JPH0870254A - House-to-house receiver - Google Patents

Abstract

PURPOSE: To attain the transmission of a signal from a house-to-house respectively to a base station by using a local frequency from a 1st local oscillator section for a carrier, superimposing a digital selective call signal on the carrier and emitting the resulting signal from a reception antenna. CONSTITUTION: When an accident takes place and the transmission of a rescue signal is desired to be sent to a base station, a microcomputer 7 is controlled and a switch 11 is provided to select a house-to-house receiver is switched to the transmission mode, and when the switch 11 is depressed, the microcomputer 7 generates a digital selective call signal as a rescue signal. Then a digital modulator 12 modulates the signal digitally and a 1st local oscillator section 4 superimposes the modulated signal onto the local frequency and sent from an antenna 1 through a switch 13 controlled by the microcomputer 7. When a base station sends an emergency signal, the emergency signal sent with the digital selective call signal is detected by the microcomputer 7, the microcomputer 7 generates the digital selective call signal as a called signal, the digital modulator 12 modulates the signal digitally, the 1st local oscillator section 4 superimposes the signal onto the local frequency and the resulting signal is sent through the switch 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency transmission in a door-to-door receiver.

[0002]

2. Description of the Related Art A conventional example will be described with reference to FIG. The signal received from the antenna 1 passes through the front end 2, is mixed by the mixer 3 with the local frequency output from the first local oscillator 4, and is then demodulated by the demodulation circuit 5. Furthermore, the digital demodulator 6
Is converted into a digital signal and converted into a digital select signal, which is input to the microcomputer 7. The microcomputer 7 controls the squelch circuit 8 based on the digital selection signal, controls the input of the audio signal demodulated by the demodulation circuit 5 to the audio amplifier 9, and amplifies the audio signal by the audio amplifier 9. The produced audio signal is output by the speaker 10.

[0003]

However, since the signal is one-way from the base station to the door-to-door receiver, the door-to-door receiver cannot send a rescue signal to the base station at the time of a disaster such as a landslide. There was a problem to say. In addition, there is a problem that the base station cannot determine whether or not the door-to-door receiver is receiving in an emergency.

[0004]

In order to solve the above problems, the present invention uses the local frequency emitted from the first station starter 4 as a carrier, superimposes a digital select signal, and radiates it from a receiving antenna. Make it possible to do.

[0005]

As a result, it becomes possible to transmit a signal from the door-to-door receiver side to the base station.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of transmitting a rescue signal from a door-to-door receiver to a base station will be described with reference to FIG. The signal received from the antenna 1 passes through the front end 2, is mixed by the mixer 3 with the local frequency output from the first local oscillator 4, and is then demodulated by the demodulation circuit 5. Further, it is converted into a digital signal by the digital demodulator 6 to be a digital select signal, which is input to the microcomputer 7. The microcomputer 7 controls the squelch circuit 8 based on the digital selection signal, and the demodulation circuit 5
The input of the audio signal demodulated by the audio amplifier 9 is controlled, and the audio signal amplified by the audio amplifier 9 is output by the speaker 10.

When a disaster occurs and it is desired to send a rescue signal to the base station, a switch 11 for controlling the microcomputer to switch the door-to-door receiver to the transmission mode is provided, and when the switch 11 is pressed, the microcomputer 7 sends a digital select signal. It is produced as a rescue signal, digitally modulated by the digital modulator 12, superposed on the local frequency by the first station starter 4, and transmitted from the antenna 1 through the switch 13 controlled by the microcomputer 7. In the case of the above-mentioned door-to-door reception system, when a digital select call signal is sent from the door-to-door receiver to the base station unspecified, it is predetermined as a rescue signal of the door-to-door receiver.

Next, a method for confirming whether the signal sent from the base station is received by the door-to-door receiver side will be described below. The signal received from the antenna 1 passes through the front end 2, is mixed by the mixer 3 with the local frequency output from the first local oscillator 4, and is then demodulated by the demodulation circuit 5. Further, it is converted into a digital signal by the digital demodulator 6 to be a digital select signal, which is input to the microcomputer 7. The microcomputer 7 controls the squelch circuit 8 based on the digital selection signal, controls the input of the audio signal demodulated by the demodulation circuit 5 to the audio amplifier 9, and amplifies the audio signal by the audio amplifier 9. The produced audio signal is output by the speaker 10.

When the base station sends an emergency signal, the microcomputer 7 detects the emergency signal sent together with the digital select signal, and the microcomputer 7 produces the digital select signal as an incoming signal and digitally modulates it. It is digitally modulated by the device 12 and superposed on the local frequency by the first station starter 4,
It transmits from the antenna 1 through the switch 13 controlled by the microcomputer 7.

[0010]

According to the present invention, a rescue signal at the time of a disaster can be sent from a door-to-door receiver to a base station. Further, the base station side can confirm whether or not the door-to-door receiver has received the emergency signal sent by the base station.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example.

[Explanation of symbols]

 1 Antenna 2 Front End 3 Mixer 4 First Station Starter 5 Demodulator 6 Digital Demodulator 7 Microcomputer 8 Squelch Circuit 9 Audio Amplifier 10 Speaker 11 Switch 12 Digital Modulator 13 Switch

Claims (3)

[Claims] 1. A door-to-door receiver including an FM receiver for receiving a transmission signal from a base station and a digital selector signal detection unit including a digital demodulation circuit and a microcomputer. A door-to-door receiver characterized by having a transmitting means for transmitting information to a base station. 2. An FM receiver comprising an antenna, a front end, a mixer, a first local oscillator, a demodulation circuit, a squelch circuit, an audio amplifier, and a speaker, and a digital demodulation circuit and a microcomputer. In a door-to-door receiver composed of a digital celerometer signal detection unit, a transmission mode changeover switch for controlling a microcomputer to switch the door-to-door receiver to a transmission mode is provided, and by pressing the switch, the F
A door-to-door receiver, characterized in that a digital cel- lector signal generated by a microcomputer and a digital modulation circuit is superimposed on a carrier of a local oscillator of the M receiver and radiated from an antenna. 3. When receiving an emergency signal from a base station, a digital select signal produced by a microcomputer and a digital modulation circuit is superimposed on a carrier of a local oscillator of an FM receiver,
The door-to-door receiver according to claim 2, wherein the receiver radiates from an antenna.