JP4494896B2 - Noise analysis system, reader / writer - Google Patents

Description

  The present invention relates to a reader / writer that can write and read data to and from a non-contact type RFID tag, and a noise analysis system that analyzes external noise received by such a reader / writer. .

In recent years, new information recording media called IC cards are widely available on the market. The IC card is a generic name for cards having a card-like or sheet-like shape such as a credit card, a bank card, a point card, etc., and an IC (Integrated Circuit) incorporated in the card. In particular, non-contact type IC cards are used in combination with a magnetic card system at many stations as commuter passes and the like that are used when getting on and off train stations. In addition, since the non-contact IC card exchanges data with the reader / writer via radio waves, the standardization of the protocol, modulation waveform, and encoding between the reader / writer and the IC card is in progress. In particular, in this standardization, 13.56 MHz, which is widely used for industrial, scientific, and medical purposes, is used as the carrier frequency, and the problem of radio wave interference between devices has been highlighted. In other words, the influence of the interference wave on the reader / writer is increasing, which leads to the malfunction of the reader / writer, and the reader / writer himself needs to detect the interference wave in advance and take countermeasures. Yes.
As described above, since the reader / writer exchanges data by radio waves, it is highly convenient but highly reliable. In other words, there is a need to suppress data misrecognition due to external noise from other devices using the same carrier frequency as much as possible. However, since the weak radio waves from the IC card are received and data is exchanged, the reception sensitivity is relatively high. When strong radio waves are radiated from the outside, interference caused by mutual radio waves and other malfunctions due to noise This is a problem that cannot be ignored.
Therefore, Patent Document 1 includes a magnetic field strength measurement unit that measures the magnetic field strength of the carrier wave received by the loop antenna, detects the presence of external noise in advance, and informs the operator of the result, A technique related to a reader / writer that can quickly eliminate the influence of external noise is disclosed.
In Patent Document 2, noise from an electronic device is received by an antenna, and the received signal is input to a spectrum analyzer to analyze frequency components and intensity, thereby performing quantitative noise measurement. A technique related to the EMI automatic measuring apparatus is disclosed.
JP 2004-48288 A JP-A-5-264619

However, although the reader / writer disclosed in Patent Document 1 can detect the presence or absence of external noise, it cannot detect the frequency component or intensity of external noise, and thus finds the cause of external noise. I couldn't.
Further, in the EMI automatic measurement apparatus disclosed in Patent Document 2, in order to measure noise in the installation environment where the reader / writer is installed, it is necessary to bring in expensive measurement equipment such as a spectrum analyzer in the installation environment. Moreover, it was necessary for a skilled engineer to perform the measurement work.
Therefore, the present invention has been made in view of the above points, and an object thereof is to provide a reader light and a noise analysis system that can easily perform noise measurement in an installation environment in which a reader / writer is installed. To do.

In order to achieve the above object, the present invention according to claim 1 is configured to transmit carrier power and data to and from an RFID tag by transmitting a carrier wave modulated by a predetermined modulation method via a loop antenna. In a reader / writer that performs transmission and reception in a non-contact manner, an accumulation unit that accumulates a detection signal obtained by detecting a reception signal received via the loop antenna, and a filter unit that removes a required frequency band component included in the reception signal; A communication unit that enables communication with an external device via a communication network; and a control for transmitting the detection signal stored in the storage unit to the external device via the communication network. Control means for controlling the filter characteristics of the filter means based on operation information transmitted from the external device via Characterized by comprising a.
A second aspect of the present invention includes A / D conversion means for converting an analog signal level of the detection signal into a digital code signal, and the storage means is a digital code signal converted by the A / D conversion means. It is characterized by accumulating.

According to a third aspect of the present invention, there is provided the reader / writer according to the first or second aspect , and the external device, the noise component included in the data transmitted from the reader / writer via the communication network. Noise comprising: an analysis device that performs analysis; and a communication device that enables communication between a communication unit provided in the reader / writer and a communication unit provided in the analysis device via the communication network Features an analysis system.

