read data from the RFID tag 3A. (Step S26). Thereafter, when a signal from the RFID tag 3A is received by the receiving coil 12A of the antenna module 10A, the receiving amplifier 29 amplifies the received signal to a predetermined intensity level (step S27), and the amplified analog signal is converted to A / A. The D converter 25 converts it into a digital signal and passes it to the digital signal processor 21 (step S28).

  The digital signal processor 21 demodulates the received digital signal in accordance with the communication specification of the RFID tag 3A, and passes the read data extracted by the demodulation to the host computer 1 as a processing result in response to a read instruction from the host computer 1. The process ends (step S29).

  Here, with reference to the explanatory diagram of FIG. 6, the procedure for generating the digital modulation signal in steps S11 and S21 will be described. The digital signal processor 21 performs conventionally known baseband modulation in order to convert “1011”, which is a data signal indicating the content of transmission to the RFID tag 3A, into a baseband signal used for modulation. Specifically, a digital signal representing a subcarrier having a frequency lower than that of the original carrier is generated by simulation by the digital signal processor 21 (not shown), and a digital signal “1011” is superimposed on the digital signal of the subcarrier. . As a result, a waveform as shown as a result of the baseband modulation in FIG. 6 is obtained.

  The digital signal processor 21 generates a digital signal representing a standing wave having the same frequency as the communication frequency of the RFID tag 3A, that is, a digital signal representing a carrier wave by simulation. This processing refers to generating a carrier wave in a pseudo manner using a digital signal. The digital signal processor 21 performs pseudo digital modulation by superimposing the above-described baseband signal on the generated digital signal of the carrier wave, thereby generating a digital modulation signal. The digital modulation signal output from the digital signal processor 21 is shaped as an analog waveform by the D / A converter 24.

  The waveform of the digital modulation signal and the waveform after baseband modulation shown in FIG. 6 are both waveforms obtained by amplitude modulation (ASK). However, the modulation format is not limited to amplitude modulation, and the RFID tag (3) Frequency modulation (FSK) or phase modulation (PSK) is executed according to the communication specifications. In the demodulation process of the received signal, the demodulation process corresponding to the modulation format applied to the above process is performed.

  According to the embodiment described above, the reader / writer 2 generates and analyzes the transmission signal and the reception signal transmitted and received by the plurality of antenna modules 10A and 10B by the tag driver interpreter 17 in a lump. Compared with the conventional method in which the tag driver is mounted on the hardware, the number of hardware used can be greatly reduced. As a result, the size of the reader / writer can be reduced, and the product cost can be reduced.

[Other Embodiments]
In the system of the above-described embodiment, the digital signal processor 21 mounted on the tag driver interpreter 17 has a processing speed that can cope with the communication frequency of the RFID tag (3). It is also possible to use a digital signal processor whose frequency is lower than the communication frequency of the tag. A configuration for this is shown in FIG.

  As shown in FIG. 7, in addition to the configuration shown in FIG. 2, the tag driver interpreter 17 ′ of the present embodiment includes a carrier wave D / A converter 32 that converts an output signal from the digital signal processor 21 into an analog signal, A multiplier 26 that converts the frequency of the analog signal from the converter 32 to an integral multiple, and a frequency converter 27 that performs analog modulation processing described later using the output from the multiplier 26 and the output from the D / A converter 24 are provided. .

  FIG. 8 is a flowchart showing an operation procedure of data writing processing in the tag driver interpreter 17 ′. Here, the radio control program 8 describing a routine for writing data is referred to as “label 1 ′”. The procedure shown in FIG. 8 will be described using the explanatory diagram of FIG. The tag driver interpreter 17 ′ downloads “label 1 ′” from the specification server 4 as the wireless control program 8 for writing data to the RFID tag 3 </ b> A (step S <b> 30), and performs the following processing according to this “label 1 ′”. Execute.

  The digital signal processor 21 generates a first digital signal representing a standing wave and a second digital signal based on the data signal “1011” (step S31). As a result, a waveform as shown in FIG. 9 is obtained. The second digital signal is generated by the same process as the baseband modulation process described with reference to FIG. The first digital signal is generated by the digital signal processor 21 simulating a standing wave. It is desirable that the frequency of the standing wave is the same or an integer multiple of the frequency of the subcarrier for the other second digital signal.

