JP2000151458A - Electromagnetic induction type transponder system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody high reliability, stability and wide-range transmission distance with low cost by constituting a system of a transponder having a modulation part modulating information to be transmitted and a memory part processing two pieces of received information and information to be transmitted and writing/reading information. SOLUTION: The transmission part (a) of an installation-type transmission/ reception device connected to a computer has two independent transmission devices. A first transmission frequency and a second transmission frequency from the first transmission device and the second transmission device are always and simultaneously transmitted. The antenna part and the reception part (b) of the transponder incorporate three types of independent magnetic field antennas and one type of resonation circuit. Magnetic field power components which are induced by the antenna are branched into three. One branched component becomes the driving power of an inner circuit. The next branched component is demodulated by detection circuits and two pieces of demodulated information are suitably processed in a memory part writing/reading information.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic induction type transponder system which is one form of a wireless transmission system, and relates to a non-contact card or the like which can identify an object or a person and store / read information without contact. The present invention relates to a wireless automatic transmission / reception device.

[0002]

2. Description of the Related Art In an electromagnetic induction type transponder system used up to now, a stationary transmitter / receiver transmits only one transmission frequency and carries information to be transmitted. In the operation of the transponder at this time, first, a signal in a non-modulated state is received for a certain period of time, and power operable by an internal circuit is generated and accumulated from the received magnetic field power. Next, the transmitted information is received and processed.

[0003] Further, a carrier wave is generated and transmitted with information to be transmitted. In this process, the generation of the carrier wave and the supply of the carrier wave power use the power stored in advance, so that the transmission speed is increased and the power consumption is suppressed.
The transmission power is limited by itself. As a result, the conventional method has the following disadvantages.

(A) A non-modulation transmission time necessary and sufficient for power storage is required, and a total transmission time is long. (B) Due to restrictions on stored power, information to be transmitted must be sent in a short time, resulting in reduced reliability of the transmitted information. (C) The transmission frequency and transmission power must be supplied from the stored power, and a large transmission power cannot be obtained. As a result, the communication distance is short.

[0005]

SUMMARY OF THE INVENTION The conventional system inevitably has a long transmission time from the stationary transmitter / receiver, instability of the transmission frequency from the transponder, and a decrease in the reliability of transmission information due to a high transmission speed. In addition, there are inconveniences such as a short communication distance due to a very small transmission power. Further, due to the method, the price of the transponder must be high.
The present invention can provide high reliability, high stability, low cost, and a wider transmission distance than these conventional systems.

[0006]

SUMMARY OF THE INVENTION The present invention originates from the development for simplifying the circuit and provides a system which can fundamentally improve the above-mentioned problems of the conventional system. The difference between this method and the conventional method is that
That is, the transmission frequency from the stationary transmission / reception device is not one but two. Based on this, various performance improvements that could not be realized by the conventional method can be solved at once. Further, it is possible to simplify the internal structure of the transponder according to the new method, and as a result, it is possible to realize a comprehensive cost reduction.

The principle of operation of the present system will be described. (B) The transmitting section of the stationary transmitting / receiving apparatus operates as follows. The transmission unit of the stationary transmission / reception device connected to the computer has two independent transmission devices.

[0008] From the first transmitter, a peak power of 10 W
And an electromagnetic wave of 132.0 KHz, which is an LF band frequency, which can be varied from the peak power to 0.5 W of peak power. From the second transmitting device, the peak power of 10 W to the peak power of 0.
196.0K which is LF band frequency that can be changed up to 5W
Hz electromagnetic waves are generated.

The first transmission frequency of 132.0 KHz
Is 12.926 MH oscillated by a highly stable crystal oscillator
It is generated by dividing z by two and dividing by two. In addition,
The reason why the frequency division is not performed at once is to obtain an accurate duty ratio of 50% by dividing the frequency by 2 in the final frequency divider. Similarly, the second transmission frequency of 196.0 kHz is 1
It is generated by dividing 2.926 MHz by 49 and 2.

[0010] The first transmission frequency and the second transmission frequency are always transmitted simultaneously. The transmission timing and the modulation of the information to be transmitted are all radiated by the connected computer.

The generated first transmission frequency and second transmission frequency components are simultaneously radiated to free space by independent magnetic field type antennas.

(B) The antenna unit and the receiving unit of the transponder operate as follows. The transponder contains three kinds of independent magnetic field type antennas and a kind of resonance circuit. The three magnetic field antennas are 13
It resonates at 2.0 KHz, 196.0 KHz, 328.0 KHz, and a kind of resonance circuit resonates at 64.0 KHz.

Now, 132.0 KHz and 196.0 KH
When z is received by each of the resonant antennas, the magnetic field power components induced in these antennas are branched into three. One of the branched components is converted into DC power by each rectifier circuit and becomes drive power for an internal circuit. Therefore, in this method, almost no non-modulation transmission time from the stationary transmission / reception device for power storage is required, and as a result, the communication time can be reduced.

The next one of the branched components is demodulated by each detection circuit. The two pieces of demodulated information are appropriately processed in a memory unit that performs writing / reading.

The last one of the branched components is generated by the passive non-linear element, which generates 328.0 KHz as a sum component and 64.0 KHz as a difference component. 328.0 KHz, which is a component of this sum, is modulated as a transmission signal, then guided as it is to a transmission magnetic field type antenna resonated at 328.0 KHz, and radiated to free space. In this process, the radiated power of 328.0 KHz and the radiated power are completely dependent on the two frequencies transmitted from the stationary transceiver.

