JPH08279082A - Alarm sound generating device - Google Patents

Abstract

PURPOSE: To securely prevent crime by generating alarm sounds by both a tag device attached to an article and a gate device installed at the entrance and exit of a store as to the alarm sound generating device for shoplifting prevention at the store, etc. CONSTITUTION: The prescribed electromagnetic wave outputted by the transmitting antenna 4 of the gate device A is received by the receiving antenna 5 of the tag device B and when a signal decision and burst signal separating circuit 7 judges that the signal is a prescribed signal, an alarm sound generating circuit 8 is placed in operation to generate the alarm sound and send an electromagnetic wave that is different in frequency from the signal sent by the gate device A and synchronized from the transmitting antenna 11. Further, this electromagnetic wave is received by the receiving antenna 12 of the gate device A and when a signal decision circuit 14 recognizes that the signal is sent from the tag device B, an alarm sound generating circuit 15 is placed in operation to generate the alarm sound even from the gate device.

Description

Detailed Description of the Invention

[0001]

[Industrial field of use]
The present invention relates to a warning sound generator used for theft prevention and the like.

[0002]

2. Description of the Related Art In recent years, self-sounding tag devices are often attached to products in order to prevent theft of products such as shoplifting in stores. In this type of security system, for example, a gate device that emits an electromagnetic wave is installed at the entrance / exit of a store, and when a product with a tag device attached passes through the gate device, the tag device itself detects a warning sound. Is to be emitted.

More specifically, the tag device is attached to a product (for example, a buttonhole is used for clothes) by using a wire, for example, and is placed on the sales floor together with the product. When the customer takes the product out of the store without completing the accounting process, the tag device passes through the gate device while attached to the product, and the tag device detects the electromagnetic wave of a specific frequency from the gate device. And a warning sound is generated.

When the customer forcibly removes the tag device from the product, the tag device detects that the wire has been removed, and the warning sound is also generated.

On the other hand, in the case of normal shopping, the clerk removes the tag device from the merchandise at the time of checkout, so that even if the customer carries the merchandise through the gate device, no warning sound is emitted. In this case, since there is a device that emits an electromagnetic wave so that the warning sound is not generated even if the wire is removed from the tag device at the checkout place, the warning sound is not emitted even if the clerk removes the wire from the tag device. .

Also, unlike the above, the radio wave generated by the gate device is caused to resonate on the tag device side, and the absorption of the radio wave is detected by the antenna of another gate device, and not on the tag device side but on the gate device side. It is also known to generate more warning sounds.

[0007]

In the case of a warning sound generating device in which the tag device itself generates a warning sound as described above, if the tag device itself is wrapped with cloth or the like, the warning sound cannot be heard by the surroundings. Therefore, it will not fulfill its role in crime prevention.

On the other hand, in the case of a warning sound generator that generates a warning sound on the side of the gate device, if the tag itself is forcibly removed from the product, only the product will pass through the gate device. You can't do it, and you can't play a role in crime prevention. Further, when a plurality of people pass through the gate device at the same time, the shoplifter cannot be identified even if a warning sound is generated from the gate device, that is, it is not known who took out the product with the tag device attached. There is.

[0009]

In order to solve the above problems, according to the present invention, a reference signal generating means for generating a reference signal and a reference signal transmitting means for transmitting a reference signal generated by the reference signal generating means by electromagnetic waves are provided. An electromagnetic wave generator having:
An electromagnetic wave receiving device having a reference signal receiving device for receiving a reference signal transmitted from the reference signal transmitting device of the electromagnetic wave generating device and a first warning sound producing device for producing an alarm sound only when the reference signal is received. An alarm sound generating device comprising: a response signal generating means for generating a response signal only when the reference signal receiving means receives a reference signal in the electromagnetic wave receiving device; and a response signal generated by the response signal generating means. And a response signal transmitting means for transmitting an electromagnetic wave, and in the electromagnetic wave generating device, a response signal receiving means for receiving a response signal transmitted by the response signal transmitting means of the electromagnetic wave receiving device, and the response signal receiving means for receiving the response signal. And a second warning sound generating means for generating a warning sound only when the response signal and the reference signal generated by the reference signal generating means are synchronized with each other. Is intended to St. provide the only warning sound generating device.

