JP3006784B2 - Mobile station identification device by radio - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fixed station and a mobile station (I
The present invention relates to an apparatus for transmitting data to a mobile station (D card) by a mutual guidance method to identify a mobile station, and relates to a wireless mobile station identification apparatus in which the mobile station is driven without a battery.

[0002]

2. Description of the Related Art Conventionally, for transmitting data between a fixed station and a mobile station, there is, for example, an apparatus described in Japanese Patent Application Laid-Open No. Sho 64-80892. That is, when the fixed station side vibration energy is received by the receiver of the mobile station, a clock signal is generated by appropriately converting the AC component of the received vibration energy,
Thus, data is read out, a carrier wave is modulated with the data, and transmitted to the outside by a coupler.

[0003]

However, in the above-mentioned conventional apparatus, the modulation switch in the responder is turned on and off via a memory element from a program element or a memory. As described above, if the memory control element is interposed between the modulation switch and the program element or the memory, power consumption by the memory control element increases. Further, since this circuit has circuit elements for mode switching such as a level detector, a mode switching circuit, and a controllable switch element, power consumption is further increased. Therefore, a large amount of energy must be supplied from the transceiver, and the responder must have a large-capacity rectifying circuit for rectifying the energy. Therefore, there is a problem that the shape of the responder becomes large and the circuit configuration becomes complicated.

It is an object of the present invention to provide a device in which a mobile station (ID card) operates reliably without a battery and has a circuit configuration as small and simple as possible.

[0005]

According to the present invention, there is provided an apparatus for identifying a mobile station by transmitting data between a fixed station and a mobile station by a mutual guidance method. The mobile station 10 includes an LC resonance circuit 60 in which L and C resonating in the reception area of the high-frequency electromagnetic field are connected in parallel with each other, a capacitor 70, and a transistor 69. And a rectifying circuit 63 for rectifying the energy obtained in the LC resonance circuit 60 and supplying power by rectifying the energy obtained in the LC resonance circuit 60.
A clock extracting circuit 62 for extracting a clock from the LC resonance circuit 60, a frequency dividing circuit 64 for dividing the frequency of the clock extracting circuit 62, and an identification code data unique to the mobile station 10 based on an output of the frequency dividing circuit 64. And a serial ROM 68 for reading out and outputting to the modulation circuit 61, wherein the output of the serial ROM 68 is used as a direct drive source for turning on and off the transistor 69 of the modulation circuit 61. It is an identification device.

[0006]

A high frequency current is passed from the fixed station to the coil of the resonance circuit to form an electromagnetic field in the space, thereby obtaining a reception area. When the person with the ID card enters the reception area,
It resonates the resonance circuit built in the D card, extracts a clock signal synchronized with the resonance frequency of the electric energy induced in the coil, and reads a unique ID (identification) code.

The MOSFET 69 of the modulation circuit 61 is directly driven by the output of the identification code signal of the ID card to modulate the high frequency signal of the resonance circuit of the fixed station, to detect and demodulate the signal, and to input to the microcomputer. It is determined whether or not the identification code input by the microcomputer is registered.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, an ID card 10 as a mobile station is provided.
The voltage is induced in the built-in transmitting / receiving coil 71 based on the high-frequency electromagnetic field generated by the transmitting / receiving coil 59 of the fixed station 11, and transmits its own identification code by a so-called mutual induction method. The fixed station 11 will be described in detail with reference to FIG. 3, and the ID card 10 will be described in detail with reference to FIG.

Referring to FIG. 3, the fixed station 11 comprises a transmission / reception coil 59 and a capacitor, which form a high-frequency electromagnetic field in the space and transmit / receive an RF resonance circuit 50, and an envelope detection for extracting an envelope signal from a received signal. Circuit 51
An active filter circuit 52 for passing only the data signal; a comparator circuit 53 for converting the data signal into a binary digital signal;
A microcomputer 54 that exchanges signals with the microcomputer 54, an oscillation circuit 55 that generates a high-frequency signal, a switch circuit 56 that turns on and off to output an oscillation signal from the microcomputer 54 at fixed time intervals, It comprises an amplifying circuit 57 for amplifying and a booster circuit 58 for amplifying current.

