JP2516131B2 - Transceiver circuit for ID card system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter / receiver circuit for a wireless ID card system which discriminates a large number of child stations by a master station and communicates with each other in a wireless ID card system. The present invention relates to a transmission / reception circuit for a wireless ID card system which is effective for a battery type ID card in a required millimeter wave band.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram showing a basic configuration of a conventional transceiver circuit for a wireless ID card system. In FIG. 9, the ASK (Ampli) in a frequency band in which the carrier wave is relatively low is transmitted from the transmitter (TX) 1 on the master station side through the antenna 2.
tude Shift Keying: Amplitude displacement method)
Transmit the modulated wave to the slave station. The slave station receives this ASK modulated wave by the low gain antenna 3 and detects it by the detection circuit (DET) 4
It is configured to take out data by performing envelope detection with a diode. On the other hand, the slave station side fetches data from the carrier wave from the master station side into the phase modulator (PM MOD) 5, phase-modulates it by this, and transmits it again to the master station side. It is configured to be taken into the receiver (RX) 6 to obtain data.

[0003]

However, the above-mentioned conventional transceiver circuit for a wireless ID card system has the following problems. 1) Since signals are transmitted and received in a frequency band lower than the millimeter wave, it is easily affected by artificial noise, and it is difficult to sharpen the directivity of the antenna with the size of the card to reduce interference from others. 2) Further, since signals propagate well in a low frequency band, confidentiality is required, and it is necessary to prevent interference by changing the frequency when a large number of master stations are required. 3) Although the gain of the antenna can be increased in the millimeter wave band, there is a problem that the performance of the element used deteriorates.
That is, in such a low frequency band, ASK modulation and PM
(Phase Modulation) A PIN diode that can make the junction capacitance extremely small is used for modulation. However, the impedance change during conduction and non-conduction is reduced due to the influence of parasitic capacitance and inductive reactance.
There is a problem that the off ratio characteristic is significantly deteriorated. 4) There is a problem that the slave station cannot have a highly stable millimeter-wave band oscillator to reduce power consumption, and the gain of the system must be maximized. 5) The reception at the slave station side by the transmission signal from the master station side is the best from the viewpoint of easy envelope detection and low power consumption. However, since the detection sensitivity is low, it is necessary to suppress the power loss of the carrier as much as possible and input it to the detector. Specifically, the coupling loss to the modulated circuit for slave station transmission should be as small as possible, and this should be reduced. There is a problem that the transmission power to be generated must be compensated by increasing the modulation method and the reception sensitivity of the master station.

Therefore, the present invention is intended to eliminate the above-mentioned drawbacks of the conventional transmitting / receiving circuit for a wireless ID card system, and has low power consumption even in the millimeter wave band, and therefore the frequency can be effectively used. A simple and high-sensitivity ID that can increase transmission speed
It is an object to provide a transmitting / receiving circuit for a card system.

[0005]

A transmission / reception circuit for an ID card system according to the present invention, which has been proposed in order to achieve the above object, is a millimeter-wave band wireless ID for discriminating a large number of slave stations by a master station and communicating with each other. In the transceiver circuit for a card system, the slave station receives a master station carrier signal amplitude-modulated by the master station via an antenna, and an amplitude detection mode (reception
Mode) field effect transistor gate bias
Ttoshi, shift mode for transmitting a detection means for taking out the master station data envelope detection, the data to the master station from the slave station
Gate bar of the field effect transistor in (transmission mode)
Oscillation means for generating a low-frequency signal for generating a sideband shifted to a constant frequency from the master station carrier wave set to IAS, and mixing the low-frequency signal from the oscillating means with the master station carrier wave to transmit to the slave station. Mixer means for transmitting as a wave,
Modulating means for modulating the sideband with slave station data sent from the slave station to the master station, and a transmission / reception operation mode to the field effect transistor.
Gate of the field effect transistor to be subjected to the transmission is switched to the shift Tomo over de and the amplitude detection Namimo over de using static
Switch means for controlling the gate bias .