[0010]

With the above construction, the reference signal generated by the reference signal generating means of the electromagnetic wave generator is transmitted by the reference signal transmitting means. When this signal is received by the reference signal receiving means of the electromagnetic wave receiving device, the first warning sound generating means operates to generate a warning sound, and a response signal having a different frequency but synchronized with the reference signal is generated. It is generated by the means and is transmitted by the response signal transmitting means. Further, when this response signal is received by the response signal receiving means of the electromagnetic wave generating device, the second warning sound generating means operates to generate a warning sound.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

First, FIG. 1 is a circuit block diagram showing a configuration of an alarm sound generating apparatus of the present invention, and FIG. 2 shows signal waveforms in respective signal paths.

In FIG. 1, reference numeral A denotes a gate device. In the gate device A, reference numeral 1 denotes a signal generator as a first signal generating means, which generates a SIN wave (sine wave) signal having a frequency fa. (See waveform 1 in Figure 2).

Reference numeral 2 is a burst control signal generator. The SIN wave signal generated by the signal generator 1 is bursted by turning on / off the switch SW1 with a burst control signal (see waveform 2 in FIG. 2). Generate a signal (see waveform 3 in Figure 2).

The burst control signal generator 2 and the switch SW1 constitute a first signal converting means, and the signal generator 1, the burst control signal generator 2 and the switch SW1 are further provided.
And constitute the reference signal generating means.

Reference numeral 3 is a transmission signal amplifying circuit, which includes the signal generator 1, burst control signal generator 2 and switch SW.
The burst signal generated by 1 is amplified. 4 more
Is a transmitting antenna as a reference signal transmitting means, and radiates the transmitting signal amplified by the transmitting signal amplifier 3 into the air as an electromagnetic wave.

On the other hand, B shows the structure of the tag device,
In the tag device B, reference numeral 5 is a receiving antenna which is a reference signal receiving means, and receives the electromagnetic wave output from the transmitting antenna 4 of the gate device A when the tag device approaches the vicinity of the gate device. A reception signal amplifier 6 amplifies the reception signal received by the reception antenna 5.

Reference numeral 7 is a signal determination and burst signal separation circuit, which determines whether the received signal amplified by the received signal amplification circuit 6 is a prescribed burst signal, and if it is a prescribed burst signal, a burst portion. Is output as a square wave signal (see waveform 4 in FIG. 2) by envelope detection, and the warning sound generating circuit 8 in the subsequent stage is operated to generate a warning sound.

On the other hand, if an unspecified burst signal is input, no square wave is output, and the warning sound generating circuit 8 is not operated.

The signal judgment and burst signal separation circuit 7
And the warning sound generating circuit 8 constitutes a first warning sound generating means.

When the tag device B receives the prescribed burst signal, the signal judgment and burst signal separation circuit 7 operates not only the warning sound generation circuit 8 but also the signal generator 9 as the second signal generation means. As a result, the signal generator 9 generates the SIN wave signal having the frequency fb (see the waveform 5 in FIG. 2).

The SIN wave signal generated by the signal generator 9 is turned on / off by the square wave signal (see waveform 4 in FIG. 2) obtained by separating the burst signal by the signal judgment and burst signal separation circuit 7. By doing
Generate a burst signal (see waveform 6 in FIG. 2).

The signal judgment and burst signal separation circuit 7
The switch SW2 constitutes a second signal converting means, and the signal judging and burst signal separating circuit 7, the signal generator 9 and the switch SW2 constitute a response signal generating means.

