JP2617671B2 - Portable early warning device and method of using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an alarm device having an electromagnetic wave transmitter having an oscillator circuit and an antenna.

[0002]

BACKGROUND OF THE INVENTION Various alarm devices are known which use electromagnetic waves or ultrasonic waves to illuminate a given location and to measure the reflection received from the illumination. Whether they are ultrasound or infrared devices, all have the common feature that they only operate within the limitations of a room wall or entirely outdoors. Since the form of illumination commonly used in such known alarms does not traverse the walls of conventional buildings, if it is desired to obtain complete protection of the room, place the irradiation source outside the room. By the same principle that multiple video cameras need to be installed, room perimeter monitoring can only be performed by multiple illumination sources covering every angle and point of the environment.

[0003]

Obviously, the limitation of conventional alarm systems is the high cost resulting from the installation of multiple devices to obtain incomplete or complete monitoring.

[0004] Furthermore, known alarm systems emit an alarm signal as soon as the interior reflection pattern or the monitored space changes, and thus one of this pattern, such as the protection of a room where a meeting is held and in which people are moving. Useful in situations where certain changes are tolerated without an alarm, but the approach of a person outside the room wall must be displayed to alert conference participants that someone is listening. There is no.

The object of the present invention is to eliminate the above drawbacks, to allow movement within a certain area of the surveillance space, and to switch the alarm signal to occur only if movement occurs within a certain area. An early warning device and a method of using the same.

Another object of the present invention is to provide a portable early warning device which can be used for simultaneously observing the inside and the surroundings of a room without installing a large number of irradiation sources, and a method of using the same.

[0007]

In order to achieve the object of the present invention, an oscillator circuit has a first LC element, an antenna is directly connected to the first LC element, and an antenna to which the first LC element is connected. And the oscillator circuit are slightly mismatched with respect to the resonance frequency, the reflected wave of the radio wave first emitted from the antenna is received by the antenna, and if the distance between the antenna and the reflected object is If it is a multiple of half the wavelength, i.e. the reflected wave is in tune with the emitted electromagnetic wave, the oscillator current increases and the device further includes a switch circuit responsive to exceeding either oscillator current threshold. It is characterized by having.

According to another embodiment, an oscillator circuit includes a non-linear resistive energy sink capable of changing from a low resistance state to a high resistance state in response to the amount of current flow therethrough. Is tied to. The energy sink reacts to current changes in the oscillator circuit caused by the in-phase reflected signal received in the antenna, so that when such in-phase reflected signal is received in the antenna, the resistance of the energy sink is low. Is. In its low resistance state, the energy sink gives a high supply voltage due to the oscillator circuit, and in its high resistance state,
Because of the low supply voltage provided by the oscillator circuit, the reception of the in-phase reflected signal in the antenna increases the supply voltage and the signal output voltage of the oscillator circuit provided to the switch circuit for issuing an alarm.

In yet another embodiment, the oscillator is capable of producing high frequency frequency emission waves, and the LC element is placed in the collector branch circuit of the oscillator transistor which is part of the conventional modified oscillator emission circuit. ing.
In the same embodiment, the oscillator circuit has a second LC element disposed between the emitter of the oscillator transistor and ground, and a third LC element is connected to the emitter in a floating manner.

In one of the possible embodiments of the present invention, the high frequency properties of the radiation cause high frequencies even if the location to be monitored includes walls or other obstacles that obstruct the direct propagation of the radiation conventionally used. Crosses the wall without significant damping, so
Reflections obtained from obstacles outside the wall can be received by the antenna.

The energy sink appears to be in the emitter branch circuit of the oscillator transistor coupled to the second LC element. Conveniently, this energy sink is an incandescent light bulb.

According to an embodiment of the present invention, the switch circuit is directly connected to the coil of the LC element of the collector branch circuit of the oscillator transistor via the coupling capacitor, so that the switch circuit has a large number of switch transistors. , The base of a first switch transistor therein is connected to a coupling capacitor via a first diode, and the emitter therein is connected to the same coupling capacitor via a second diode. The diode points in the opposite direction.