  The digital signal processor 21 instructs the output antenna switching unit 30 to select an output antenna corresponding to the communication frequency, similarly to the procedure in step S14 of FIG. 4 (step S32).

  The D / A converter 24 converts the second digital signal output from the digital signal processor 21 into a second analog signal (step S33). As a result, an analog waveform as shown in FIG. 9 as the processing result of the D / A converter 24 is obtained. The D / A converter 24 inputs the converted second analog signal to the frequency converter 27.

  On the other hand, the first digital signal output from the digital signal processor 21 is converted into a first analog signal by the carrier wave D / A converter 32 (step S33) and input to the multiplier 26. The multiplier 26 converts the input first analog signal into the same frequency as the communication frequency of the RFID tag 3A by performing a process of multiplying the frequency (step S34). Thereby, the first analog signal is converted into a carrier wave for the transmission signal.

  The frequency converter 27 performs analog modulation by superimposing the second analog signal from the D / A converter 24 on the first analog signal as a carrier wave output from the multiplier 26 and generates an analog modulation signal. (Step S35). As a result, a waveform as shown in FIG. 9 as an analog modulation signal is obtained. In the example shown in FIG. 9, amplitude modulation (ASK, AM) is applied as the modulation format. However, the modulation format corresponding to the communication specification of the RFID tag (3) is not limited to the amplitude modulation as in this example. You can do it.

  The transmission amplifier 28 amplifies the analog modulation signal output from the frequency converter 27 to a strength required for the transmission signal (step S36). The amplified transmission signal is output from the output antenna switching unit 30 to the air via the transmission coil 11A (step S37).

  Further, the output procedure of the transmission signal in the data reading process can be implemented by applying a read command to the RFID tag 3A as the data signal used in step S31 of FIG. 8, and the receiving procedure of the read data is shown in FIG. It can implement by the procedure similar to step S26-step S29.

  According to the embodiment described above, even when a digital signal processor 21 having a processing speed lower than the communication frequency of the RFID tag (3) is used, the same effect as the system shown in FIG. Can play.

  In each of the embodiments described above, the reader / writer 2 is configured to download the wireless control program 8 from the specification server 4. Instead, the necessary wireless control program 8 is installed in the controller 9 of the reader / writer 2 in advance. It may be configured to keep.

  In each of the above embodiments, the RFID tag is used as the RFID recording medium in the present invention. However, the mode of the medium is not limited to the tag, and a so-called non-contact IC in which an IC chip for RFID technology is mounted on a resin card. The card may be applied to an RFID recording medium.

It is a block diagram which shows the structure of embodiment of this invention. It is a block diagram which shows the structure of the reader / writer in embodiment. It is a flowchart which shows the operation | movement procedure of the command interpreter in embodiment. It is a flowchart which shows the data writing procedure of embodiment. It is a flowchart which shows the data read-out procedure of embodiment. It is explanatory drawing of the production | generation procedure of the digital modulation signal in embodiment. It is a block diagram which shows the structure of the reader / writer in other embodiment. It is a flowchart which shows the data writing procedure of other embodiment. It is explanatory drawing of the production | generation procedure of the analog modulation signal in embodiment. It is a block diagram which shows the structure of the conventional RFID communication system. It is a block diagram which shows the functional structure in the conventional system. It is a block diagram which shows the other structure of the conventional RFID communication system.

Explanation of symbols

1: host computer, 2: reader / writer, 3: RFID tag, 4: specification server, 5: antenna module, 6: memory in tag, 7: main control unit, 8: wireless control program, 9: controller, 10: antenna Unit: 11: Coil for transmission, 12: Coil for reception, 13: Specification download section, 15: Command interpreter, 17: Tag driver interpreter, 21: Digital signal processor, 22: Program memory, 23: Data memory, 24: D / A converter, 25: A / D converter, 26: multiplier, 27: frequency converter, 28: transmission amplifier, 29: reception amplifier, 30: output antenna switching section, 31: input antenna switching section, 32: D / A converter for carrier wave

Claims (11)