According to the first aspect of the present invention, the detection signal including the external noise detected from the reception signal received by the loop antenna in the reader / writer is accumulated in the accumulation means, and the accumulated detection signal is transmitted via the communication network. it is possible to transmit to the external apparatus, it is possible to perform an analysis of specialized external noise by an external apparatus connected via a communication network. In addition, since it becomes possible to control the filter characteristics of the filter means based on operation data transmitted from the external device via the communication network, it is possible to adjust the reader / writer in real time by the external device. become.
According to the second aspect of the present invention, the detection signal converted by the A / D conversion unit is stored in the storage unit, so that the amount of data stored in the storage unit can be increased and digitized. The processed signal can be handled, and the processing by the personal computer becomes easy.
According to the third aspect of the present invention, the reader / writer according to the first or second aspect is configured to be able to transmit analysis data to the analysis device via the communication network, so that the installation environment in which the reader / writer is installed. An analyzer connected via a communication network without measuring equipment such as a spectrum analyzer in the installation environment or dispatching skilled technicians to perform measurement work. It will be possible to perform specialized external noise analysis.

First, before describing a reader / writer as an embodiment of the present invention, the configuration and operation of a general reader / writer and a non-contact RFID (Radio Frequency IDentification) tag will be described.
FIG. 1 is a block diagram showing the configuration of the reader / writer.
The reader / writer 100 shown in FIG. 1 controls a data communication protocol between an external computer 50 and a computer (host device) 50 that is externally provided to the reader / writer 100 to exchange data and control the entire system. The transmission / reception device 1, the control device 2 that controls the operation of the reader / writer 100 as a whole, the firmware that records the procedure for operating the control device 2, the memory device 3 that stores the read data, and the data from the control device 2 as a carrier wave A modulator 4 that modulates the signal, an input device 5 that inputs an operation command, a display device 6 that displays information controlled by the control device 2, a power amplifier 7 that amplifies the command from the modulator 4, A detector demodulator 8 for converting the carrier wave received from the loop antenna unit 9 into binary data, and an RFI not shown in this figure It includes a loop antenna unit 9 for exchanging electric power carrier wave and data between the tag 200 is configured.

Next, before describing the operation of the reader / writer 100 according to the present configuration, the configuration of a pair of RFID tags will be described.
FIG. 2 is a block diagram showing the configuration of the RFID tag.
The RFID tag 200 shown in FIG. 2 receives a loop antenna unit 20 that transmits and receives data using a power carrier wave from the reader / writer 100, and a power carrier wave from the loop antenna unit 20, and rectifies and converts it into DC power. A rectifying / smoothing circuit 22, a memory device 23 that manages control firmware and data, a modulator 24 that modulates a transmission command from the control circuit 26 with a carrier wave, and binarization from carrier wave data from the transmission / reception circuit 21. It comprises a detector 25 that converts data and a control circuit 26 that controls the overall operation of the RFID tag 200.
In addition to the ASK (Amplitude Shift Keying) which is a kind of amplitude modulation method, the modulation method may be a PSK (Phase Shift Keying) method, an FSK (Frequency Shift Keying) method, or the like.

Next, each operation will be described with reference to FIGS. 1 and 2 together.
When a power supply (not shown) is turned on, the reader / writer 100 starts an operation according to a program stored in the memory device 3 after the initial operation of the control device 2. First, initialization is performed. Next, in order to supply power to the RFID tag 200, the control device 2 performs modulation by the modulator 4 at the time of command transmission, and transmits a non-modulated signal from the power amplifier 7 at the time of response reception from the RFID tag 200. To do. The signal is radiated to the outside from the loop antenna unit 9 as an electromagnetic wave. Next, when the RFID tag 200 comes close to the reader / writer 100, the loop antenna unit 20 receives the power supply signal, rectifies the carrier wave by the rectifying / smoothing circuit 22 and converts it to DC power, Supply to the circuit. When power is supplied and the control circuit 26 is driven, control is started in accordance with a program stored in the memory device 23.
Next, the control circuit 26 first demodulates the command from the transmission / reception circuit 21 by the detector 25, converts it to a binary signal, and analyzes the command. As a result, when it is recognized that it is called, the response is modulated by the modulator 24 and transmitted from the loop antenna unit 20 via the transmission / reception circuit 21. The reader / writer 100 receives the response from the loop antenna unit 9 and converts it into a binarized code by the detector demodulator 8 and analyzes it by the control circuit 2 to recognize that the RFID tag 200 is a tag conforming to the standard. . Thereby, data is exchanged between the reader / writer 100 and the RFID tag 200 thereafter.

