JP2006093887A - Data reader and communication element without power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication element without power supply that dispenses with a high-frequency oscillator, has a simple circuit configuration, and consumes only a small amount of power; and to provide a data reader for reading the data. <P>SOLUTION: The reception antenna 21 of the communication element without power supply 20 receives a signal for supplying power from a transmission antenna 13 in a reader 10. A rectifier 22 rectifies a signal received by the reception antenna 21, generates a supply voltage, and supplies it to each part of the communication element without power supply 20. A modulator 23 receives the supply of power from the rectifier 22 and modulates a carrier from the reception antenna 21 by a digital transmission signal. A spectrum diffuser 24 performs the spectrum diffusion of a signal modulated by the modulator 23 by those without any DC components in Hadamard codes. A transmission antenna 25 radiates a signal that is subjected to spectrum diffusion by the spectrum diffuser 24 to a reception antenna 14 in the reader 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data reading device that reads data from a non-power source communication element such as a non-contact type IC (Integrated Circuit) card, and the non-power source communication element, and more particularly, to a data reading device that enables high-speed communication with a simple configuration, and The present invention relates to a non-power supply communication element.

  As a conventional non-power supply communication element, for example, in RFID (Radio Frequency Identification), a frequency for receiving power supply and a frequency for information transmission are separated to prevent interference.

  In addition, in order to improve the signal-to-noise ratio, there is also a type of receiving a power supply at a low frequency and transmitting a signal by spectrum-spreading a high-frequency carrier wave (see, for example, Patent Document 1).

  FIG. 5 is a diagram showing a configuration of a conventional data reading device and a non-power supply communication element. A reader 30 as a data reading device includes a low frequency oscillator 31, an amplifier 32, a transmission antenna 33, a reception antenna 34, a filter 35, a linear amplifier (LNA) 36, a high frequency oscillator 37, a mixer 38, a spectrum despreader 39, and a demodulation. It consists of a container 40. The non-power source communication element 50 includes a reception antenna 51, a rectifier 52, a high frequency oscillator 53, a modulator 54, a spectrum spreader 55, and a transmission antenna 56. The low-frequency oscillator 31 of the reader 30 oscillates a low-frequency signal for power supply, the amplifier 32 amplifies it, and the transmission antenna 33 that is a coil radiates the reception antenna 51 of the power-less communication element 50. The receiving antenna 51 receives a low-frequency signal for power supply from the transmitting antenna 33 of the reader 30. The rectifier 52 rectifies the low-frequency signal received by the receiving antenna 51 to generate a power supply voltage and supplies it to each part of the non-power supply communication element 50. The high frequency oscillator 53 is supplied with power from the rectifier 52 and generates a high frequency signal which becomes a carrier wave for signal transmission. The modulator 54 also receives power from the rectifier 52 and modulates the carrier wave from the high frequency oscillator 53 with the digital transmission signal. As a modulation method, an FSK (Frequency Shift Keying) modulation method, an ASK (Amplitude Shift Keying) modulation method, or the like can be used. The spectrum spreader 55 spreads the signal modulated by the modulator 54 with an M-sequence code or the like. The transmission antenna 56 radiates the signal spectrum-spread by the spectrum spreader 55 to the reception antenna 34 of the reader 30. The reception antenna 34 receives a signal from the transmission antenna 56 of the non-power supply communication element 50. The filter 35 allows a signal in a predetermined band that has been spread spectrum received by the receiving antenna 34 to pass therethrough. The linear amplifier 36 linearly amplifies the signal. The high frequency oscillator 37 oscillates the same frequency signal as that of the high frequency oscillator 53 of the power-less communication element 50. The mixer 38 converts the high frequency signal into a baseband signal. The spectrum despreader 39 decodes the signal that has been subjected to spectrum spread by being encoded. The demodulator 40 converts the decoded analog signal into a digital signal and demodulates the digital transmission signal from the powerless communication element 50.

As described above, the reader 30 supplies power at a low frequency and receives a signal obtained by spectrum-spreading a high frequency carrier wave in order to receive a signal simultaneously with supplying power.
Japanese Patent No. 2874368

  However, the above-described conventional example requires a high-frequency oscillator that generates a carrier wave for transmitting a signal, and the circuit configuration becomes complicated, and the power consumption in the non-power supply communication element that receives power supply increases. End up.

  SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a non-power source communication element that does not require a high-frequency oscillator and consumes less power with a simple circuit configuration, and a data reading device that reads the data.

  The data reading device of the present invention includes an oscillator that oscillates a high-frequency signal, a transmission antenna that radiates a radio wave having the high-frequency signal oscillated by the oscillator as a carrier wave, and a radio wave from the power-less communication element. A receiving antenna for receiving, a filter for attenuating the frequency component of the carrier wave of the radio wave received by the receiving antenna, and a high-frequency signal from the oscillator mixed with a high-frequency signal that has passed through the filter is converted into a baseband signal. A mixer, a spectrum despreader that despreads the signal from the mixer, and a demodulator that demodulates the signal from the spectrum despreader are provided.

  In addition, the data reading device of the present invention includes an oscillator that oscillates a high-frequency signal, a transmission antenna that radiates a radio wave having the high-frequency signal oscillated by the oscillator as a carrier wave, and a power supply communication element. A reception antenna that receives radio waves, a filter that attenuates the frequency component of the carrier wave of radio waves received by the reception antenna, and a high-frequency signal from the oscillator mixed with a high-frequency signal that has passed through the filter into a baseband signal A mixer for conversion, a demodulator for demodulating a signal from the mixer, and a spectrum despreader for spectrum despreading the signal from the demodulator are provided.

  In addition, the spectrum despreader can cancel the DC offset component by despreading by performing spectrum despreading with a code having no DC component.

  The power-less communication element of the present invention includes a receiving antenna that receives a radio wave from a data reading device, a rectifier that rectifies the radio wave received by the antenna and uses it as a power source, and operates with the power source of the rectifier. A modulator that modulates the carrier wave with a transmission signal, a spectrum spreader that spreads the signal from the modulator, and a transmission antenna that radiates the signal from the spectrum spreader to the data reading device.

  The power-less communication element of the present invention includes a receiving antenna that receives a radio wave from a data reading device, a rectifier that rectifies the radio wave received by the antenna and uses it as a power source, and a spectrum spreader that spreads a transmission signal. And a modulator that operates with the power source of the rectifier and modulates the carrier wave of the radio wave with a signal from the spectrum spreader, and a transmission antenna that radiates the signal from the spectrum spreader to the data reading device.

  Further, the spectrum spreader performs spectrum spread using a code having no DC component, so that the DC offset component can be canceled by despreading in the data reading device.

  In addition, since the transmission antenna and the reception antenna also serve as one antenna, the circuit scale can be further reduced.

  According to the present invention, a spread spectrum signal can be transmitted to the data reading device at the same time that power is supplied from the data reading device without requiring a high-frequency oscillator for the power-free communication element. For this reason, it is possible to perform ultrahigh-speed data transmission with a simple circuit configuration.

  The best mode for carrying out the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a configuration of a data reading device and a non-power source communication element according to an embodiment of the present invention. A reader 10 as a data reading device includes an oscillator 11, an amplifier 12, a transmission antenna 13, a reception antenna 14, a filter 15, a linear amplifier (LNA) 16, a mixer 17, a spectrum despreader 18, and a demodulator 19. The non-power source communication element 20 includes a reception antenna 21, a rectifier 22, a modulator 23, a spectrum spreader 24, and a transmission antenna 25. The oscillator 11 of the reader 10 oscillates a signal that is a carrier frequency for signal transmission from the powerless communication element 20 and is used to supply power to the powerless communication element 20, and the amplifier 12 amplifies it, The transmitting antenna 13 that is a coil radiates to the receiving antenna 21 of the power-less communication element 20. The reception antenna 21 receives a power supply signal from the transmission antenna 13 of the reader 10. The rectifier 22 rectifies the signal received by the receiving antenna 21 to generate a power supply voltage, and supplies it to each part of the non-power supply communication element 20. The modulator 23 receives power from the rectifier 22 and modulates the carrier wave from the receiving antenna 21 with a digital transmission signal. The spectrum spreader 24 spreads the signal modulated by the modulator 23 using a Hadamard code having no DC component.

