JPS6243431Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is useful for detecting abnormal situations such as power outage, abnormally high or low temperatures in a house or greenhouse, non-ignition of a heater, or running out of fuel in a heavy oil or kerosene tank, and immediately reporting the situation. The present invention relates to a wireless alarm device suitable for application to.

As such a wireless warning device, for example, one shown in FIG. 1 has been proposed. In FIG. 1, 1 is a transmitter placed at a site such as a house or greenhouse, and 2 is a transmitter placed at a house or a management room, for example.

For example, the transmitter 1 uses a low frequency signal generated from a tuning fork oscillator to generate a crystal oscillator with an oscillation frequency of 13.56MHz.
Transmission frequency that is tripled after frequency modulation
It is configured to transmit 40.68MHz from the transmitting antenna 3. When an alarm contact signal that causes a short circuit between the terminals is input to the alarm input terminal 4 of the transmitter 1, the power of the transmitter 1 is automatically turned on and radio waves are emitted. After about 5 seconds, the alarm lamp 5 lights up, and transmission radio waves are emitted from the transmission antenna 3 at 2 second intervals. In order to avoid unnecessary battery consumption and unnecessary emission of radio waves, this transmitter 1 emits signals at 2-second intervals for approximately 30 seconds and then automatically stops. Note that 6 is a test button.

Radio waves emitted from the transmitter 1 in this manner are received by the transmitter 2 via the receiving antenna 7, and the speaker 8 emits sound. In order to avoid malfunctions due to noise or interference, the speaker 8 is configured to emit sound approximately 10 seconds after receiving the contact signal.
Once the speaker 8 emits sound, even if the radio waves from the transmitter 1 are stopped, the speaker 8 continues to emit sound unless the reset button 9 is pressed. By pressing the reset button 9, the speaker 8 stops emitting sound and returns to a normal reception state.

FIG. 2 shows an example of the circuit configuration of the receiver 2 shown in FIG. In FIG. 2, 10 is a high frequency amplifier, 11 is a mixing circuit, and 12 is a local oscillator. The frequency is converted to 10.7MHz by mixing with the first local oscillation frequency 29.98MHz, and then the second local oscillation frequency
By mixing with 10.245MHz, it is converted to a 455KHz intermediate frequency signal. From this 40.68MHz high frequency signal
Conversion to 455KHz is actually carried out using the so-called double superheterodyne method, which is performed by providing a first mixing circuit and a local oscillator, and a second mixing circuit and a local oscillator, but for the sake of explanation, they will be described together here. ing. This 455KHz intermediate frequency signal is amplified by an intermediate frequency amplification circuit 13, and then a frequency discriminator 1
4, the signal is demodulated into a low frequency signal and supplied to a tuner 15 using a tuning fork having the same frequency as that of the transmitter. Since the low frequency signal from the frequency discriminator 14 includes the entire range of audible frequencies including noise, a specific low frequency signal is extracted from the low frequency signal by the tuner 15.
The extracted specific low frequency signal is converted into a DC signal in the next stage rectifier amplifier circuit 16, amplified and supplied to a gate circuit 17 including an oscillation circuit, where it is further subjected to logic processing to produce a predetermined oscillation sound. is obtained. This oscillation sound is then amplified by the amplifier circuit 18 and generated as an alarm sound from the speaker 8.

By the way, in the wireless alarm device having the circuit configuration as described above, the gate circuit 17 accumulates input signals,
When the accumulated amount exceeds a certain level, it is configured to oscillate at an audio frequency, that is, to generate an alarm sound in accordance with the level of the abnormal situation detection signal. Therefore, even if an error signal exceeding the above-mentioned certain level is input, this will be generated as an alarm sound. As a person who remotely monitors abnormal situations in greenhouses, greenhouses, etc. using such alarm sounds, it is important to monitor each house, greenhouse, etc. every time the alarm sounds, regardless of whether it is an original abnormal situation detection signal or an error signal. Management had to go to a certain site to check, making management cumbersome and extremely inefficient.

The present invention was developed in view of this point, and is an excellent labor-saving wireless device that can switch and sort the alarm sound when it is generated, and instantly determine whether the original abnormal situation detection signal is an error signal. It provides an alarm device.

An embodiment of the present invention will be described in detail below with reference to FIG. In FIG. 3, parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

In this embodiment, changeover switches 19 and 20 are provided, and the changeover contact 19a of the changeover switch 19 is connected to the output side of the frequency discriminator 14, and the fixed contact 1
9b is connected to the input side of the harmonic waver 15, and the fixed contact 19c is connected to the fixed contact 20 of the changeover switch 20.
Connect to c. Further, the changeover contact 20a of the changeover switch 20 is connected to the input side of the amplifier circuit 18, and the fixed contact 20b is connected to the output side of the gate circuit 17.

In such a configuration, when the abnormality detection signal emitted at 2-second intervals can be normally received, the switching contact 19a of the switch 19 and the switching contact 20a of the switch 20 are connected to the fixed contacts 19b and 2, respectively.
0b and is used in a so-called normal operation mode in which an alarm sound is generated from the speaker 8 via the harmonic generator 15 or the like.

On the other hand, when the generated alarm sound is disturbed by noise or interference and it is difficult to determine whether it is a true alarm sound or an error signal, switching contacts 19a and 2
0a to the fixed contacts 19c and 20c, respectively, and the output of the frequency discriminator 14 is directly amplified by the amplifier 18 and taken out as a corresponding audio frequency signal by the speaker 8, and the difference in the audio frequency signals is used to detect the original abnormal situation. It is determined whether it is an error signal or an error signal. This extracted audio frequency signal differs between the abnormal situation detection signal and the error signal, and even among the error signals, it should differ depending on the radiation source.If you memorize these differences as audio frequency signals, you can easily detect abnormal situations. The signal can be verified and the source of the erroneous signal can also be determined.

As described above, according to the present invention, it is possible to immediately distinguish between an abnormal situation detection signal and an error signal with an extremely simple circuit configuration, and only when an audio frequency signal corresponding to the abnormal situation detection signal is obtained can the on-site Since all you have to do is go to the office, the troublesome management of conventional equipment is eliminated, resulting in labor savings.

In the above-described embodiment, the output of the frequency discriminator 14 is taken out as an audible sound and discriminated.
For example, the output of the frequency discriminator 14 may be passed through a filter and discriminated by a display such as a lamp.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional radio warning device, FIG. 2 is a block diagram specifically showing the receiver of FIG. 1, and FIG. 3 is a block diagram showing an embodiment of the present invention. 8 is a speaker, 10 is a high frequency amplification circuit, 11 is a mixing circuit, 12 is a local oscillator, 13 is an intermediate frequency amplification circuit, 14 is a frequency discriminator, 15 is a tuner, 16 is a rectification/amplification circuit, 17 is a gate circuit ,
18 is an amplifier circuit, and 19 and 20 are changeover switches.

Claims (1)

[Scope of utility model registration request] One set includes a transmitter that detects an abnormal situation and emits a transmission signal modulated by an audio frequency signal generated, and a receiver that receives the transmission signal emitted from the transmitter, discriminates the frequency, and generates an alarm signal. In a wireless alarm device that corresponds to a frequency-discriminated signal, a switch means is provided to switch and select whether the output of the frequency discriminator is supplied to the amplifier circuit via a tuned filter or directly to the amplifier circuit, and is adapted to respond to frequency-discriminated signals. A wireless warning device characterized in that an audio frequency signal is used to determine whether a signal is related to an abnormal situation or an error signal.