JPS62226078A - Identifying method for moving body - Google Patents

Abstract

PURPOSE:To reduce malfunction against external noise, and to improve the discriminating capacity by modulating it advance a radio wave irradiated from a transmitter, by a low frequency, demodulating a multiple wave radiated by a sensor, by a receiver, and fetching a signal of a modulation component. CONSTITUTION:A sensor 23 which has used a multiplier of a no-power source is attached to a moving body 22 such as a commodity of a store, a radio wave of a transmitting frequency f0 is irradiated to this sensor 23 from a transmitter 21, a multiple wave (an integer-fold of the frequency f0) radiated from the sensor 23 is detected by a receiver 24, and existence of the sensor 23 in a prescribed area is discriminated. Also, the radio wave of the transmitting frequency f0 is modulated in advance by a low frequency fa by the transmitter 21, and at the time of the multiple wave radiated from the sensor 23 has been detected by the receiver 24, this receiver 24 is demodulated and fetches the signal fa of the modulation component. Also, it is made to pass through a low frequency filter circuit 40 for making only the frequency fa pass through, and thereafter, only when a prescribed signal intensity has still been obtained, existence of the sensor 23 in the prescribed area is discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a typical block diagram of a transmitter used in a conventional mobile object identification method, and FIG. 2 is a typical block diagram of a receiver.

FIG. 3 is a typical block diagram of a transmitter used in the mobile object identification method of the present invention. At 3a in FIG. 3, the fundamental frequency fI is oscillated, and its power is supplied to the modulation circuit at 3b. On the other hand, 3c oscillates a low frequency fa, and this power is also supplied to the modulation circuit 3b. The modulation circuit frequency-modulates or phase-modulates the supplied f@ by fa,
3d multiplication amplifier circuit multiplies the transmission frequency up to Fs,
After amplifying the power to the required power using the power amplification circuit of e,
It is radiated into space as a transmitted wave from the transmitting antenna f.

If a sensor that operates without power exists within a certain range, a portion of the emitted transmission waves will be captured by the sensor,
An integer-multiplied wave is created inside the sensor and radiated into space.

A portion of the multiplied wave is captured by the receiver shown in FIG. First, it is guided to the receiving antenna 4a in Fig. 4, and
The low frequency fa is detected by a demodulation circuit 41 after passing through a frequency conversion amplifier circuit composed of h. The low frequency filter in 4j is a bandpass filter that only passes the low frequency fa, so the low frequency fa is supplied to the low frequency filter in 4j and can pass through it, but it cannot receive or receive radio waves such as external noise. When demodulated, the signal cannot pass through this filter unless it contains a modulation component of fa, which is why the method of the present invention has much better discrimination ability than the conventional method.

The low frequency fa that has passed through the filter of 4J is supplied to the alarm drive output circuit of 4, and if the signal strength is constant, the presence of a sensor in a certain area can be identified by mistake, and it can detect make, break, current, and voltage. , TTL signal, various digital signals, etc., and activates the next-stage W alarm generation circuit.

When the sensor is not within a certain area, the low frequency fa
Since it is not detected, the alarm generation circuit will not be activated.

In addition, alarm generation circuits specifically include announcements using buzzers, chimes, pulses, lights, tapes, or voice synthesis circuits, and in conjunction with them, alarms can be sent to security cameras, electric locks, building management systems, security systems, and computers. It is possible to report.

The above is the operating principle of the method of the present invention, which uses the transmitter shown in FIG. 1 and the receiver shown in FIG. Compared to the conventional method of identifying the presence of an object, the method of the present invention has extremely few malfunctions caused by external noise, and therefore the identification ability is greatly improved.

[Brief explanation of drawings]

