JPS63291195A - Crime preventing device - Google Patents

Abstract

PURPOSE:To omit many invasion sensors by adjusting respective arrangement positions of transmitting and receiving antennas so that the receiving antenna is positioned on a fading generating position of radio waves radiated from the transmitting antenna into a warning area and deciding the existence of an invader in accordance with the change of a propagating state of the radio wave between the transmitting part and receiving part. CONSTITUTION:In case of setting up the transmitting and receiving antennas 2, 3, the fading generating position of radio waves radiated from the transmitting antenna 2 into the warning area A is checked while observing the lighting state of light emitting diodes L1-L4 in a receiving level display part 27 of the receiving part 3. The receiving antenna 3 is arranged on the fading generating position and the level of a transmission signal is set up so that the receiving output level of the receiving part 4 is dropped lower than a prescribed level. When an invader X enters into the warning area A, the propagating state of radio waves is changed and the fading generating position is changed. The change is detected by a level deciding part 26 in the receiving part 4 and an informing means 5 is driven.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 1] The present invention relates to a security device for detecting an intruder into a room or a house.

[Background Art 1 Conventionally, this type of crime prevention device for detecting intruders into a room or a house has been constructed by placing an intrusion sensor at each doorway, window, or other place where people can enter and exit. Some devices operate a notification means by determining whether or not there is an intrusion based on sensor output. However, in such a conventional example, a large number of intrusion sensors are required, which makes the installation troublesome and increases the cost.In addition, the signal processing of the sensor output becomes complicated. , there was a problem of higher costs.

[Objective of the Invention 1 The present invention has been made in view of the above points, and its purpose is to provide a crime prevention device that does not require a large number of intrusion sensors, is easy to install, and is inexpensive. It is in.

[Disclosure of the Invention] (Structure) The present invention includes a transmitter that outputs a transmission signal in an extremely high frequency band or an extremely high frequency band, one or more transmitting antennas that are excited by the transmitted signal, and It consists of a receiving antenna that receives radio waves, and a receiving section that processes the output of the receiving antenna and controls the notification means. At the same time, the positions of the transmitting and receiving antennas are set at i1+ so that the receiving antenna is located at the location where the radio waves radiated from the transmitting antenna into the warning area occur. By forming the receiving part so that the notification means is activated when the received radio wave output exceeds a preset level, there is no need for a large number of intrusion sensors, and the construction is easy and low cost. It provides a security device.

(Embodiment 1) Figures 1 to 4 show an embodiment of the present invention, in the very high frequency band (V) (F, UHF,...
), one or more transmitting antennas 2 excited by the transmitting signal, a receiving antenna 3 receiving radio waves radiated from the transmitting antenna 2, and a receiving antenna 3. It is composed of a receiving section 4 that processes the output into signals and controls the notification means 5, and a transmitting antenna 2 and a receiving antenna 3 are arranged at appropriate intervals at key points within a warning area A such as indoors or inside a house. , transmit and receive antennas 2 and 3 so that the receiving antenna 3 is located at the location where the radio waves radiated from the transmitting antenna 2 into the warning area A are generated.
The receiving section 4 is arranged so that the notifying means 5 is operated when the reception output of the radio wave exceeds a preset level. Here, in the embodiment, the transmitting section 1 includes an oscillating section 10 and a multiplier section 1.
1, a signal oscillation section 12, a modulation section 13, an attenuator 14, and a power amplification g15.
The oscillation signal generated at 0 is converted to a high frequency by the multiplier 11 to form a carrier wave of a predetermined frequency, and the modulator 13 modulates this carrier wave with the modulation signal generated by the signal oscillator 12. A transmission signal is formed using the attenuator 14 and a transmission signal of a predetermined level is supplied to the transmission antenna 2 via an upstream power amplifying section 15.

Further, the receiving section 3 includes a filter 20, a local oscillator section 21, a mixing section 22, an intermediate frequency amplifying section 23, a reproducing i1 section 24,
It is formed by a low frequency amplification section 25, a level determination section 26, and a received level display section 27, and receives and demodulates the signal of a predetermined frequency extracted by the filter 20 by a so-called superhetero gain type receiving circuit, After the demodulated signal is low-frequency amplified, the level determination unit 26 determines the signal level, and intrusion is detected when the received output level of the radio wave output from the low-frequency amplification unit 25 exceeds a predetermined level. The notification means 5 is operated by outputting a signal. Further, in the embodiment, a reception level display section 27 is provided that displays the reception output level in stages, and the reception level display section 27 includes a rectification and smoothing circuit including a diode D0, a resistor R8, and a capacitor C0, voltage dividing resistors R, , which divide the signal level voltage output from the circuit 30;
-R1, voltage dividing resistors R21 to R25 that divide the power supply voltage Vcc to generate a reference voltage, and comparators CP1 to
CP, driving transistors Q and -Q, and light emitting diodes L1 to L4, and displays the level of the signal output from the low frequency amplification section 25 in four stages. In the embodiment, when the radio waves received by the receiving antenna 3 are weak, the light emitting diode L4 lights up first, and when a signal with a level several dB higher than that signal is received, the light emitting diode L lights up, A few more d
B When a high-level radio wave is received, light-emitting diode L2 lights up, and when a signal with a level several dB higher is received, light-emitting diode L lights up, and light-emitting diode L, ~L4 The electric field strength distribution can be easily checked based on the lighting state of the transmitter 1, the receiving antenna 3 can be easily installed at the location where the transmission occurs, and the level of the transmitting signal from the transmitter 1 can be easily adjusted.

