JPH06260964A - Radio data carrier device - Google Patents

Abstract

PURPOSE:To provide a device with high security in which code information can not be read from a transponder without a normal interrogator. CONSTITUTION:This device is equipped with a tuning circuit 13 which interrupts the passage of signal components which are not the first frequency components, frequency shift detecting part 14, and gate 15. Then, a state that 'a signal being received is the first frequency, and the received frequency is stable without any frequency shift' is detected in order to control a second transmitter 8 being a transmitting means, and the radio wave of the second frequency modulated by information is transmitted by the transmitting means. When the signal being received is not the first frequency, or the received frequency is unstable with the frequency shift even when the signal is the first frequency, transmission prohibition is instructed to the transmitting means, and the radio wave can not be transmitted to an interrogator 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless data carrier device.

[0002]

2. Description of the Related Art A conventional wireless data carrier device is shown in FIG.
It is configured as shown in. The wireless data carrier device is an interrogator (interrogator, interrogator).
r) 1 and transponder (transponder, Trans Pon)
der) 2. The interrogator 1 has a transmitting antenna 3 and a receiving antenna 4, receives the radio wave of the first frequency f1 from the interrogator 1, and receives a second frequency f2 different from the first frequency f1.
The transponder 2 for transmitting is provided with a receiving antenna 5 and a transmitting antenna 6.

The signal of the first frequency f1 generated from the first oscillator 7 of the interrogator 1 is transmitted from the transmitting antenna 3. This signal is received by the receiving antenna 5 of the transponder 2. From the receiving antenna 5 to the second transmitter 8
When the signal is input to the second oscillator 8, the second oscillator 8 generates a signal of the second frequency f2 and supplies it to the modulator 9. The code information N peculiar to the transponder 2 is written in the code storage unit 10, and the modulator 9 modulates the signal of the second frequency f2 with the code information read from the code storage unit 10 and transmits it. It is transmitted from the antenna 6. The interrogator 1 receives the second frequency f2 from the transponder 2.
Is received via the receiving antenna 4, demodulated into the original code information N by the demodulator 11, and the code information of the transponder 2 is read by the interrogator 1. Reference numeral 12 is a battery that supplies power required by the transponder 2.

Such a wireless data carrier device is
The interrogator 1 is installed on the fixed side, and the transponder 2
Is installed in the moving body, the interrogator 1 can identify the transponder 2 by reading the code information from the transponder 2 without contacting the transponder 2.

[0005]

In such a conventional configuration, since the second oscillator 8 operates by inputting a radio wave of an appropriate frequency to the transponder 2, the transponder 2 is qualified to ask a question. Interrogator 1
Even if not, the code information N written in the code storage unit 10 can be illegally read by receiving and demodulating the radio wave transmitted from the transmitting antenna 6. This is not preferable from the viewpoint of preventing imitation of the transponder 2 and has low security.

An object of the present invention is to provide a wireless data carrier device which can read code information from a transponder 2 only by a regular interrogator 1.

[0007]

According to another aspect of the present invention, there is provided an interrogator for transmitting a radio wave of a first frequency as a transmission medium, and a self-coded information at a frequency different from the first frequency. A wireless data carrier device configured with a transponder that transmits a modulated radio wave of the second frequency, and that receives and demodulates the radio wave of the second frequency transmitted from the transponder side on the interrogator side to read the code information. In the transponder, a tuning circuit connected to the receiving antenna to block passage of a signal component other than the first frequency component, and a frequency shift detection connected to the receiving antenna to detect the presence or absence of frequency deviation of the signal being received. Section, the output of the tuning circuit and the output of the frequency deviation detection section, and detects a state where there is a first frequency component and there is no frequency deviation. A gate which is characterized in that a transmission means for prohibiting transmission of radio waves of the second frequency at the output of the gate.

According to a second aspect of the present invention, there is provided a wireless data carrier device according to the first aspect, wherein the gate has a first frequency component and the frequency shift is between the gate and the transmitting means. It is characterized in that a timer for instructing the transmission means to prohibit the transmission of the radio wave of the second frequency is provided for a specified time after detecting the state where

[0009]

According to the structure of the present invention, since the tuning circuit for blocking the passage of the signal component other than the first frequency component, the frequency deviation detecting section and the gate are provided to control the transmitting means, the signal being received is When it is detected that the reception frequency is stable at the frequency of 1 and there is no frequency deviation, the transmission means transmits the radio wave of the second frequency modulated by the information. If the signal being received is not the first frequency, or if the received frequency is unstable due to frequency deviation even if the signal has the first frequency, the transmission means is instructed to prohibit transmission.

According to the second aspect of the present invention, it is detected that the signal being received has the first frequency and the received frequency is stable without frequency deviation, and the transmitting means is modulated with information. The radio wave of the second frequency is transmitted. The timer for instructing the transmission means to prohibit transmission does not operate in this case. Even if the signal being received has the first frequency, if the received frequency is unstable due to frequency deviation, the timer operates and instructs the transmission means to prohibit transmission for a specified time, and within this specified time. Will not accept any question requests.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Each embodiment of the present invention will be described below with reference to FIGS. It should be noted that components having the same functions as those of the conventional example shown in FIG.

FIG. 1 shows a first embodiment of a wireless data carrier device according to the present invention, in which a tuning circuit 13 and a frequency shift detector 14 are provided between a receiving antenna 5 of a transponder 2 and a second oscillator 8. The difference from the conventional example shown in FIG. 3 is that a discrimination circuit 16 including a gate 15 is interposed.