FIG. 1 is a typical block diagram of a transmitter of a conventional mobile object identification device. FIG. 2 is a typical block diagram of a receiver of a conventional mobile object identification device. FIG. 3 is a representative block diagram of a transmitter of a mobile object identification device according to the present invention. FIG. 4 is a representative block diagram of a receiver of a mobile object identification device according to the present invention. la...high frequency oscillation circuit, lb...multiplying amplifier circuit, lc...power amplifier circuit, 1d...transmitting antenna, 2a...receiving antenna, 2b...high frequency amplifying circuit, 2c... 1st frequency conversion circuit, 2d... 1st local oscillation circuit, 2e... 1st intermediate frequency amplification circuit, 2f... 2nd frequency conversion circuit, 2g... 2nd local oscillation circuit, 2h...・Second intermediate frequency amplification circuit, 21...gJ alarm drive output circuit, 2j...alarm generation circuit, 3a...high frequency oscillation circuit, 3b...modulation circuit, 3c...low frequency oscillation circuit,
3d...multiplication amplifier circuit, 3e φ...power amplifier circuit, 3f...transmission antenna, 4a...reception antenna, 4b...high frequency amplifier circuit, 4c...first frequency conversion circuit, 4d... ...First local oscillation circuit, 4e...First intermediate frequency amplification circuit, 4f...Second frequency conversion circuit, 4g...Second local oscillation circuit, 4h...Second intermediate frequency amplification circuit, 41... Demodulation circuit, 4j... Low frequency filter,
4k...Alarm drive output circuit, 4λ...Alarm generation circuit. -Figure 2- -Figure 4 - Procedural Amendment (Written) June 27, 1985 Patent Application No. 070581 2, Name of Invention Mobile Object Identification Method 3, Relationship with the Amendment Person Case Patent applicant address: 6-2-18 Shimorenjaku, Mitaka City, Tokyo Name
Japan High Frequency Co., Ltd. Representative: Akira Ogawa 4, Agent address: 1-5-3-6, Hirakawa-cho, Chiyoda-ku, Tokyo, Inventor column of application subject to amendment, full text of specification and drawing 7, Attachment to contents of amendment As per 8, list of attached documents (1) Amended fIY form (2) Statement of reasons (3) Deed of transfer
(4) Certificate of residence (5) Certificate of non-residence (6) Letter of identification (7)
)Drawing Specification (1) 1. Name of the invention Moving object identification method 2. Claims (1) A sensor using a power-free multiplier is attached to the moving object, and the transmitter transmits the transmission frequency to the sensor. In the device that identifies the presence of the sensor within a certain area by emitting radio waves of f0 and detecting a multiplied wave of an integral multiple of f6 emitted by the sensor with a receiver, Transmission frequency f at frequency fa. The radio wave is modulated, and when the receiver detects the multiplied wave emitted by the sensor, the receiver demodulates and extracts the modulated component signal, signal fa, and further filters the signal fa to pass only the frequency fa. A mobile object identification method that identifies the presence of a sensor within a certain area only when a certain signal strength is still obtained after passing through the sensor. (2) The mobile object identification method according to claim 1, wherein the modulation circuit of the transmitter performs frequency modulation. (3) The mobile object identification method according to claim 1, wherein the modulation circuit of the transmitter performs phase modulation. 3. Detailed Description of the Invention "Field of Industrial Application" The present invention irradiates a power source of a certain reference frequency from a transmitter to a sensor using a power-free multiplier attached to a moving object such as a store product. The present invention relates to a moving object identification method in which the presence of a sensor within a certain area is identified by detecting a wave emitted by a sensor that is a multiple of an integral multiple of its reference frequency. "Prior Art" In recent years, damage caused by shoplifting in department stores, supermarkets, etc. has been increasing, and various countermeasures have been considered, and recently, a shoplifting monitoring device that applies electronic technology has appeared. In this system, a sensor is attached to the product in advance and is normally removed at the time of checkout, but if the product is taken out with the sensor still attached, a monitoring device installed at the entrance will detect this and issue an alarm. . However, the transmitter (1) and receiver (2) of a conventional mobile object identification device are shown in FIG. In this figure 2, in the transmitter (1), the high frequency signal oscillated by the high frequency oscillation circuit (3) is multiplied to the transmission frequency by the multiplier amplifier circuit (4), and then amplified to the required power by the power amplifier circuit (5). , is radiated into space as a transmission wave by a transmission antenna (6). The radiated radio waves are captured by an unpowered sensor (8) attached to a moving body (7) such as a product, where integral multiples of waves are created and radiated into space again. Radio waves from this sensor (8) are captured by a receiving antenna (9) of a receiver (2). Then, the high frequency signal is amplified by the high frequency amplifier circuit (10), and the first intermediate frequency signal is obtained by the first local oscillation circuit (11) and the first frequency conversion circuit (12), which is then amplified by the first intermediate frequency amplifier circuit. After being amplified in (step 3), a second intermediate frequency signal is obtained by the second local oscillation circuit (14) and the second intermediate frequency conversion circuit (15), which is then transferred to the second intermediate frequency amplification circuit (16).
The signal is amplified by the alarm drive output circuit (17) and then activates the alarm generation circuit (18). ``Problems to be Solved by the Invention'' However, in the conventional method, a receiver receives the multiplied wave emitted by the sensor, and the presence of the sensor is identified based on the signal strength of the multiplied wave itself. There was a problem that it was easy to malfunction. "Means for Solving the Problems" The present invention was made to solve the above-mentioned problems.A sensor using a power-free multiplier is attached to a moving object, and a transmitter is connected to the sensor. from the transmission frequency f. The sensor emits radio waves f. In the device in which a receiver detects a multiplied wave of an integral multiple of , and identifies the presence of the sensor within a certain area, the transmitter modulates a radio wave of a transmission frequency f0 with a low frequency fa in advance. , when the receiver detects the multiplied wave emitted by the sensor, the receiver demodulates the signal fa of the modulation component, and after passing it through a filter that only passes the frequency fa, the signal strength remains constant. This is a moving object identification method that identifies the presence of a sensor within a certain area only when . ``Example'' An example of the present invention will be described below with reference to FIG. (21) is a transmitter used in the method of the present invention; (22)