The switch circuit has a second switch transistor, whose base is connected to the emitter of the first switch transistor, whose emitter is connected to the base of the third switch transistor, and whose emitter is connected to the alarm signal generator. And the collectors of all three switch transistors are connected to ground.

According to an embodiment of the invention, the alarm signal generator comprises a lamp and a sound generator, and the switch circuit comprises a lamp through an exchange switch for preselecting which type of alarm signal is desired. Or it can be connected to a sound generator.

The base of the oscillator transistor is connected to a positive voltage, generally in parallel with the first base capacitor and the base resistor, as well as to ground through a second base capacitor.

According to still another embodiment of the present invention,
The alarm device has a first and a first symmetrically arranged oscillator circuits.
It has two oscillator circuits (20a, 20b) and one oscillator circuit (2
The non-linear resistance energy sink (I) is connected between the power source side end of 0a) and the power source, and the intermediate point of the first and second oscillator circuits is connected.
(P) is connected to an amplifier for amplifying the audio frequency signal. When the frequency of one of the first and second oscillator circuits changes due to the in-phase reflected wave received by the antenna, a point ( An audio frequency signal is generated at P), this audio frequency signal is input to the amplifier 22 and amplified, and is acoustically reproduced as an alarm signal.

The invention also relates to a method of protecting a place against intruders, which method of use of a portable early warning device according to the invention comprises:
Install in the center of the monitored area. The oscillator circuit and the antenna are slightly mismatched with respect to the resonance frequency under the special reflection conditions of the monitored location, and the area around the antenna having a radius corresponding to a multiple of half the wavelength of the electromagnetic waves emitted by the antenna; Each time an intruder passes through a point on a number of concentric surfaces, the antenna of the device is tuned to obtain an alarm signal.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows a conference room 1 surrounded by a wall 2 and closed by a door 3. A portable early warning device 5 of the present invention is used for a conference near the center of the room. It is installed on the table 4 so as to illuminate the conference room and the surroundings with a wavelength in the high frequency range. The particular wavelength can be selected so as to obtain the desired arrangement of circles 6, 7, 8 (or more) corresponding to an integral multiple of the half-wavelength λ / 2 of the radio frequency used.

The antenna of the portable early warning device 5 transmitting high frequencies receives reflections from all objects within its transmission range and is tuned with respect to the resonance frequency such that some combination mismatch with the oscillator occurs. Thus, the oscillator is ready to resonate for slight changes in antenna current as in the in-phase reflected signal in the antenna. The oscillator remains in some combinatorial incompatibility unless in-phase reflections originating from points located on circles 6, 7 or 8 are received.

Since the orbit of the object (reflector) located in one of the circles corresponds to an integral multiple of a half wavelength, the reflected wave is returned to the antenna in phase with the emission signal.
The reflected wave thus received is superimposed on the oscillator current in the emission oscillator (described later) to reinforce the oscillator current. On the other hand, any reflected wave that is not in phase with the emitted wave does not increase the oscillator current.

Arrows 9, 10 and 11 are half-wave circles 6, 7
9 is a typical example of a motion indicating a motion of a human being or an object in the same space section related to 8 and 8 and not issuing an alarm. Arrow
12, 13 and 14 show a movement of a human across a half-wave circle, during which the reflected wave is in phase with the emitted wave and is emitted to the antenna, so the alarm is issued during this time.

FIG. 2 shows an electronic circuit diagram of a possible embodiment of the portable early warning device 5 of the present invention.

The reference sign S designates a voltage divider providing an output voltage which is reduced compared to the main supply voltage of the circuit shown in FIG. The main supply voltage is, for example, 12 V, the divided voltage of 8 V is an output for an electronic circuit, and the main supply voltage of 12 V is used for an alarm unit to be described later.