An RFID recording medium having wireless communication means and data storage means based on a predetermined communication specification, a host apparatus that outputs instruction information including a data write instruction or a data read instruction to the RFID recording medium, and output from the host apparatus A wireless communication device for writing data to or reading data from the RFID recording medium based on the instruction information
The wireless communication device
A plurality of antenna mechanisms corresponding to communication specifications of the RFID recording media different from each other and transmitting and receiving a transmission signal to the RFID recording medium and a reception signal from the RFID recording medium;
A signal processing unit that executes generation of the transmission signal and analysis of the reception signal based on communication specifications of the RFID recording medium, an antenna mechanism that should transmit the transmission signal, and an antenna mechanism that should receive the reception signal are selected. An RFID communication system comprising: a control mechanism having an antenna switching means. The control mechanism as the signal processing means,
A digital signal calculation unit that generates a digital modulation signal formed by superimposing a baseband signal representing the transmission data on a digital signal representing a carrier wave of a communication frequency in the communication specification;
The RFID communication system according to claim 1, further comprising: a signal conversion unit that converts the digital modulation signal into an analog signal and amplifies and outputs the analog signal as the transmission signal. The control mechanism as the signal processing means,
A first digital signal representing a standing wave of a predetermined frequency, and a digital signal computing unit for generating a second digital signal formed by superimposing a baseband signal representing the transmission data on the digital signal representing a standing wave of a predetermined frequency;
The first digital signal and the second digital signal are converted into a first analog signal and a second analog signal, the frequency of the first analog signal is converted into a communication frequency of the communication specification, and the communication A signal conversion unit that generates an analog modulation signal formed by superimposing the second analog signal on the first analog signal converted into a frequency, amplifies the analog modulation signal as the transmission signal, and outputs the amplified signal. The RFID communication system according to claim 1. The signal conversion unit converts an analog signal as the reception signal into a digital signal,
4. The RFID communication system according to claim 2, wherein the digital signal calculation unit extracts a baseband signal from the digital signal converted by the signal conversion unit based on the communication specification. A server device that is communicably connected to the wireless communication device and holds communication information related to communication specifications of the RFID recording medium in association with the RFID recording medium;
5. The RFID communication according to claim 1, wherein the wireless communication device acquires communication information corresponding to the RFID recording medium from the server device at the time of data writing and data reading. system. Data for the RFID recording medium based on instruction information output from a host device that outputs instruction information including a data writing instruction or a data reading instruction for an RFID recording medium having wireless communication means and data storage means based on a predetermined communication specification A wireless communication device for writing or reading data,
A plurality of antenna mechanisms corresponding to communication specifications of the RFID recording media different from each other and transmitting and receiving a transmission signal to the RFID recording medium and a reception signal from the RFID recording medium;
A signal processing unit that executes generation of the transmission signal and analysis of the reception signal based on communication specifications of the RFID recording medium, an antenna mechanism that should transmit the transmission signal, and an antenna mechanism that should receive the reception signal are selected. And a control mechanism having an antenna switching means. The control mechanism as the signal processing means,
A digital signal calculation unit that generates a digital modulation signal formed by superimposing a baseband signal representing the transmission data on a digital signal representing a carrier wave of a communication frequency in the communication specification;
The radio communication apparatus according to claim 6, further comprising: a signal conversion unit that converts the digital modulation signal into an analog signal and amplifies and outputs the analog signal as the transmission signal. The control mechanism as the signal processing means,
A first digital signal representing a standing wave of a predetermined frequency, and a digital signal computing unit for generating a second digital signal formed by superimposing a baseband signal representing the transmission data on the digital signal representing a standing wave of a predetermined frequency;
The first digital signal and the second digital signal are converted into a first analog signal and a second analog signal, the frequency of the first analog signal is converted into a communication frequency of the communication specification, and the communication A signal conversion unit that generates an analog modulation signal formed by superimposing the second analog signal on the first analog signal converted into a frequency, amplifies the analog modulation signal as the transmission signal, and outputs the amplified signal. The wireless communication apparatus according to claim 6. The signal conversion unit converts an analog signal as the reception signal into a digital signal,
The radio communication apparatus according to claim 7 or 8, wherein the digital signal calculation unit extracts a baseband signal from the digital signal converted by the signal conversion unit based on the communication specification. The communication information relating to the communication specification of the RFID recording medium is connected to a server device that holds the communication information in association with the RFID recording medium, and is communicably connected
The wireless communication device according to claim 6, wherein communication information corresponding to the RFID recording medium is acquired from the server device at the time of data writing and data reading.   A program causing a computer to function as the wireless communication apparatus according to claim 6.

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