[0006]

In the present invention configured as described above, the wide band of the millimeter wave is used, the slave station transmits the data by shifting the frequency with respect to the carrier wave in order to prevent interference, and the master station transmits its own frequency. By using the transmitted wave as the local oscillation wave, the sideband of the received signal from the slave station is received by the super-heterodyne to realize high sensitivity. Further, since the shift frequency at the slave station is an intermediate frequency band of low frequency, phase modulation and frequency modulation can be easily performed, and the required S / N (C / N) of the master station can be made smaller than that of the ASK system. .

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing the basic configuration of a transmitting / receiving circuit for an ID card system according to the present invention. In the figure, reference numerals 7 to 16 denote constituent elements on the master station side, and 17 to 25 denote constituent elements on the slave station side.

In FIG. 1, 7 is a transmission oscillator for generating a transmission carrier on the master station side, 8 is an amplitude modulator for amplitude-modulating the transmission carrier from the transmission oscillator 7 by a modulation signal from a subcarrier modulator described later, and 9 is The demultiplexer 10 that transfers the master station transmission wave from the amplitude modulator 8 to the antenna described below and also transfers the reception wave from the slave station described later to the reception mixer described below via the antenna An antenna for transmitting the master station transmission wave from the wave splitter 9 to the slave station and receiving the slave station transmission wave from the slave station. Reference numeral 11 denotes the slave station reception wave from the duplexer 9 as a part of the master station transmission wave. A receiving mixer for mixing and providing an intermediate frequency signal, 12 is an intermediate frequency amplifier for amplifying the intermediate frequency signal from the receiving mixer 11, and 13 is an intermediate frequency for filtering only the intermediate frequency signal of the output of the intermediate frequency amplifier 12 ( I
F) Filter, 14 is a demodulator that demodulates the slave station data from the intermediate frequency signal from the IF filter 13, and 15 is the demodulated slave station data which is used for a predetermined purpose and which also generates a subcarrier modulation signal. A communication control circuit to be given to a subcarrier modulator shown below, and 16 is the subcarrier modulator.

Reference numeral 17 in FIG. 1 is an antenna for receiving a parent station received wave from the parent station, and 18 is a receiver for transmitting the received parent station received wave to an envelope detector shown below and a child from a transmission mixer described later. A coupler for transmitting the station transmission wave to the antenna 17, 1
Reference numeral 9 denotes an envelope detector for performing envelope detection on the received reception wave of the master station and extracting a subcarrier including the master station data.
0 is the baseband (B
B) Amplifier, 21 is a baseband (BB) filter that removes unnecessary component waves other than the amplified subcarrier, 22 is a demodulator that demodulates the master station data from the filtered signal, and 23 is the demodulated master station data. A communication control circuit 24, which is used for a predetermined purpose and sends slave station data to a shift oscillator shown below, receives the slave station data and shifts the slave station received wave from the master station carrier wave received by a certain low frequency. A shift oscillator for generating a low-frequency signal to be generated, and a transmission mixer 25 for transmitting a slave station reception wave, which is a mixture of the low-frequency signal from the shift oscillator 24 and the received carrier wave of the master station, to the coupler 18.

In the basic configuration as described above, on the master station side, the master station carrier wave f generated by the transmission oscillator 7 is generated.
The r is amplitude-modulated by the amplitude modulator 8, and the transmission wave ft1 is transmitted to the slave station side via the demultiplexer 9 and the antenna 10. On the slave station side, the received wave fr from this master station is received via the antenna 17 and the coupler 18, envelope-detected by the envelope detector 19, and then sub-subscribed via the BB amplifier 20 and the BB filter 21. Demodulator 2 that amplifies the carrier signal and limits the band
In 2, the master station data is demodulated, and the communication control circuit 23 provides it for a predetermined purpose.