The tuning circuit 13 is configured to pass a signal component of the first frequency f1 and block a signal component other than the first frequency f1. The frequency shift detection unit 14 is configured to detect whether the frequency being received is stable over time. The gate 15 detects that the signal being received has the first frequency f1 and that the reception frequency is stable because there is no frequency deviation and the output state is inverted (for example, from "L" to "H"). The output state is not inverted if the signal being received is not the first frequency f1 or if the signal having the first frequency f1 has a frequency deviation and the reception frequency is unstable. ("L"
Maintain state). When the second oscillator 8 detects the state in which the output of the gate 15 is inverted to "H", the second frequency f2
Signal is generated and supplied to the modulator 9. The modulator 9 modulates the signal of the second frequency f2 with the code information N read from the code storage unit 10, and the signal is transmitted from the transmission antenna 6. The interrogator 1 receives the radio wave of the second frequency f2 from the transponder 2 via the receiving antenna 4, demodulates it to the original code information in the demodulator 11, and the code information N of the transponder is interrogator 1.
Read by. When the state where the output of the gate 15 is "L" is detected, the transmitting operation of the second oscillator 8 is prohibited and the radio wave is not radiated from the transmitting antenna 6 to the interrogator 1.

With this configuration, even if an outsider who does not know the regular frequency (f1) of the interrogator 1 transmits a radio wave and asks the transponder 2, the code information cannot be read. Even if the frequency is the regular frequency (f1), if the state of the regular frequency (f1) is not stable, the second oscillator 8 is prohibited from transmitting and the radio wave is not radiated from the transmitting antenna 6 to the interrogator 1. Even if the outsider generates a sweep signal whose frequency changes over a wide band with the lapse of time in an attempt to find the regular frequency (f1), even if the regular frequency (f1) signal coincides with the sweep signal. Since the signal is swept at a predetermined speed and the frequency is unstable, the frequency deviation detection unit 14 detects this state and prohibits the operation of the second oscillator 8. Therefore, higher security is ensured. Can be secured.

FIG. 2 shows a second embodiment. In this second embodiment, a timer 17 is interposed between the gate 15 and the second oscillator 8 of the first embodiment, and the timer 17 starts timekeeping in the following state, The second oscillator 8 stops operating for the timed time.

Even if the signal of the normal frequency (f1) temporarily matches, if the signal is swept at a predetermined speed, one of the gates 18 at the time of matching the signal of the normal frequency (f1). The input is temporarily inverted (for example, inverted from “L” to “H”), and the other input of the gate 18 inverts the output of the frequency deviation detection unit 14 by the knot circuit 19 to change from “L” to “H”. ", So that the output of the gate 18 is inverted and the timer 17 starts counting time.

When the operation of the second oscillator 8 is controlled by the output of the timer 17 as described above, the operation of the second oscillator 8 is stopped for a specified time of the timer 17 when an incorrect inquiry signal is received. Then, the receiving antenna 5 receives the signal whose frequency is swept.
The fraudulent act of searching for the regular inquiry frequency (f1) can be disturbed, and the security is further improved. Further, in this embodiment, when a fraudulent act occurs, the buzzer 19 can be sounded to notify.

[0018]

According to the wireless data carrier device of the present invention, the transmitting means is controlled by providing the tuning circuit for blocking the passage of the signal component other than the first frequency component, the frequency deviation detecting section and the gate. Therefore, the received signal is the first
The frequency (f1) is detected and the reception frequency is stable with no frequency deviation, and the transmission means transmits the radio wave of the second frequency modulated with the information. If the signal being received is not the first frequency (f1), or even if the signal has the first frequency (f1), there is frequency deviation and the reception frequency is unstable. Therefore, even if an outsider tries to find the regular frequency (f1) of the interrogator by transmitting a sweep signal, the code information cannot be read out, so that high security can be secured.

According to the wireless data carrier device of the second aspect, since the timer is provided between the gate and the transmitting means, even if the signal being received is the first frequency (f1), the frequency deviation is caused. If the reception frequency is unstable, the timer operates to instruct the transmission means to prohibit transmission for a specified time, and no question request is accepted within this specified time, so the signal swept by the frequency is changed. It is possible to disturb a fraudulent act of searching for a regular inquiry frequency (f1) by giving it, and the security is further improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment of a wireless data carrier device of the present invention.

FIG. 2 is a configuration diagram of a second embodiment.

FIG. 3 is a configuration diagram of a conventional wireless data carrier device.

[Explanation of symbols]

 1 interrogator 2 transponder 7 first oscillator 8 second oscillator 9 modulator 10 code storage unit 13 tuning circuit 14 frequency deviation detection unit 15 gate f1 first frequency f2 second frequency N code information

Claims (2)

[Claims] 1. An interrogator that transmits a radio wave of a first frequency as a transmission medium, and a transponder that transmits a radio wave of a second frequency modulated with its own code information at a frequency different from the first frequency. A wireless data carrier device for reading the code information by receiving and demodulating the radio wave of the second frequency transmitted from the transponder side on the interrogator side, wherein the transponder has a first frequency component connected to a receiving antenna. A tuning circuit that blocks the passage of non-signal components, a frequency deviation detection unit that is connected to the receiving antenna and detects the presence or absence of frequency deviation of the signal being received, and an output of the tuning circuit and the output of the frequency deviation detection unit. A gate that is connected and detects a state that has a first frequency component and that has no frequency deviation, and an output of the gate that outputs the radio wave of the second frequency. A wireless data carrier device provided with transmitting means for inhibiting transmission. 2. A first gate is provided between the gate and the transmitting means.
2. The wireless data according to claim 1, further comprising a timer for instructing the transmitting means to prohibit the transmission of the radio wave of the second frequency for a specified time after detecting a state in which there is a frequency component and a frequency deviation. Carrier device.