  The Hadamard code is a code in which a row or a column of a matrix generated by the following method among orthogonal codes is used.

  The transmission antenna 25 radiates the signal spectrum-spread by the spectrum spreader 24 to the reception antenna 14 of the reader 10. The reception antenna 14 receives a signal from the transmission antenna 25 of the powerless communication element 20. The filter 15 is a band-pass filter that allows a spectrum-spread signal of a predetermined band received by the receiving antenna 14 to pass therethrough, and is an oscillation frequency component of the oscillator 11, and is a carrier frequency of a transmission signal from the power-less communication element 20. It is a notch filter that attenuates the component to such an extent that the linear amplifier 16 is not saturated. The linear amplifier 16 linearly amplifies the signal. The mixer 17 converts the high frequency signal into a baseband signal. The spectrum despreader 18 decodes the signal that has been subjected to spectrum spread by being encoded. The demodulator 19 converts the decoded analog signal into a digital signal and demodulates the digital transmission signal from the powerless communication element 20.

  FIG. 2 is a diagram for explaining the demodulation operation of this embodiment. FIG. 2 (a) shows the frequency characteristics of the signal input to the filter 15, and the reader 10 of this embodiment receives the signal simultaneously with the transmission of power. There is a large carrier frequency component in which the wideband signal and the transmitted carrier signal circulate to the receiving side. This carrier frequency component is assumed to be about 90 dB larger than the spread spectrum signal. FIG. 2 (b) shows the frequency characteristics of the signal output from the filter 15, and the carrier frequency component of the spread spectrum signal is attenuated together with the carrier signal. However, since the spread spectrum signal has a wide band, there is no problem with the spread spectrum spread. FIG. 2 (c) shows the frequency characteristics of the signal after despreading, which is a signal of a predetermined frequency component, and in the present embodiment, it is a baseband signal.

  For each of the case where the M-sequence code {-1 -1 -1 1 -1 1 1} is used as the code and the case where the Hadamard code {-1 -1 1 1 -1 -1 1 1} is used, Explain the impact. Assuming that the interference component I is added to the signal component S, the influence of the interference component I in the despreading process can be shown as follows. Here, the influence of noise is ignored.

  As described above, when an M-sequence code having a DC component is used, the DC offset component remains even after despreading. However, when a Hadamard code having no DC component is used in the code itself, The DC offset component can be canceled by despreading. Therefore, even if a large carrier frequency component in which the transmitted carrier signal circulates to the receiving side passes through the filter 15 to some extent, this can be canceled. For this reason, the power supply signal and the information transmission signal carrier can be handled at the same frequency.

  FIG. 3 is a diagram illustrating the radio regulation of a normal RFID. An electric field strength of 316 μV / m at a center frequency of 13.56 MHz and a distance of 10 m is a narrow band of ± 450 kHz and is not suitable for high-speed data transmission.

  FIG. 4 is a diagram illustrating weak radio regulations. The permissible electric field strength is 500 μV / m at a distance of 3 m (35 μV / m in some bands), but the band is wide but suitable for high-speed data transmission. Can be used.

  In addition, this invention is not limited to the said Example.

  In the above embodiment, the reader 10 demodulates the spectrum after despreading, and the powerless communication element 20 modulates the spectrum and then spreads the spectrum. However, one or both may be reversed. That is, the reader 10 demodulates, that is, analog-to-digital conversion, and then performs spectrum despreading, that is, decoding, and the power-less communication element 20 performs spectrum spreading, that is, encodes and then modulates, that is, digital Analog conversion may be performed.

  In the above-described embodiment, the signal is transmitted in one direction from the powerless communication element 20 to the reader 10. However, a bidirectional communication configuration in which a signal is transmitted from the reader 10 to the powerless communication element 20 can also be employed. In this case, the reader is a reader / writer, that is, a data read / write device, and includes a modulator and a spectrum spreader, and the non-power supply communication element includes a spectrum despreader and a demodulator. When the bidirectional communication is configured to be transmitted and received at the same time, for example, different codes may be used for transmission and reception. Of course, when the transmission / reception is performed in a time division manner, the same code can be used for the transmission / reception.