On the other hand, when transmitting the data of the slave station from the slave station to the master station, the low frequency signal fs from the shift oscillator 24 and the received wave (not modulated) fr from the master station are transmitted to the transmission mixer 2.
5, and the transmission wave ft2 is transmitted to the master station via the coupler 18 and the antenna 17.

In this case, the power of the low frequency signal fs is set to be higher than that of the master station carrier fr. The slave station transmission wave ft2 from the slave station is ft2 = nfr ± mfs
(N and m are natural numbers), and when driving the low frequency signal fs, the slave station transmission wave ft2 is proportional to the level of the master station carrier wave fr. Further, in the master station, the slave station transmission wave ft2 from the slave station is received via the antenna 10 and the demultiplexer 9, converted into the intermediate frequency fi by the reception mixer 11, amplified by the intermediate frequency amplifier 12, and IF filtered. Filter with wave instrument 13,
The demodulator 14 extracts the slave station data. In the above equation, when m and n = 1, ft2 = fr ± fs
The intermediate frequency fi of the master station is fi = fs. Further, the slave station data is provided from the communication control circuit 23 in the form of modulating the shift oscillator 24, as will be described later.

Next, specific examples of the present invention will be described. Since the present invention is particularly configured in the slave station, an embodiment on the slave station side will be described below. Figure 2 shows FSK (Fre
guidance Shift Keying / ASK (Amplitude Shift K)
It is a circuit block diagram which shows one Example of this invention in the case of eyeing (amplitude displacement system) transmission. In the figure, a slave station reception wave fr from the master station is shown by an array antenna 26 (corresponding to the antenna 17 in FIG. 1) and an impedance matching circuit (MNW) 2
7, via the coupling capacitor 28, is input to the gate of the field effect transistor (FET) 29. FET2 of FIG.
As shown in bias characteristic curve of 9, have been applied gate bias voltage -Eg via a resistor 30 to the gate of FET 29, when the reception from the master station set to the biased position -Eg r of the detection mode And in this case F
Base station carrier f input from Eg · Id characteristics of ET29
r is subjected to envelope detection, and an amplifier 31 (BB amplifier 2 in FIG.
(Corresponding to 0) is extracted as ASK detection output through
It is sent to the BB filter 21 of FIG. In addition, FET29
Is applied with the drain bias + Ed via the resistor R1.

When transmitting from the child station to the parent station, FET
The gate of 29 is the transmission shift mode position -E in FIG.
The FET 29 is set to gt and the capacitance Cdg between the drain and gate, the capacitance Cgs between the source of the gate, and the inductive reactance of the inductor (L1) 32, the capacitor (C1) 33, and the variable capacitance diode 35.
Although the C oscillation circuit 34 (corresponding to the shift oscillator 24 in FIG. 1) is configured, the oscillation circuit described above may use a circuit having another configuration. Then, the reverse voltage is applied to the variable capacitance diode 35 of the oscillation circuit 34 via the resistor (R3) 36.
Oscillation output of the oscillation circuit 34 is frequency-modulated by causing applied is changed in sign pressurizing the pulse signal to a frequency modulation input terminal 37.

In this way, when transmitting from the slave station to the master station, the FET 29 and the oscillation circuit 34 including the FET 29 combine the coupler 18, the transmission mixer 25, and the shift oscillator 24 shown in FIG.
By applying a frequency modulation signal containing slave station data to the frequency modulation input terminal 37, a slave station transmission wave ft2 frequency-modulated by the slave station data can be obtained, and the array antenna 26 can be operated in the opposite manner to the case of reception. It is transmitted to the master station via.