Then, the burst signal is sent to the signal generator 9
The signal is amplified by a transmission signal amplifier circuit 10 in the subsequent stage, and further, an electromagnetic wave having a frequency different from that of the signal transmitted by the gate apparatus A and synchronized with the signal is transmitted to the air through a transmission antenna 11 which is a response signal transmitting means.

Further, in the gate device A, the electromagnetic wave emitted from the transmitting antenna 11 of the tag device B is received by the receiving antenna 12 which is the response signal receiving means, and the received signal is amplified by the received signal amplifying circuit 13.

Then, the received signal amplified by the received signal amplifying circuit 13 is compared with the output signal of the burst control signal generator 2 (see the waveform 2 in FIG. 2) by the signal judging circuit 14, and if synchronization is achieved, the tag is detected. Recognizing that the signal is a transmission signal from the device B, the alarm sound generation circuit 15 is operated to generate an alarm sound from the gate device.

The signal judging circuit 14 and the warning sound generating circuit 15 constitute a second warning sound generating means.

The operation of the warning sound generating device of the present invention is summarized as follows. (1) Activation of Tag Device by Electromagnetic Wave Output from Gate Device First, the signal generator 1 of the gate device A outputs S of frequency fa.
An IN wave signal is generated (see waveform 1 in FIG. 2), and this SIN wave signal is turned on by a burst control signal (see waveform 2 in FIG. 2) output from burst signal control signal generator 2 of 2.
A burst signal is generated by turning on / off (see waveform 3 in FIG. 2).

The generated burst signal is transmitted to the transmission signal amplifier 3
And is radiated into the air as an electromagnetic wave through the transmitting antenna 4.

Next, in the tag device B, the gate device A
The electromagnetic wave output from the transmitting antenna 4 is received by the receiving antenna 5, and the received signal is amplified by the received signal amplifying circuit 6.

Whether or not the amplified received signal is a specified burst signal is judged by the signal judgment and burst signal separation circuit 7, and if it is a specified burst signal, the burst portion is square wave signal by envelope detection (see FIG. 2). Waveform 4) of the above), and the warning sound generation circuit 8 in the subsequent stage is operated to generate the warning sound. (2) Activation of Gate Device by Electromagnetic Wave Output by Tag Device As described above, when the tag device B receives the prescribed burst signal, the signal determination and burst signal separation circuit 7 is provided with the warning sound generation circuit 8 Then, the signal generator 9 is operated to generate the SIN wave signal having the frequency fb (see the waveform 5 in FIG. 2).

A burst signal is generated by turning the SIN wave signal ON / OFF by the square wave signal (see waveform 4 in FIG. 2) obtained by separating the burst signal by the signal determination and burst signal separation circuit 7 (see FIG. 2). Waveform 6), the burst signal is amplified by the transmission signal amplifier circuit 10 and is transmitted through the transmission antenna 11 to the gate device A.
The electromagnetic wave having a frequency different from that of the signal to be transmitted and synchronized (that is, the period of the burst portion is the same as the waveform 2 in FIG. 2) is radiated into the air.

This electromagnetic wave is received by the receiving antenna 12 of the gate device A and is amplified by the received signal amplifying circuit 13.

The amplified received signal is sent to the signal judging circuit 14
The output signal of the burst control signal generator 2 is compared with that of the burst control signal generator 2 (see the waveform 2 in FIG. 2).
Is activated to generate a warning sound from the gate device.

On the other hand, when the signal received by the tag device B is a non-standard burst signal, the signal determination and burst signal separation circuit 7 does not operate the warning sound generation circuit 8 and the signal generator 9. Since the tag device B does not generate a warning sound and the tag device does not output an electromagnetic wave to the gate device, the gate device also does not generate a warning sound.

With this configuration, the reception signal when the electromagnetic wave from the gate device is received by the tag device and the reception signal when the electromagnetic wave from the tag device is received by the gate device are checked. Since it is operated, the operation is reliable and malfunctions are reduced.