Oscillator circuit 20 includes an oscillator transistor T1, the base of which is maintained at the proper voltage level by a resistor R and capacitors C1 and C2 connected to a positive potential. C1 is connected to a positive potential,
C2 is then connected to ground via the resistance of the incandescent lamp I acting as an indirect resistance energy sink. The collector of the transistor T1 is a coil L1 and a capacitor C3.
Is connected to a first LC element, the time constant of which corresponds to the desired frequency.

The emitter of the transistor T1 is a coil L2
And a second LC element formed of a capacitor C4, and the time constant of this second LC element is the same as that of the first LC element. The second LC element is further connected to an incandescent lamp.

The emitter of the transistor T1 is the coil L.
3 and further connected to a floating third LC element formed by a capacitor C5 for balancing with the antenna connected to the first LC element. All capacitors of the three LC elements are used as adjustable capacitors.

The antenna A is connected to the midpoint of the coil L1 of the first LC element, and its second midpoint has a coupling capacitor C6 which passes the high frequency current from the coil L1 to the switch circuit 30 with almost no ohmic resistance. Connected to.

The switch circuit 30 includes diodes D1 and D2.
And three switch transistors T2, T3 and T4
And diode D1 is connected between coupling capacitor C6 and transistor T2 in a direction that allows the passage of oscillator current to the base of negative half-wave transistor T2. The diode D2 is connected between the coupling capacitor C6 and the emitter of the transistor T2 in a direction that allows the positive half-wave of the oscillator current to pass to the emitter. It is clear that if the oscillator current is strong enough to provide the required emitter-base potential, transistor T2 will be shut off. When the transistor T2 conducts, the transistors T3 and T4, which are succeeding transistors of the cascade-connected transistor T2, also conduct, and the unit AL1
Or one of the two types of alarms in which AL2 is generated, an optical alarm or an audible alarm. AL1
Is an optical alarm device, for example in the form of a lamp, AL2
Is an acoustic alarm such as a speaker. The exchange switch 21 can select a desired alarm type (type) in advance.

The different types of alarms generated by units AL1 or AL2, respectively, provide the same impedance condition to provide the same impedance condition regardless of the preference of the type of alarm.
8 are connected to each other.

The antenna A is connected to the intermediate contact of the coil L1 and receives from the coil its high frequency current radiated by the antenna A to illuminate the location monitored by the portable early warning device 5. Since this antenna is tuned to provide some resonance mismatch with the oscillator, the oscillator circuit 20 will not operate at its resonance frequency and the amplitude of the oscillator current will therefore not reach saturation. If the in-phase reflection is captured by antenna A, the antenna current generated by this received wave will be superimposed on the oscillator current for the emitted wave, increasing the high frequency current flowing through coupling capacitor C6 and causing switch circuit 30 to Activate the two alarm units AL1 or AL2.

In a balanced state, where the in-phase reflected signal is not received by antenna A, the oscillator operates slightly out of resonance and therefore the high frequency output current is small. In this case, the direct current passing through the oscillator and also through the lamp (I), which is the energy sink I connected thereto, is at a high voltage, so that the lamp heats up and produces a high resistance state. In this case, the majority of the circuit supply voltage drops across the lamp and the residual oscillator supply voltage is relatively low, so the RF output voltage is also low. The RF signal provided to switch circuit 30 is therefore too small to shut off transistor T2.

If the in-phase reflected wave is received in the antenna A, the first LC oscillating elements L1 and C3 approach or reach resonance, and the amplitude of the high frequency current in the oscillator circuit increases, and the oscillating circuit. The DC component of 20 is reduced, resulting in a ramp
(I) is turned off, and the remaining supply voltage of the oscillator circuit 20 increases, causing a sharp increase in the high-frequency output voltage of the oscillator circuit 20. This sudden increase is transmitted to the switch circuit 30 that issues an alarm.

Thus, the reception of the in-phase reflected wave at the antenna A is caused by the reflection of the high frequency electromagnetic wave emitted in one of the half-wave cycles, and the alarm signal is issued.