Hereinafter, the reader / writer according to the present embodiment will be described based on the operation description of the reader / writer 100 and the RFID tag 200 described above.
FIG. 3 is a block diagram showing the configuration of the reader / writer according to the first embodiment.
It should be noted that the same blocks as those in FIG.
As shown in FIG. 3, in the reader / writer 11 as the present embodiment, the analog signal level of the detection signal received by the loop antenna 9 and detected by the detection demodulator 8 is converted into a digital code signal (hereinafter referred to as “detection data”). A / D converter 12 for converting to A) and a storage device 13 for storing the detection data A / D converted by the A / D converter 12. In this case, the storage device 13 is configured by a storage medium that can be recorded and read, and stores detection data digitally converted by the A / D converter 12.
Such a storage device 13 uses, for example, a semiconductor medium such as a nonvolatile memory card, an optical medium such as a DVD, MO, MD, and CD-R, a magneto-optical medium, or a magnetic medium such as a magnetic tape and a flexible disk. It is conceivable to configure.

FIG. 4 is a diagram showing an internal configuration of the detector demodulator 8 provided in the reader / writer 11 according to the present embodiment.
FIG. 4A is a diagram illustrating a configuration of a detection demodulator when a transmission signal transmitted from the RFID tag 200 does not include a subcarrier.
The detector demodulator 8 shown in FIG. 4A includes a detector 31, a waveform shaper 32, and a decoding circuit 33.
The detector 31 detects a received signal received by the loop antenna 9. The detection signal detected by the detector 31 is supplied to the waveform shaper 32, shaped by the waveform shaper 32, decoded by the decoding circuit 33, and supplied to the control device 2. In this case, the detection signal output from the detector 31 is also input to the A / D converter 12, converted into detection data by the A / D converter 12, and stored in the storage device 13.
FIG. 4B is a diagram illustrating a configuration of a detection demodulator when a transmission signal transmitted from the RFID tag 200 includes a subcarrier.
4B includes a detector 31, a secondary detector 34, a waveform shaper 32, and a decoding circuit 33. The detection demodulator 8a shown in FIG.
In this case, the detector 31 detects the received signal received by the loop antenna 9 and then the secondary detector 34 detects the subcarrier. Then, the detection signal detected by the secondary detector 34 is supplied to the waveform shaper 32, shaped by the waveform shaper 32, decoded by the decoding circuit 33, and supplied to the control device 2. . In this case, the detection signal output from the secondary detector 34 is input to the A / D converter 12, converted into detection data by the A / D converter 12, and stored in the storage device 13. Become.
As described above, in the reader / writer 11 according to the first embodiment, the analog detection signal detected by the detection demodulator 8 is converted into digital detection data by the A / D converter 12 and then stored by the storage device 13. Accumulate.

With this configuration, the waveform of the detection data stored in the storage device 13 can be displayed on the display device 6. Therefore, the reader / writer 11 can use the waveform displayed on the display device 6 to detect external noise. It is possible to easily identify the generation factor.
In addition, by storing the detection data converted by the A / D converter 12 in the storage device 13, it is possible to increase the amount of data stored in the storage device 13 and handle a digitized signal. This makes it possible to facilitate processing on a host computer such as a personal computer.
In this embodiment, the analog detection signal detected by the detection demodulator 8 is converted into digital detection data by the A / D converter 12 and then stored in the storage device 13. It is merely an example, and the analog detection signal detected by the detection demodulator 8 can be stored in the storage device 13 as an analog signal without A / D conversion. In this case, the A / D converter 12 is not necessary, and the cost can be reduced accordingly.
By the way, in the reader / writer 11 according to the first embodiment described above, the detection signal detected by the detection demodulator 8 is stored in the storage device 13, and the waveform of the stored detection data is displayed on the display device 6. However, for example, if the detection data stored in the storage device 13 of the reader / writer 11 is transmitted to an expensive measuring instrument such as a spectrum analyzer or a management center on which a skilled engineer is waiting, the external data included in the detection data It is also possible to perform a detailed analysis of noise.

FIG. 5 is a diagram showing the configuration of the noise analysis system according to the first embodiment of the present invention.
In the noise analysis system shown in FIG. 5, the reader / writer 11 having a block configuration as shown in FIG. 3 and the management center 41 are connected via a communication network 42. Therefore, the reader / writer 11 is provided with a communication device 43 for establishing communication with the communication network 42, and the management center 41 is similarly provided with a communication device 44 for establishing communication with the communication network 42. Is provided.
In this case, the communication network 42 may be a wired or wireless public line network or a dedicated line. Further, for example, it is conceivable to apply the Internet, a satellite communication network, an optical fiber network, and other various communication lines.
The management center 41 is provided with an analysis device 45 such as an FFT (Fast Fourier Transform) spectrum analyzer. The analysis data is transmitted from the reader / writer 11 via the communication network 42 by the analysis device 45. Analysis is performed.
As described above, in the noise analysis system according to the first embodiment, the detection data detected by the reader / writer 11 is transmitted to the management center 41 via the communication network 42, and the analysis provided in the management center 41 is performed. The detection data is analyzed by the device 45.
With this configuration, when measuring external noise in the installation environment in which the reader / writer 11 is installed, an analyzer 45 such as a spectrum analyzer is brought into the installation environment in which the reader / writer 11 is installed, or measurement work is performed. The management center 41 connected by the communication network 43 can perform specialized external noise analysis without dispatching a skilled engineer to perform the operation.
At this time, the detection data detected by the reader / writer 11 is stored in the storage device 13, then transmitted to the management center 41 via the communication network 42, and detected data by the analysis device 45 provided in the management center 41. When the above analysis is performed, the analysis process in the analysis device 45 can be performed in a short time.

