JPS6312411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a single radio device that can effectively prevent interference caused by simultaneous voice transmission in a single channel radio device that employs a selective calling method and has a tone squelch circuit. be.

In radio equipment (single radio equipment) that uses a single frequency to alternately transmit and receive data to and from the other station by means such as press talk, etc.
A tone squelch circuit is used to distinguish between the group to which the station belongs and other groups.
In the tone squelch, the transmitting side sends out an audio out-of-band signal (tone) determined for each group, and the receiving side detects this and releases the lock on the audio output circuit only in the case of the own group. This allows communication to take place between stations belonging to the group to which the identification tones have been assigned.

In a single radio equipped with such a tone squelch circuit, various methods are used to notify the operator of the call status of other stations, as described below.

(1) A busy lamp display method that provides a busy lamp to display the call status.

(2) A volume reduction monitoring method that monitors calls within your own group and calls from other groups based on volume levels.

(3) Switch monitor method in which tone squelch is canceled and monitored using a switch.

FIG. 1 is a block diagram showing the configuration of a conventional tone squelch system. A radio signal input from an antenna 1 is received by a receiver 2 and demodulated into audio. The tone of the demodulated voice is detected in a tone squelch circuit 3, whereby a control signal is applied to a busy lamp 4 or a control circuit 5. For example, in the case of a busy lamp display method, the busy lamp 4 indicates that the call is busy by blinking. The control circuit 5 consists of an attenuator or a switch, and in the case of the volume reduction monitor method, the amount of attenuation of the attenuator changes depending on the control signal, and the volume output from the audio amplifier 6 via the speaker 7 changes. You can monitor the call status of other groups at low volume. In the case of the switch monitor method, audio output is cut off when other groups are talking by turning the switch on or off using a control signal, but tone squelch can be canceled by manually operating the switch. can be monitored.

However, all of these conventional methods have the disadvantage that a message can be transmitted while another group is talking, causing interference. In the busy lamp display method (1), the operator must stare at the lamp before transmitting a call, and the operator must stare at the lamp before transmitting a call. I had to wait a while. Furthermore, in the volume reduction monitoring method (2) and the switch monitoring method (3), it is not possible to distinguish between no modulation and idle time. In addition, with the volume reduction monitoring method (2), it is possible to misjudge the volume depending on the modulation degree of the other station and the volume level depending on the setting of the own station's volume adjuster. The switch monitor method had the drawback of adding a switch operation to check if the call was busy, which increased the number of operational operations.

The present invention aims to eliminate such drawbacks of the prior art, and its purpose is to prevent the transmitter from operating even if another group is busy, and to prevent the transmitter from operating, and also to suppress the alarm sound. It is an object of the present invention to provide a system which prevents the occurrence of interference by generating a signal to notify an operator of a busy state, and which eliminates the drawbacks of the above-mentioned systems.

In order to achieve this objective, the single radio of the present invention uses a single call path using a selective calling method equipped with a tone squelch circuit that uses tones to distinguish calls in the own group from calls in other groups. In a radio device, when there is an output from the noise squelch circuit indicating that reception is in progress, but there is no output from the tone squelch circuit indicating reception of the own group's tone, an output is generated to disable the operation of the transmitter and activate an alarm generator. Equipped with a means to put it into a standby state,
This system is characterized by disabling the transmitter and generating a busy alarm when the own station initiates a transmission operation during a call with another group.

Examples will be described below.

FIG. 2 is a block diagram showing the configuration of an embodiment of a single radio device of the present invention. In the figure, 11 is a pre-talk switch, 12 is a gate, 13 is an antenna, 14 is a transmitter, 15 is a transmitter, 16 is a receiver, 17 is a speaker, 18 is a noise squelch circuit, 19 is a tone squelch circuit, 20, 21 is a gate, 22 is an alarm generator, and 23 is a control circuit.

In FIG. 2, when the pre-talk switch 11 is off, it is in the receiving state, and the transmitter 14 is turned off by the output of the gate 12. On the other hand, the receiver 16 is in an on state and is receiving an input signal from the antenna 13. The noise squelch circuit 18 generates an output "1" when a carrier wave is input, and otherwise generates an output "0". Furthermore, the tone squelch circuit 19 outputs “1” when receiving a tone from a station in its own group.
otherwise, an output "0" is produced.
The gate 20 operates based on the product of the output of the noise squelch circuit 18 and the output of the tone squelch circuit 19 to generate an output.

Noise squelch circuit 1 while other groups are talking
Since the output of the tone squelch circuit 19 is "1" and the output of the tone squelch circuit 19 is "0", the output of the gate 20 is "1", so that the gate 12 is in an inhibited state and the gate 21 is in a standby state. When the pre-talk switch 11 is turned on in this state, an output is generated from the gate 21 and the alarm generator 22 is operated. As a result, an alarm signal is applied from the alarm generator 22 to the speaker 17 to generate an audible busy alarm. On the other hand, since the gate 12 is in a disabled state, the transmitter 14 does not operate.

Next, when there is no carrier wave input, the output of the noise squelch circuit 18 and the output of the tone squelch circuit 19 are both "0", so the output of the gate 20 is "0", and the gate 21 is in the inhibited state. At the same time, the ban on Gate 12 will be lifted,
When the pre-talk switch 11 is turned on, the transmitter 14 becomes operational and can transmit audio signals via the transmitter 15.

The control circuit 23 connects the audio output of the receiver 16 to the speaker 17 using the output "1" of the tone squelch circuit 19. Therefore, the operator can listen to only the received signal of his own group through the speaker 17.

As is clear from the above explanation, in the single radio device of the present invention, unlike the conventional system in which the operator initiates a call transmission operation after confirming that other groups are not busy, the operator can confirm that a call is busy. The transmitting operation can be started immediately without the need for . If the line is empty, you can immediately proceed to the call, and if the line is busy with another group, you will be notified by an alarm that the line is busy, and in this case, transmission will not be performed. Because there is no
There will be no interference with other groups.

As described above, according to the single radio device of the present invention, the operational operation is simple and communication efficiency can be improved, and interference caused by sending a busy confirmation by mistake as in the conventional method can be avoided. Since this does not occur, it is possible to use radio waves effectively and to ensure communication order, which is extremely effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a conventional tone squelch system, and FIG. 2 is a block diagram showing the configuration of an embodiment of a single radio device of the present invention. DESCRIPTION OF SYMBOLS 1... Antenna, 2... Receiver, 3... Tone squelch circuit, 4... Busy lamp, 5... Control circuit, 6... Audio amplifier, 7... Speaker, 11...
...Press talk switch, 12...Gate, 13
... antenna, 14 ... transmitter, 15 ... transmitter, 16 ... receiver, 17 ... speaker, 18 ...
...Noise squelch circuit, 19...Tone squelch circuit, 20, 21...Gate, 22...Alarm generator, 23...Control circuit.

Claims (1)

[Claims] 1. In a single channel radio device that uses a selective calling method and is equipped with a tone squelch circuit that uses tones to distinguish calls from one's own group from calls from other groups, there is an output from the noise squelch circuit that indicates that reception is in progress. The tone squelch circuit generates an output when there is no output from the tone squelch circuit indicating reception of the own group's tone, inhibits the operation of the transmitter, and puts the alarm generator into a standby state, so as to prevent the own station from talking while another group is talking. A single radio device characterized in that when a transmitter starts a transmitting operation, a transmitter is disabled and a busy alarm is generated.