Further, since the warning sound is generated from both the tag device and the gate device, only the above-mentioned conventional tag device generates the warning sound. The warning sound generation device and the gate device generate the warning sound. It is possible to provide a warning sound generating device that can compensate for the defect of the device, and improve the reliability in crime prevention.

[0038]

As described above in detail, according to the present invention, there are provided the reference signal generating means for generating the reference signal and the reference signal transmitting means for transmitting the reference signal generated by the reference signal generating means by the electromagnetic wave. An electromagnetic wave generating device, a reference signal receiving device for receiving a reference signal transmitted from a reference signal transmitting device of the electromagnetic wave generating device, and a first warning sound producing device for producing an alarm sound only when the reference signal is received. A warning sound generating device comprising an electromagnetic wave receiving device, wherein in the electromagnetic wave receiving device, a response signal generating device generates a response signal only when the reference signal receiving device receives the reference signal, and the response signal generating device. And a response signal transmitting means for transmitting a response signal generated by the electromagnetic wave, the response signal transmitting means of the electromagnetic wave receiving device in the electromagnetic wave generating device. A response signal receiving means for receiving a response signal to be transmitted, and a second warning sound for producing a warning sound only when the response signal received by the response signal receiving means and the reference signal generated by the reference signal generating means are synchronized. Since the generating means is provided, the alarm sound is generated from both the electromagnetic wave receiving device and the electromagnetic wave generating device to make crime prevention more reliable, and
It is possible to provide a warning sound generation device that is unlikely to cause a malfunction.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a configuration of an alarm sound generator of the present invention.

FIG. 2 is a diagram showing a signal waveform of the warning sound generator of the present invention.

[Explanation of symbols]

 1 signal generator (SIN wave of frequency fa) 2 burst control signal generator 3 transmission signal amplification circuit 4 transmission antenna 5 reception antenna 6 reception signal amplification circuit 7 signal judgment and burst signal separation circuit 8 warning sound generation circuit 9 signal generator (SIN wave of frequency fb) 10 transmission signal amplification circuit 11 transmission antenna 12 reception antenna 13 reception signal amplification circuit 14 signal determination circuit 15 warning sound generation circuit

Claims (3)

[Claims] 1. An electromagnetic wave generation device having a reference signal generation means for generating a reference signal and a reference signal transmission means for transmitting the reference signal generated by the reference signal generation means as an electromagnetic wave, and a reference signal transmission of the electromagnetic wave generation device. And a reference signal receiving means for receiving a reference signal transmitted from the means and a first warning sound generating means for generating a warning sound only when the reference signal is received, and an electromagnetic wave receiving device comprising: In the electromagnetic wave receiving device, a response signal generating unit that generates a response signal only when the reference signal receiving unit receives the reference signal, and a response signal transmitting unit that transmits the response signal generated by the response signal generating unit as an electromagnetic wave. And a response signal for receiving a response signal transmitted by the response signal transmitting means of the electromagnetic wave receiving device in the electromagnetic wave generating device. Signal receiving means and second warning sound generating means for generating a warning sound only when the response signal received by the response signal receiving means and the reference signal generated by the reference signal generating means are synchronized. Characteristic warning sound generator. 2. The reference signal generation means in the electromagnetic wave generation device converts the sine wave signal output from the first signal generation means into a burst signal and the sine wave signal output from the first signal generation means. The warning sound generating device according to claim 1, wherein the warning sound generating device comprises a first signal converting means. 3. A response signal generating means in the electromagnetic wave receiving device outputs a sine wave signal having a frequency different from that of the sine wave signal output from the first signal generating means in the reference signal generating means of the electromagnetic wave generating device. And a second signal converting means for converting the sine wave signal output from the second signal generating means into a burst signal synchronized with the reference signal output from the electromagnetic wave generating device. The warning sound generating device according to claim 1 or 2.