In FIG. 2, the ID card 10 includes an LC resonance circuit 60 that resonates with a high-frequency electromagnetic field formed in the space by the coil 59 of the fixed station 11, and converts the energy obtained by the resonance into DC power. Rectifier circuit 63 for driving the internal elements, a clock extracting circuit 62 for extracting a clock synchronized with the resonance frequency, a frequency dividing circuit 64 for dividing the extracted clock, and a memory for storing identification code data unique to itself. Serial ROM 68 and the fixed station 11
Modulation circuit 6 for AM-modulating the frequencies at both ends of coil 59 of FIG.
It consists of 1.

The LC resonance circuit 60 comprises a parallel circuit of a coil 71 and a capacitor 72,
Is a first clock generation circuit 6 that divides the clock by 64
5, a second clock generation circuit 66 for dividing the clock signal of the first clock generation circuit 65 by 128, and an inverter circuit 67. The modulation circuit 61
Transistor 69 as a switch element such as an SFET
And a capacitor 70.

The operation of the above configuration will be described with reference to waveform diagrams. (1) When the power is supplied to the fixed station central management unit 40, the switch circuit 56 is turned on and off by a signal from the microcomputer 54, and a high-frequency signal is repeatedly sent to the fixed station 11 at regular time intervals.

(2) In response to a command from the microcomputer 54, the switch 56 is turned on as shown in FIG.
00 ms), the high-frequency signal of the oscillation circuit 55 is sent to the LC resonance circuit 50 via the amplification circuit 57 and the booster circuit 58, and the high-frequency electromagnetic field as shown in FIG. To form a reception area.

(3) Here, it is assumed that a person (mobile station) carrying the ID card 10 has entered the high-frequency electromagnetic field reception area of the fixed station 11. At this time, even when the ID card 10 is kept in a pocket or the like, the electromagnetic field passes through the clothes inside and outside. Then, the high-frequency electromagnetic field generated by the fixed station 11 resonates with the LC resonance circuit 60 of the ID card 10. The energy obtained by the resonance circuit 60 is converted into DC power by the rectification circuit 63, and supplies power to each element in the ID card 10, such as the frequency dividing circuit 64 and the serial ROM 68. The clock synchronized with the resonance frequency extracted by the clock extracting circuit 62 is sent to the frequency dividing circuit 64, and the frequency-divided clock of the first clock generating circuit 65 is sent to the serial ROM 68 via the inverter circuit 67. Then, the ID code data as shown in FIG. When all the ID code data is read, the second clock generation circuit 66 outputs a signal divided by 128 and resets.

A check digit is added to the identification code data as needed. This serial ROM 6
8 in accordance with the identification code data output signal from
The transistor 69 is directly turned on and off to change the impedance.
The frequency at both ends of one coil 59 is AM-modulated.

More specifically, in FIG. 1 which shows an equivalent circuit of the fixed station 11 and the ID card 10, the coil 59 is not provided even if the ID card 10 is not present in the receiving area of the fixed station 11 or is located in the receiving area. In the case where there is no response due to the orthogonality of R and 71, the resonance frequency f of C0 and L0 of the fixed station 11 is expressed as f = 1 / {2π {(L0 · C0)}} and tuned to f = f0. The voltage V0 of the coil 59 becomes maximum. Usually, f0 = f.

Here, the transistor 6 of the ID card 10
When 9 is off, the resonance frequency f2 of the ID card 10 is f2 = 1 / {2π {(L1 · C1)}, and is tuned to f2 = f0.

When the transistor 69 is on, f2 = 1 / {2π {L1 (C1 + C2)}.