The operation of the embodiment will be described below. Now, the transmitting antenna 2 is excited by a transmission signal in the very short wave band to the extremely short wave band.
From indoors, like inside a house! 1 Radio waves emitted within warning area A propagate by being repeatedly reflected by walls, floors, ceilings, house decorations, etc., and the electric field strength within warning area A is composed of multiple reflected waves with different phases. Figure 2 (,
) The strength and weakness shown in ) are occurring. In particular, the phenomenon in which the electric field strength weakens is generally referred to as 7-enonging, and in the present invention, this 7-enong phenomenon is actively utilized to determine changes in the situation within the alert*RA and detect intruders. It is designed to perform detection. First, when installing the transmitting antenna 2 and the receiving antenna 3, the transmitting antenna 2
The light emitting diode L of the reception level display section 27 of the reception section 3 indicates the location where the radio waves radiated from the 7-waves into the warning area A are generated.

-L, the receiving antenna 3 is placed at the position where fading occurs, and the transmitting signal level is set so that the receiving output level of the receiving section 4 is lower than a predetermined level. In this state, if there is no change in the warning area A, the reception output level of the radio waves received by the reception antenna 3 placed at the location where the construction occurs remains low, and the intrusion detection signal is is not output and the notification means 5 does not operate.Next, when intruder X enters vVa area A, the propagation state of radio waves changes and
Since the location where the machining occurs changes, the received output level of the radio waves received by the receiving antenna 3 increases. In the receiving section 4, this increase in the received output level is detected by the level determining section 26.
The device detects the intrusion, outputs an intrusion detection signal, operates the notification means 5, and provides notification using an alarm buzzer, alarm lamp, etc., or via a telephone line.

For example, when the electric field strength distribution in a state where no intruder X is in the security area A is as shown in FIG. The electric field strength at this point P is extremely low. Therefore, the reception output level of the radio wave received by the reception antenna 3 is smaller than the determination level vth set in the level determination section 26 of the reception section 4, and the intrusion detection signal is output from the reception section 4. Therefore, the notification means 5 does not operate.

Next, the electric field strength distribution when an intruder
7 - The song generation position moves to a place other than point P, and the electric field strength at point P increases significantly, and the reception output level of the radio wave by receiving antenna 3 becomes higher than the judgment level vth, so When the intrusion detection signal is output, the notification means 5 operates to notify that the intruder A is present.

[Effects of the Invention 1] As described above, the present invention includes a transmitter that outputs a transmission signal in a very high frequency band or an extreme IR shortwave band, one or more transmitting antennas that are excited by the transmitted signal, and It consists of a receiving antenna that receives radio waves, and a receiving section that processes the output of the receiving antenna and controls the notification means. are placed at appropriate intervals, and
Transmit so that the receiving antenna is located at the location where fading occurs in the radio waves radiated from the transmitting antenna into the warning area.
The receiving section is configured to adjust each arrangement position of the receiving antenna and operate the notification means when the reception output of radio waves exceeds a preset level, and the transmitting section,
Since the presence or absence of an intruder is determined based on changes in the propagation state of radio waves between receiving sections, there is no need for a large number of intrusion sensors as in conventional systems, making installation easier and providing a crime prevention device that is inexpensive. The effect is that it can be done.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of the same operation, Fig. 3 is a block circuit diagram showing a specific example of the above, and Fig. 4 is a specific circuit diagram of the main parts of the same. be. 1 is a transmitter, 2 is a transmitting antenna, 3 is a receiving antenna, 4
5 is a receiving section, and 5 is a notification means. Figure 1 Figure 2 (b) na! ! Bowl diagram 4

Claims (2)

[Claims] (1) A transmitter that outputs a transmission signal in the very high frequency band or extremely high frequency band, one or more transmitting antennas that are excited by the transmitted signal, a receiving antenna that receives radio waves radiated from the transmitting antenna, and a receiving antenna. It consists of a receiving section that processes the antenna output signal and controls the notification means.The transmitting antenna and the receiving antenna are arranged at appropriate intervals at important points within the warning area such as indoors and inside the house, and the transmitting antenna and the receiving section are arranged at appropriate intervals. The positions of the transmitting and receiving antennas are adjusted so that the receiving antenna is located at the location where fading of the radio waves radiated within the warning area occurs, and when the receiving output of the radio waves exceeds a preset level. A crime prevention device characterized in that a receiving section is formed to operate a notification means. (2) The security device according to claim 1, wherein the receiving section is provided with reception level display means for displaying the reception output level.