That is, the radiated power at the transmission frequency is proportional to the two received powers. The difference component of 64.0 KHz is 6
After being guided to the 4.0 KHz resonance circuit, the frequency is divided by an n-stage frequency divider and used as a clock at the time of writing / reading of the memory unit. If 32, a 2 KHz clock is obtained, but this n value can be appropriately selected according to the communication protocol.

(C) The receiving section of the stationary transmission / reception apparatus operates as follows. The signal containing information of 328.0 KHz transmitted from the transponder is induced in the receiving magnetic field type antenna resonating at 328.0 KHz and has a strong component of 132.0 KHz.
Hz and 196.0 KHz are removed by a specific band attenuator, and unnecessary components are attenuated by a necessary band limiter, and then amplified to an amplitude required for demodulation. In this process, the reception electric field strength is detected, and it is determined whether or not the transmission state is normal.

Also, a 64.0 KHz component is generated from the signal used for generating the transmission frequency, similarly to the transponder, and divided by n to obtain a read clock. Since this clock matches the clock in the transponder, it is possible to demodulate the received information with high reliability.

As described above, in all cases, the transponder depends on the transmission frequency of the stationary transmission / reception device and the transmission power thereof, so that it is possible to exchange highly reliable name information.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, in order to avoid complexity, only one embodiment will be described. However, as described in the foregoing operation, if the operation principle is used, there are a wide variety of implementation methods. There is no wait for words to exist.

Based on the operation principle of the present invention, a block diagram of an installation type transmission / reception apparatus in which information to be transmitted is a binary digital signal and the method of modulating each carrier is the NRZ-ASK method. 1 is shown in FIG. 1, and a block diagram of the transponder is shown in FIG. Thus, the technical contents of the present invention can be easily understood.

[0019]

[Effect] As described above, since the transmission frequency from the stationary transmission / reception device is set to two instead of one, various performance improvements that could not be realized by the conventional method can be solved at once. According to this method, the internal structure of the transponder can be simplified, and as a result, the overall cost can be reduced.

In addition, by the electromagnetic induction type transponder system in which the stationary transmitting / receiving device simultaneously transmits two transmission frequencies, the state of initial control of the transponder can be performed with 2 bits, and power can be transmitted to the transponder. By using two frequencies compared to the case of using a single frequency, each transmission power can be halved, so that the influence on other communications can be reduced and restrictions on the electromagnetic law, etc. This is advantageous when considering the above.

Further, since the stationary transmission / reception device simultaneously transmits two transmission frequencies, the transmission frequency and its power that must be generated inside the transponder can be generated only by the passive nonlinear element, and the transmission frequency can be reduced. The stability and transmission power depend on the frequency and power of the two received waves. That is, an active circuit for transmission is not required inside the transponder, and the structure is simple.

[Brief description of the drawings]

FIG. 1 is a system diagram of an installation type transmitting / receiving apparatus.

FIG. 2 is a diagram of a transponder system

[Explanation of symbols]

 (B) Computer (b) Power supply (c) Crystal oscillator (d) Divider (e) Modulator (f) Power amplifier (g) Antenna (h) Passband limiting (r) RF amplification Section (v) Automatic gain control section (l) Power control section (ヲ) Electric field strength detection section (so) Power control section (f) Various input / output sections (yo) Antenna section (ta) Power generation section (v) Voltage stabilization (S) Reception DATA demodulation unit (T) Waveform shaping unit (D) Sum / difference frequency generation unit (N) Transmission DATA modulation unit (A) Memory unit (M) Frequency dividing unit.

Claims (4)

[Claims] 1. A transmission controlled by a computer, in which a first frequency including information 1 to be transmitted and a second frequency including information 2 to be transmitted are simultaneously transmitted from independent magnetic field type antennas. Unit, a stationary transmission / reception device comprising a reception unit for receiving and demodulating a signal transmitted from the automatic transmission / reception device and transmitting the transmitted information to a computer, and a first and a second frequency, respectively. Received simultaneously by independent magnetic field type antennas, one is a power supply unit that converts high frequency power generated from each received electromagnetic field to DC power and supplies power to an active circuit inside the receiving device, and a first and second power supply unit A demodulator for extracting each piece of information to be transmitted which is superimposed on a frequency, a transmission frequency generator for generating a third frequency as a transmission frequency from the received first and second frequencies, and transmitting information to be transmitted. frequency Inductive transponders method to a modulation unit, characterized in that respectively process the two received information and information to be transmitted is constituted by Totansuponda having a memory unit for writing / reading, etc. to be modulated. 2. The transponder according to claim 1, wherein the transponder does not have a power source such as a battery inside, and uses a power transmission in a space based on electromagnetic induction based on two transmission frequencies transmitted by the stationary transmission / reception device. And a frequency suitable for using the antenna by using a magnetic field type antenna.
An electromagnetic induction type transponder method characterized by selecting an LF band frequency of 0 KHz or less. 3. In Claims 1 and 2,
An electromagnetic induction type transponder system in which an initial state of a transponder is controlled by two bits by an electromagnetic induction type transponder system in which an installation type transmitting / receiving device transmits two transmission frequencies simultaneously. 4. The method according to claim 1, wherein:
An electromagnetic induction type transponder system, wherein a stationary transmission / reception device transmits two transmission frequencies simultaneously.