indicates a moving object, (23) a sensor, and (24) a receiver. In the transmitter (21), (25) is the fundamental frequency f
(26) is a modulation circuit for frequency modulation or phase modulation; (27) is a high-frequency oscillation circuit that oscillates a high-frequency signal;
) is a low frequency oscillation circuit that oscillates a low frequency signal of low frequency fa, (28) is a multiplier amplifier circuit, (29) is a power amplifier circuit, and (30) is a transmitting antenna. In the receiver (24), (31) is a receiving antenna. (32) is a high frequency amplification circuit, (33) is a first frequency conversion circuit, (34) is a first local oscillation circuit, (35) is a first intermediate frequency amplification circuit, (36) is a second frequency conversion circuit, ( 3
7) is the second local oscillation circuit, (38) is the second intermediate frequency amplification circuit, (39) is the demodulation circuit, (40) is the low frequency filter circuit, (41) is the alarm drive output circuit, and (42) is the alarm This is a generation circuit. In the circuit configuration as described above, a high frequency signal having a fundamental frequency f0 is oscillated in the high frequency oscillation circuit (25) of the transmitter (21), and its power is supplied to the modulation circuit (26). On the other hand, the low frequency oscillation circuit (27) oscillates a low frequency fa signal and also supplies this power to the modulation circuit (26). This modulation circuit (26) converts the supplied fo into fa.
Frequency modulation or phase modulation is performed using a multiplication amplifier circuit (
28) to the transmission frequency f0, and the power amplifier circuit (2
9) to the required power, the transmitting antenna (
30), it is radiated into space as a transmission wave. If there is a sensor (23) that operates without power supply within a certain range, a part of the emitted transmission wave will be transmitted to the sensor (23).
is captured by the sensor (23), an integer-multiplied wave is created, and the wave is radiated into space. A part of the multiplied wave is transmitted to the receiving antenna (31) of the receiver (24).
), which first obtains a first intermediate frequency signal in a first local oscillation circuit (34) and a first frequency conversion circuit (33), which is amplified in a first intermediate frequency amplification circuit (35), Furthermore, a second intermediate frequency signal is obtained by a second local oscillation circuit (37) and a second frequency conversion circuit (36), and this is amplified by a second intermediate frequency amplification circuit (38). Furthermore, the demodulation circuit (3
9), the low frequency fa is detected. Here, since the low frequency filter circuit (40) is a bandpass type filter that only passes the low frequency fa, the low frequency fa is supplied to the low frequency filter circuit (40) and can pass through it. When receiving and demodulating radio waves such as external noise, fa
The signal cannot pass through this low frequency filter circuit (40) unless it contains a modulated component. The low frequency fa passed through this low frequency filter circuit (40)
is supplied to the alarm drive output circuit (41), and if the signal strength is constant, the sensor (23
) is identified, make, break, current, voltage,
It is output as a TTL signal, various digital signals, etc., and activates the primary stage alarm generation circuit (42). When the sensor (23) is not present within a certain area, the low frequency fa is not detected, so the alarm generating circuit (42) is not activated. The alarm generation circuit (42) specifically includes a buzzer, a chime, a bell, a light, a tape, an announcement using a voice synthesis circuit, and the like. In conjunction, it is possible to report to security cameras, electric locks, building management systems, security systems, computers, etc. "Effects of the Invention" Since the present invention employs the method described above, unlike the conventional method,
Compared to a method of receiving a multiplied wave emitted by a sensor and identifying the presence of the sensor based on the signal strength of the multiplied wave itself, this method has extremely low malfunction due to external noise and the like, and therefore the identification ability is greatly improved. 4. Brief description of the drawings Fig. 1 is a block diagram of a transmitter, sensor, and receiver used in the mobile object identification method according to the present invention, and Fig. 2 is a block diagram of a transmitter, sensor, and receiver of a conventional mobile object identification device. This is the block diagram of (1)(21)...Transmitter, (2)(24)...
Receiver, (3) (25)...High frequency oscillation circuit, (4)
(28)...multiplying amplifier circuit, (5) (29)...
・Power amplifier circuit, (6) (30)...transmission antenna,
(9)(31)...Receiving antenna, (7)...Mobile object, (10)(32)...High frequency amplification circuit, (12)
(33)...first frequency conversion circuit, (11) (34
)...First local oscillation circuit, (13)(35)...First intermediate frequency amplification circuit, (15)(36)...Second frequency conversion circuit, (14) (37)... Second local oscillation circuit, (16) (38)... Second intermediate frequency amplification circuit, (17) (41)... Alarm drive output circuit, (18
) (42)...Alarm generation circuit, (26)...Modulation circuit, (27)...Low frequency oscillation circuit, (39)...
Demodulation circuit, (40)...low frequency filter circuit.

Claims (1)

[Claims] (1) A sensor using a power-free multiplier attached to a moving body is irradiated with radio waves with a transmission frequency of F_0, and the sensor emits a multiplication wave that is an integral multiple of F_0 and detects it within a certain area. In a mobile object identification device that identifies the presence of a sensor, in order to improve its identification ability, a radio wave with a transmission frequency F_0 is frequency-modulated or phase-modulated with a low frequency fa in advance, and the multiplied wave emitted by the sensor is detected. When this happens, the presence of a sensor within a certain area can be identified only when a certain signal strength is obtained after demodulating and extracting the modulated component signal fa, and passing it through a filter that passes only the frequency fa. A mobile object identification method.