  In the above embodiment, the reader 10 and the power-less communication element 20 are both provided with a transmission antenna and a reception antenna. . In this case, the transmission side and the reception side are isolated using a circulator or the like.

  In addition to the configuration of the above-described embodiment or in place of the notch filter, it is possible to invert and attenuate the carrier frequency component on the transmission side and attenuate the carrier frequency component on the reception side in addition to the reception side.

  The non-power supply communication element may have a CPU (Central Processing Unit) or may not have a CPU. Further, the form of the power-less communication element may be a label type, a card type, a box type, or the like.

It is a figure which shows the structure of the data reading device by one Example of this invention, and a non-power-supply communication element. It is a figure explaining the operation | movement of the demodulation of a present Example. It is a figure which shows the radio | wireless prescription | regulation of normal RFID. It is a figure which shows weak radio prescription | regulation. It is a figure which shows the structure of the conventional data reading apparatus and a non-power-supply communication element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reader 11 Oscillator 12 Amplifier 13 Transmitting antenna 14 Receiving antenna 15 Filter 16 Linear amplifier 17 Mixer 18 Spectrum despreader 19 Demodulator 20 Power-less communication element 21 Receiving antenna 22 Rectifier 23 Modulator 24 Spectrum spreader 25 Transmitting antenna 30 Reader 31 Low frequency oscillator 32 Amplifier 33 Transmitting antenna 34 Reception antenna 35 Filter 36 Linear amplifier 37 High frequency oscillator 38 Mixer 39 Spectrum despreader 40 Demodulator 50 Power-less communication element 51 Reception antenna 52 Rectifier 53 High frequency oscillator 54 Modulator 55 Spectrum spreader 56 Transmit antenna

Claims (8)

An oscillator that oscillates a high-frequency signal;
A transmission antenna that radiates a radio wave having a high-frequency signal oscillated by the oscillator as a carrier wave to a non-power-supply communication element;
A receiving antenna for receiving radio waves from the power-less communication element;
A filter that attenuates the frequency component of the carrier wave of the radio wave received by the receiving antenna;
A mixer that mixes the high-frequency signal from the oscillator with the high-frequency signal that has passed through the filter and converts it to a baseband signal;
A spectrum despreader for spectrum despreading the signal from the mixer;
A data reading apparatus comprising: a demodulator that demodulates a signal from the spectrum despreader. An oscillator that oscillates a high-frequency signal;
A transmission antenna that radiates a radio wave having a high-frequency signal oscillated by the oscillator as a carrier wave to a non-power-supply communication element;
A receiving antenna for receiving radio waves from the power-less communication element;
A filter that attenuates the frequency component of the carrier wave of the radio wave received by the receiving antenna;
A mixer that mixes the high-frequency signal from the oscillator with the high-frequency signal that has passed through the filter and converts it to a baseband signal;
A demodulator that demodulates the signal from the mixer;
A data reading apparatus comprising: a spectrum despreader that despreads a signal from the demodulator.   3. The data reading apparatus according to claim 1, wherein the spectrum despreader performs spectrum despreading using a code having no DC component.   4. The data reading apparatus according to claim 1, wherein the transmitting antenna and the receiving antenna are used as one antenna. A receiving antenna for receiving radio waves from the data reading device;
A rectifier that rectifies radio waves received by the antenna and uses it as a power source;
A modulator that operates with the power source of the rectifier and modulates the carrier wave of the radio wave with a transmission signal;
A spectrum spreader that spreads the signal from the modulator;
A power-less communication element, comprising: a transmission antenna that radiates a signal from the spectrum spreader to a data reading device. A receiving antenna for receiving radio waves from the data reading device;
A rectifier that rectifies radio waves received by the antenna and uses it as a power source;
A spread spectrum spreader that spreads the transmission signal, and
A modulator that operates with the power supply of the rectifier and modulates the carrier wave of the radio wave with a signal from the spectrum spreader;
A power-less communication element, comprising: a transmission antenna that radiates a signal from the spectrum spreader to a data reading device.   7. The powerless communication element according to claim 5, wherein the spectrum spreader performs spectrum spread by a code having no DC component.   The powerless communication element according to any one of claims 5 to 7, wherein the transmitting antenna and the receiving antenna also serve as one antenna.

Images