FIG. 6 is a diagram showing a configuration of a noise analysis system according to the second embodiment of the present invention.
In the noise analysis system shown in FIG. 6, the reader / writer 60 and the management center 41 are connected via the communication network 42. In this case, the reader / writer 60 includes, for example, the loop antenna 9 and the detection demodulator. 8 is provided with an active filter circuit 61.
The active filter circuit 61 is configured to remove a signal having a required frequency band component contained in the received signal received by the loop antenna 9 under the control of the control circuit 2. In this case, the control unit 2 controls the filter characteristic of the active filter circuit 61 based on operation information transmitted from the input device 46 of the management center 41 via the communication network 42.
On the other hand, the management center 41 is provided with an input device 46. By inputting operation data through the input device 46, the filter characteristics of the active filter circuit 61 provided in the reader / writer 60 can be remotely controlled. ing.
Therefore, according to such a noise analysis system, the analysis device 45 of the management center 41 analyzes the detection data transmitted from the reader / writer 61 via the communication network 42. Based on the analysis result, the engineer of the management center 41 operates the input device 46 so that the filter characteristics of the active filter circuit 61 of the reader / writer 60 can be controlled via the communication network 42. Become. That is, the filter adjustment of the reader / writer 60 can be performed in real time by the management center 46.
In this embodiment, an active filter whose characteristics can be varied, such as a switched capacitor filter circuit, has been described as an example. However, this is only an example, and any filter circuit whose characteristics can be changed is applicable. is there.
The configuration of the reader / writer as the present embodiment described so far is merely an example, and the configuration of the reader / writer of the present invention is not limited to the present embodiment.

It is a block diagram for demonstrating operation | movement of a reader / writer. It is a block diagram for demonstrating operation | movement of a RFID tag. It is the figure which showed schematic structure of the reader / writer which concerns on embodiment of this invention. It is the block diagram which showed the internal structure of the detection demodulator. It is the figure which showed schematic structure of the noise analysis system which concerns on the 1st Embodiment of this invention. It is the figure which showed schematic structure of the noise analysis system which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Transmission / reception apparatus, 2 Control circuit, 3 Memory apparatus, 4 Modulator, 5 Input apparatus, 6 Display apparatus, 7 Power amplifier, 8, 8a Detection demodulator, 9 Loop antenna, 11 Reader / writer, 12 A / D converter, 13 storage device, 31 detector, 32 waveform shaper, 33 decoding circuit, 34 secondary detector, 41 management center, 42 communication network, 43, 44 communication device 45 analysis device, 46 input device, 50 host device, 60 reader Writer, 61 active filter circuit

Claims (3)

In a reader / writer that transmits carrier power and exchanges data with an RFID tag in a non-contact manner by transmitting a carrier wave modulated by a predetermined modulation method via a loop antenna,
Storage means for storing a detection signal obtained by detecting a reception signal received via the loop antenna;
Filter means for removing a required frequency band component contained in the received signal;
Communication means for enabling communication with an external device via a communication network;
Control for transmitting the detection signal stored in the storage means to the external device via the communication network, and the filter means based on operation information transmitted from the external device via the communication network Control means for controlling the filter characteristics of
A reader / writer characterized by comprising: An A / D conversion means for converting an analog signal level of the detection signal into a digital code signal is provided, and the storage means stores the digital code signal converted by the A / D conversion means. The reader / writer according to 1 . The reader / writer according to claim 1 or 2 ,
An analysis device for analyzing a noise component included in data transmitted from the reader / writer via the communication network, the external device;
A communication device that enables communication between the communication means provided in the reader / writer and the communication means provided in the analysis device via the communication network;
A noise analysis system characterized by comprising:

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