JPS62112426A - Simultaneous talking type communication equipment - Google Patents

Abstract

PURPOSE:To coincide the receptionable region of a call signal at a standby state with a receptionable region at a talking state by suppressing the reception sensitivity of a reception system lower at the standby state of the titled equipment and setting the sensitivity nearly the same as a sensitivity level lowered by the invasion of a transmission signal at talking. CONSTITUTION:A hook switch 22 is operated at the standby state and sends a detection signal 22a. A transmission circuit 31 stops the operation at the standby state and an antenna 1 is used for receiving a signal only. In this state, a resistor 211 of a signal attenuation circuit 21 is inserted in the reception line and the signal attenuation of the circuit 21 is increased. When a handset hooks off after the call tone is recognized, the detection signal 22a of the hook switch 22 is lost and the transmission signal is sent from the circuit 31. A part of the transmission signal is leaked to the reception system 2 at a multicoupler circuit 4 thereby lowering the reception sensitivity of the reception system 2 relatively. When the detection signal 22a is lost, a switch contact 212 of the circuit 21 is closed to decrease the signal attenuation of the circuit 21.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a simultaneous call type communication device, and particularly to a communication device in which one antenna is shared by a receiving system and a transmitting system.

[Prior Art] Simultaneous call type communication devices do not require troublesome switch operations to select transmission and reception, and can enjoy remote calls as easily as normal telephone calls. In such a communication device,
In order to simplify the device, some devices have a configuration in which a single antenna for transmitting and receiving is shared by the receiving system and the transmitting system, but in this case, the following problems often occur.

[Problems to be Solved by the Invention] In other words, when a communication device is in a standby state, the transmitting system is not operating, so the receiving system has sufficient reception sensitivity and can be received from other devices over a relatively wide range. receive a call signal. However, when the communication device enters a call state in response to the above-mentioned call signal, the transmission signal from the transmission system is superimposed on the above-mentioned antenna, and some of this leaks to the reception system, so the reception sensitivity of the call signal is relatively low. descend. This causes a problem in that although the calling signal is received clearly enough, the voice of the other party cannot be heard when the call state is entered.

SUMMARY OF THE INVENTION In view of these problems, it is an object of the present invention to provide a simultaneous call type communication device that eliminates the above-mentioned problems by making the reception sensitivity of a calling signal equal to the reception sensitivity of a call signal.

[Means for Solving the Problems] The configuration of the present invention will be explained with reference to FIG. 1. An antenna 1 is connected to a receiving system 2 and a transmitting system 3. The SAMURAI state detection means 22 detects the waiting state of the communication device and issues a detection signal 22a. The receiving system 2 is provided with a signal attenuation means 21, and the signal attenuation means increases the amount of signal attenuation when the detection signal 22a is input, and decreases the amount of signal attenuation when the signal 22a is not generated by human input. .

[Function and Effect 1] According to the communication device having the above configuration, the receiving sensitivity of the receiving system 2 is suppressed to a low level by the signal attenuating means 21 when the device is in the waiting state, and the sensitivity level is almost the same as that which decreases due to the mixing of the transmission signal of waiting for a call. Set to be the same.

Thereby, the receivable area of the call signal received in the standby state and the receivable area of the call signal received in the call state are made to match, and it is possible to reliably communicate with the other party to whom the call is made.

[Embodiment] FIG. 1 is a block diagram showing the configuration of a communication device of the present invention. In the figure, 1 is an antenna, and the antenna 1 is connected to a receiving system 21) and a transmitting system 3 via an antenna common circuit 4.
or connected. The receiving system 2 includes a signal attenuation circuit 21, a knock switch 22 for detecting a samurai state, a receiving circuit 23.
The transmitting system 3 is composed of a transmitting circuit 31 and a microphone 32.

The hook switch 22 connects the speaker 26 and the microphone 32.
The transducer/receiver (equivalent) equipped with this operates in a state where it is locked, that is, in a samurai state, and the detection signal 22a8 is emitted 4
Ru. The signal attenuation circuit 21 increases the amount of signal attenuation when the signal 22a is input. The receiving circuit 23 demodulates the storage signal and the speech signal received by the antenna 1. The demodulated ringing signal 23a is input to the ringing tone generation circuit 25. The ringing tone generation circuit 25 is in a waiting state and receives the above signal 23.
When a is input, it is sent to the speaker 2 via the summing amplifier circuit 24.
Sends a ring tone to G. The demodulated speech signal 23b is directly input to the speaker 26 via the amplifier circuit 24.

Details of the attenuation circuit 21 and receiving circuit 23 are shown in FIG. The attenuation circuit 21 is composed of a resistor 211 provided on the receiving line and a switch contact 212 connected in parallel to the resistor 211. The switch contact 212 is opened when a detection signal 22a is input, and closed when the detection signal 22a is not input. When the device is in a standby state, the resistor 211 is inserted into the receiving line, thereby reducing the receiving sensitivity.

The receiving circuit 23 includes a front end 231 that converts a high frequency received signal into an intermediate frequency, an intermediate frequency amplifying circuit 232, and a demodulating circuit 233 including a muting circuit.

In the above communication device, in the standby state, the transmitting circuit 31 is inactive, and the antenna 1 is used only for signal reception. In this state, as described above, the resistor 211 of the signal attenuation circuit 21 is inserted into the reception line, and the attenuation circuit 21
The amount of signal attenuation is large, and only the calling signals received by the antenna 1 that have sufficient human presence from within a proper area are demodulated by the receiving circuit 23 and recognized.

When the user hears the ringing tone 52 and picks up the handset, the detection signal 22a from the hook switch 22 is canceled and the transmission circuit 31 emits a transmission signal.

The transmitted signal is sent to the antenna common circuit 4, and a part of it is sent to the receiving system 2.
This causes the receiving sensitivity of the receiving system 2 to decrease relatively. Here, in the present invention, the detection signal 22a
When the signal attenuation circuit 21 is cleared, the switch contact 212 of the signal attenuation circuit 21
is closed, and the amount of signal attenuation of the circuit 21 becomes smaller.

In this way, the call signal arriving from within the proper area where the calling signal was received is reliably received and demodulated by the receiving circuit 23 without being attenuated by the attenuating circuit 21.

FIG. 3 shows another example of the signal attenuation circuit 21.

In the figure, 213, 214, and 215 are PIN diodes, and these diodes 213 to 215 have a characteristic that the resistance valve continuously changes according to the voltage applied thereto during jlji bias. Therefore, switch contacts 216 and 217 are provided which are selectively actuated by the detection signal 22a, and different divided voltages ya,
By applying yb to the diode 215, the resistance of the receiving line changes and the amount of signal attenuation is changed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of the communication device of the present invention, FIG. 2 is a block diagram showing the main parts thereof, and FIG. 3 is a circuit diagram showing another example of the signal attenuation circuit. 1...Antenna 2...
Receiving system 21...Signal attenuation circuit 22...Hook switch (waiting state detection means)
23... Receiving circuit 26... Speaker 3... Transmitting system 31... Transmitting circuit 32... Microphone 4... Antenna common circuit Figure 1 Figure 2

Claims (1)

[Claims] In a communication device in which one antenna is shared by a receiving system and a transmitting system to perform simultaneous calls, a waiting state detection means for detecting a call waiting state of the communication device and emitting a detection signal, and a waiting state detection means provided in the receiving system, A simultaneous call type communication device comprising signal attenuation means that increases the amount of signal attenuation when the detection signal is input, and decreases when the detection signal is not input.