However, when the ID card 10 is in the reception area of the fixed station 11, if the transistor 69 is off, f2 = f0, so that a current i proportional to the strength of the electromagnetic field flows through the coil 71. . If the transistor 69 is on, then f2 ≠ f0, so the current i changes. This change in the current i changes the value of L0 of the coil 59 by the mutual induction action, and the voltage V0 changes. That is,
The ID card 10 includes a coil 59 of the fixed station 11 shown in FIG.
The high-frequency signal shown in (b) is converted to an AM signal as shown in FIG.
(Amplitude modulation). Note that, when the transistor 69 is on, tuning may be performed to f2 = f0, and when off, f2ｆf0.

(4) The voltage change as shown in FIG. 4D is detected by the envelope detection circuit 51 as shown in FIG. 4E, and the active filter circuit 52 detects the voltage change as shown in FIG. In this way, only necessary frequency components are taken out, converted into binary values by the comparator circuit 53 as shown in FIG.
Enter 4 The microcomputer 54 determines whether the input identification code data is registered.

(5) If registered, the fixed station number of the fixed station 11 is added to the identification code, and a signal is output from the microcomputer 54 to the fixed station central management unit 40. (6) The data input to the input / output unit of the fixed station central management unit 40 is output to the control circuit. (7) The controlled machine is controlled by the control signal from the control circuit.

[0022]

According to the present invention, the output of the serial ROM 68 is directly used as a drive source for turning on and off the transistor 69 of the modulation circuit 61. In contrast, the power consumption of the mobile station 10 is small, and a device having a small and simple circuit configuration can be provided.

[Brief description of the drawings]

FIG. 1 is an equivalent circuit diagram of a fixed station and a mobile station for explaining the principle of a mobile station identification device by radio of the present invention.

FIG. 2 is an electric circuit diagram of a mobile station (ID card) for implementing the wireless mobile station identification device of the present invention.

FIG. 3 is an electric circuit diagram of a fixed station for implementing the wireless mobile station identification device of the present invention.

FIG. 4 is an output waveform diagram of each part of FIGS. 2 and 3.

[Explanation of symbols]

Reference Signs List 10: mobile station (ID card), 11: fixed station, 40: fixed station central management unit, 50: LC resonance circuit, 51: envelope detection circuit, 52: active filter circuit, 53: comparator circuit, 54: microcomputer, 55 ... oscillation circuit, 56 ...
Switch circuit, 57: amplifier circuit, 58: booster circuit,
59: transmission / reception coil, 60: LC resonance circuit, 61: modulation circuit, 62: clock extraction circuit, 63: rectification circuit, 64
... frequency divider circuit, 65 ... first clock generation circuit, 66 ... second clock generation circuit, 67 ... inverter circuit, 68 ...
Serial ROM, 69: switch element composed of MOSFET, 70: capacitor, 71: transmitting / receiving coil, 72:
Capacitors.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-151183 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04B 5/00 H04B 1/59

Claims (1)

(57) [Claims] 1. An apparatus in which data is transmitted between a fixed station 11 and a mobile station 10 by a mutual guidance method so as to identify the mobile station 10, wherein the fixed station 10 has a resonance for forming a high-frequency electromagnetic field. The mobile station 10 comprising a circuit 50;
Are L and C that resonate in the reception area of the high-frequency electromagnetic field.
Are connected in parallel with each other, and a series circuit of a capacitor 70 and a transistor 69 is provided.
A modulation circuit 61 connected in parallel with the resonance circuit 60; a rectification circuit 63 for rectifying energy obtained by the LC resonance circuit 60 to supply power;
A clock extracting circuit 62 for extracting a clock from 0, a frequency dividing circuit 64 for dividing the frequency of the clock extracting circuit 62, and reading out the unique identification code data of the mobile station 10 from the output of the frequency dividing circuit 64 to read out the modulating circuit. And a serial ROM 68 for outputting a signal to the mobile station identification device 61. The mobile station identification device is characterized in that the output of the serial ROM 68 is used as a direct drive source for turning on and off the transistor 69 of the modulation circuit 61.