FIG. 3 shows an electronic circuit of another embodiment of the present invention. In this embodiment, the oscillator circuit comprises two symmetric high frequency oscillator circuits 20 tuned to the same frequency.
a and 20b, only one 20b of which is connected to the antenna A. When the in-phase reflected wave is not received by the antenna A, the high frequency wave whose amplitude is attenuated is not received. However, when the in-phase reflected signal is received and input from the antenna A to the oscillator circuit 20b, the oscillator circuit 20b
Changes somewhat to output an audio frequency oscillation at point P corresponding to the different frequencies generated in the two oscillator circuits.

The two oscillator circuits are connected in series in a manner similar to that described with reference to FIG. 2 together with a ramp (I) which serves to increase the rate of change of the frequency of the oscillator 20b to the received antenna signal. It

The audio frequency current from point P is coupled to amplifier 22 through capacitor C6, the output of which is provided to speaker LS.

It is contemplated that various modifications may be made to the invention described above with reference to the embodiments, which will be apparent to those skilled in the art and do not depart from the spirit and scope of the invention.

[0038]

As described above, the present invention allows a movement in a certain area of a monitored space, and is switched so that an alarm signal is generated only when a movement occurs in a specific area. There is an effect that the inside and the surroundings of the room can be observed simultaneously without installing many irradiation sources.

[Brief description of the drawings]

FIG. 1 is a schematic view of a region protected by an alarm device according to an embodiment of the present invention.

FIG. 2 is an electronic circuit diagram of the alarm device of the embodiment.

FIG. 3 is an electronic circuit diagram of another embodiment of the above.

[Explanation of symbols]

 A Antenna L1 to L3 Coil C1 to C6, C8 Capacitor T1 to T4 Transistor I Energy sink 20 Oscillator D1, D2 Diode 30 Switch circuit AL1 Lamp AL2 Sound generator R Base resistor

Claims (15)