FIG. 3 shows the entire embodiment of the FSK / ASK transmission shown in FIG. 2. The BB filter 21, demodulator 22 and communication control circuit 23 shown in FIG. 3 are the same as those shown in FIG. It has the same configuration as. The terminal 38 of the communication control circuit 23 receives the demodulated master station data from the demodulator 22, and the terminal 39 outputs the FM modulation signal as slave station data to the oscillator circuit 34.
And a terminal 40 is a terminal for switching the bias of the FET 29. When transmitting with ASK, the FET 29 from the bias switching terminal 40 of the communication control circuit 23.
This is performed by sending a pulse signal for switching Egt and Egr to the gate of, and the FM modulation signal terminal 39 at this time has no signal. In the case of the ASK system, the signal may not be given to the FM modulation signal terminal 39 and the transmission pulse may be superimposed on the gate bias. In that case, the terminal 37 of the resistor (R3) 36 on the communication control circuit 23 side is grounded.

FIG. 4 shows PSK (Phase Shift).
It is a circuit block diagram which shows one Example of this invention in the case of Keying (phase displacement system) transmission. In FIG. 4, the detection of the slave station reception wave fr from the master station is performed in the same manner as in the case of the above FSK / ASK transmission embodiment. That is, the slave station received wave fr is input to the FET 29 through the array antenna 26 and the impedance matching circuit 27. At the time of reception, the FET 29 is biased to -Egr in the figure and acts as a square wave detection, is amplified by the amplifier 31 via the capacitor (C1) 33, and is taken out as an ASK detection output. When transmitting the slave station data from the slave station to the master station, the low frequency signal fs is applied from the oscillator 41 (corresponding to the shift oscillator 24 in FIG. 1) to the phase modulator 42, and further the slave station is input from the phase modulation input terminal 43. A phase-modulated signal containing data is applied to the phase modulator 42, and its output is applied to the drain (D) of the FET 29 to transmit the slave-station received wave fr and the phase-modulated low-frequency signal fs to the slave station. Wave ft is array antenna 2
6 is transmitted to the master station. The PSK method has a problem that the circuit becomes complicated. Of course, the ASK method can be performed by using the phase modulator 42 as a switch and an amplitude modulator.

FIG. 5 shows the entire embodiment of the PSK transmission shown in FIG. 4 described above. The terminal 40 of the communication control circuit 23 sends a PM modulation signal as slave station data to the phase modulator 42. Terminals and terminals 44 are terminals for switching the bias of the FET 29.

FIG. 6 is a circuit configuration diagram showing an embodiment when the transmission modulation method is ASK / ASK. The receiving operation from the master station is similar to the case shown in the above-mentioned embodiment. At the time of transmission to the master station, + Ed is applied as the drain bias of the FET 29 from the ASK modulation signal terminal 45 of the communication control circuit 23 in the transmission mode, and a voltage equal to or lower than the bias voltage at which the oscillation circuit 34 stops oscillation in the ASK detection mode is applied. . Further, the bias voltage is switched from the bias switching terminal 46 of the communication control circuit 23 to the gate (G) of the FET 29 by a pulse signal between Egt and Egr.

FIG. 7 is a timing diagram showing an example of the operation waveforms of each part in the embodiment of FSK / ASK transmission of FIGS. 2 and 3 and the PSK transmission of FIGS. 5 and 6. In FIG. 7, a) is a clock signal indicating the time reference of the device operation,
b) is the bias waveform of the FET 29, c) is the ASK reception demodulation waveform in the ASK operation, d) is the transmission signal waveform from the slave station, e) is the gate bias waveform of the FET 29 in the ASK operation, and f) is 2 F SK The transmission frequency shift in the case of transmission, g) indicates the transmission phase shift in the case of 2PSK transmission.

FIG. 8 is a timing chart illustrating the operation waveforms of the respective parts in the case of the embodiment of ASK / ASK transmission of FIG. In FIG. 8, a) is a clock signal indicating a time reference of the device operation, b) is a reception demodulated signal of a carrier wave of the master station from the master station, c) is a bias of the FET 29 in the slave station reception and transmission operations, and d) is It is a waveform of the power supply of the FET 29 during ASK transmission.