(57) [Claims] 1. An electromagnetic wave transmitter having an oscillator circuit and an antenna, wherein the oscillator circuit (20) comprises a first LC element.
(L1, C3), and the antenna (A) has a first LC element (L
1, C3) are directly connected to the first LC element (L1,
The antenna (A) to which C3 is connected and the oscillator circuit (20) are slightly mismatched with respect to their resonance frequencies, and the reflected wave of the electromagnetic wave first emitted from the antenna (A) is When the distance between the antenna (A) and the reflector is a multiple of the half-wave (λ / 2) of the electromagnetic wave, that is, when the reflected wave is in phase with the emitted wave, the amplitude of the oscillator current is received. And a switch circuit (30) which is activated in response to exceeding the threshold value of the amplitude of the oscillating current in either direction. 2. The oscillator circuit (20) includes a nonlinear resistance energy sink that changes from a high resistance state to a low resistance state in response to an amount of current passing between the oscillator circuit (20) and a driving power source of the oscillator circuit (20). 2. The portable early warning device according to claim 1, wherein I) is connected in series. 3. The resistance of the energy sink (I) decreases when the antenna (A) receives an in-phase reflected wave due to an increase in current in the oscillator circuit (20) generated by the received in-phase reflected wave. The portable early warning device according to claim 2. 4. An energy sink in a low resistance state
(I) applies a high power supply voltage to the oscillator circuit (20), and applies a low power supply voltage to the oscillator circuit (20) in the high resistance state;
3. The portable early warning device according to claim 2, wherein the in-phase reflected wave received by the antenna (A) increases the power supply voltage and the output of the oscillator circuit (20) input to the switch circuit for issuing a warning. 5. An oscillator circuit (20) is a high-frequency oscillator capable of generating a high-frequency emission wave, and another connection point between the power supply side of the first LC element (L1, C3) and the collector of the oscillator transistor (T1) is connected. The portable early warning device according to any one of claims 1 to 4, wherein the portable early warning device is provided. 6. The oscillator circuit (20) is an oscillator transistor.
A second LC connected between the emitter of (T1) and ground
6. A portable early warning device according to claim 5, characterized in that it has elements (L2, C4). 7. A portable early warning device according to claim 6, characterized in that the oscillator circuit (20) has a third LC element (L3, C5) connected to the floating emitter. 8. The energy sink (I) is a second LC element.
The portable early warning device according to claim 5 or 7, wherein the portable early warning device is connected to an emitter of an oscillator transistor (T1) connected to (L2, C4). 9. The portable early warning device according to claim 8, wherein the energy sink (I) is an incandescent light bulb. 10. The switch circuit (30) includes a coupling capacitor.
(C6) is connected to the coil (L1) of the first LC element of the collector branch circuit of the oscillator transistor (T1), and the switch circuit (30) is connected to a large number of switch transistors (T2, T1).
3, T4), in which the first switch transistor
The base of (T2) is connected to the coupling capacitor (C6) via the first diode (D1), and the emitter therein is the same coupling capacitor (C6) via the second diode (D2).
A portable early warning device according to any of the preceding claims, wherein the device is connected to (6), whereby the diodes are oriented in opposite directions. 11. The oscillator circuit has first and second oscillator circuits (20a, 20b) symmetrically arranged, and is non-linear between the power source side end of one oscillator circuit (20a) and the power source. The intermediate resistance (P) of the first and second oscillator circuits is connected to an amplifier for amplifying the audio frequency signal, and the first and second oscillators are connected by an in-phase reflected wave received by the antenna. When the frequency of one of the oscillator circuits in the circuit changes, an audio frequency signal is generated at a point (P) between the oscillator circuits, and the audio frequency signal is input to the amplifier (22) and amplified, and an audio signal is generated as an alarm signal. The portable early warning device according to claim 1, wherein the portable early warning device is reproduced. 12. The switch circuit (30) has a second switch transistor (T3), the base of which is connected to the emitter of the first switch transistor (T2) and the emitter of the second switch transistor (T4). )
, The emitter of the third switch transistor is connected to the alarm signal generator (AL1, AL2),
All these three switch transistors (T1, T
The portable early warning device according to claim 10, wherein the collector of (2, T3) is connected to the ground. 13. The alarm signal generator (AL1, AL2) has a lamp (AL1) and a sound generator (AL2), and the lamp (AL1) is passed through a switch circuit (30) or an exchange switch (21).
Alternatively, the portable early warning device according to claim 12, which is connected to the sound generator (AL2). 14. The oscillator transistor (T1) has a base connected to ground via a second base capacitor (C2) as well as to a positive voltage and parallel thereto via a first base capacitor (C1). And a base resistor (R) connected to the base resistor (R).
The portable early warning device according to any one of 12 to 13. 15. In an electromagnetic wave transmitter having an oscillator circuit and an antenna, the oscillator circuit (20) comprises a first LC element.
(L1, C3), and the antenna (A) has a first LC element (L
, C3) and the first LC element (L1,
The antenna (A) to which C3 is connected and the oscillator circuit (20) are slightly mismatched with respect to their resonance frequencies, and the reflected wave of the electromagnetic wave first emitted from the antenna (A) is When the distance between the antenna (A) and the reflector is a multiple of the half-wave (λ / 2) of the electromagnetic wave, that is, when the reflected wave is in phase with the emitted wave, the amplitude of the oscillator current is received. The use of a portable early warning device comprising a switch circuit (30) activated in response to exceeding the threshold of the amplitude of the oscillating current in either direction. The step of installing in the approximate center of the place to be monitored and the intruder's radius is the antenna (A)
A number of concentric circles (6,7,8) around the antenna corresponding to multiples of the half wavelength (λ / 2) of the electromagnetic wave emitted by
At their resonant frequency, to obtain an alarm signal each time one of the points passes, at their resonant frequency, the oscillator circuit (20) and the first LC element (L1,
C3) adjusting the tuning frequency of the antenna so that it is slightly mismatched with the connected antenna.