[0022]

According to As is apparent the present invention the above, according to the present invention, electrostatic
Gate bias of field effect transistor and variable capacitance capacitor
Oscillator for generating a low frequency signal for controlling the reverse bias voltage of the sensor to shift data from the slave station to a fixed frequency for transmitting data from the slave station to the master station, and the low frequency signal to the master station. Mixer means for mixing with the carrier wave and sending out the sideband of the received master station carrier wave as the slave station transmission wave,
Modulating means for modulating the received carrier wave of the master station and the low-frequency oscillation wave by the slave station data from the slave station to the master station, and the gate bias of the field effect transistor for switching the transmission / reception operation mode between the ASK detection mode and the frequency conversion mode. Control
Transmission rate with by providing a switch means that, also constructed of low-power ID card system in the millimeter wave band with build a highly sensitive system with a simple circuit configuration, thus allowing effective use of the frequency There is an effect that can increase.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a transmitting / receiving circuit for an ID card system according to the present invention.

FIG. 2 is a circuit configuration diagram showing an embodiment of the present invention in the case of FSK / ASK transmission.

FIG. 3 is a circuit configuration diagram collectively showing an embodiment in the case of FSK / ASK transmission shown in FIG.

FIG. 4 is a circuit configuration diagram showing an embodiment of the present invention in the case of PSK transmission.

5 is a circuit configuration diagram showing an entire embodiment of the PSK transmission shown in FIG.

FIG. 6 is a circuit configuration diagram showing an embodiment when the transmission modulation method is ASK / ASK.

7 is a timing diagram illustrating operation waveforms of respective units in the FSK / ASK transmission embodiment of FIGS. 2 and 3 and the PSK transmission embodiment of FIGS. 5 and 6;

FIG. 8 is a timing chart exemplifying an operation waveform of each unit in the case of the ASK / ASK transmission example of FIG. 6;

FIG. 9 is a block diagram showing a basic configuration of a conventional transceiver circuit for a wireless ID card system.

[Explanation of symbols]

 17 Antenna 19 Envelope Detector 24 Shift Oscillator 25 Transmission Mixer

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-1-182780 (JP, A) JP-A 1-227553 (JP, A) JP-A 64-84175 (JP, A) JP-A 62- 294347 (JP, A) JP 55-114976 (JP, A) JP 62-283738 (JP, A) JP 63-302629 (JP, A) JP 63-121773 (JP, A) Japanese Patent Publication Sho 59-31018 (JP, B2)

Claims (2)

(57) [Claims] 1. A transmission / reception circuit for a millimeter-wave band wireless ID card system, which discriminates a large number of slave stations and mutually communicates with each other, wherein the slave station receives a master station carrier signal amplitude-modulated by the master station. Received via the antenna, amplitude detection mode (reception mode
Set to the gate bias of the field effect transistor
Then, a detection method for detecting the master station data by envelope detection, and a shift mode (sending mode) for transmitting the data from the slave station to the master station.
Signal mode) gate via of said field effect transistor
And oscillating means for generating a low frequency signal which is set to the scan generating sidebands shifted to a predetermined frequency from the master station carrier, mixing the low-frequency signal and the main station carrier from the oscillation means, and shifted sideband Mixer means for transmitting a master station carrier wave having a wave as a slave station transmission wave, and a transmission / reception operation mode for the amplitude of a side band wave of the slave station transmission wave shifted by the field effect transistor.
Subjected to transmission by switching Namimo over de and the shift Tomo over de
A transmitter / receiver circuit for an ID card system, comprising: a modulator for modulating gate bias of the field effect transistor, and a modulator for modulating with slave station data sent from the slave station to the master station. Wherein the ID card system for transmitting and receiving circuit according to claim 1 low-frequency signal to shift the master station carrier that is frequency modulated.