JPS6150539B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmitting/receiving switching device, and more particularly to a transmitting/receiving switching device when an earplug type earphone is also used as a microphone.

For example, when using a radio telephone while driving a car or engaged in fire extinguishing work, there may be cases where you cannot use your hands to operate the radio telephone. It is convenient to insert earplug-type earphones into your ears and use them both as earphones and as a microphone. This also applies when the operator has to use his hands for other tasks when talking on a wired telephone. Alternatively, if the surrounding noise level is high, you can use the above-mentioned earplug-type earphones by inserting them in your ears, blocking out the surrounding noise and transmitting the audio signals generated by the earplug-type earphones to the ears of the interlocutor. It is convenient because the voice generated by the interlocutor can be propagated through the interlocutor's head structure and transmitted to the earplug type earphone.

When earplug-type earphones are used in the above-mentioned situations, in order to switch the above-mentioned telephone (wireless telephone or wired telephone) from connection in reception mode to connection in transmission mode, a conventionally known voice-operated transmitting/receiving switch is used. Signal generation circuits cannot be used.
In other words, in conventional circuits, when a telephone is connected in reception mode, an earplug-type earphone is used as a microphone to generate an electrical signal, which then generates a transmit/receive switching signal, but in this case, the transmission line and earplugs This is because, since the earphone is connected to the earphone, a problem arises in that the transmission/reception switching signal is also generated by the electrical signal input from the transmission line to the earphone.

The purpose of this invention is to eliminate the above-mentioned drawbacks in conventional voice-operated transmitting/receiving switching signal generation circuits.For this purpose, the present invention amplifies the output of a reversible electroacoustic transducer and inputs it to a transmission line. a first amplifier for amplifying the signal transmitted by the line and a second amplifier for inputting the amplified signal to the electroacoustic transducer; When in transmission mode, the above-mentioned first amplifier is connected to the device, and when in reception mode (and reception standby mode), the above-mentioned second amplifier is connected, and the transmission mode and reception mode (and reception standby mode) are connected. The direction of transmission of electrical signals in is reversed. In addition, the connection of the transmitting/receiving switch in the reception standby mode and the reception mode is exactly the same, but the state in which the electric signal is input from the transmission line to the electroacoustic transducer is called the reception mode, and the above-mentioned electric signal A state in which there is no one is called reception standby mode.

The invention further includes a circuit for prohibiting switching of the transmitting/receiving switch when in the receiving mode,
The operation of the transmitting/receiving switching device is made more reliable. Embodiments of the invention will be described below with reference to the drawings.

The figure is a block diagram showing one embodiment of this invention.
1 is a first amplifier, 2 is a second amplifier, 3 and 4 are respective amplifiers, 5 is a reversible electroacoustic transducer,
6 is a transmission line, 7 is a transmit/receive switch;
1, 72 are the movable contacts, 73, 74, 75, 7
6 indicates its fixed contact. The switch 7 is operated by a relay, but the relay coil is omitted from the drawing. 81 is a first waveform shaping circuit, 82 is a second waveform shaping circuit, 91 is a first monostable multivibrator, 92 is a second monostable multivibrator, 11 is a flip-flop, and 12 is a transmit/receive switching signal output terminal. It is.

In the transmit mode, contact 71 becomes contact 73, contact 7
2 is connected to the contact 74 (this state is referred to as the first contact position), and the output of the electroacoustic transducer 5 is amplified by the amplifier 1 and output to the transmission line 6. The passage of electrical signals to is blocked by amplifier 1.

In this state, the output of the electroacoustic transducer 5 is also input to the amplifier 4, and the output of the amplifier 4 is transmitted to the waveform shaping circuit 8.
2, but while the output of the electroacoustic transducer 5 is at a peak value comparable to normal voice transmission, the waveform shaping circuit 82 does not operate, and therefore the monostable multivibrator 92 does not operate.

In order to operate the multivibrator 92, it is necessary for the electroacoustic transducer 5 to generate a voltage with a much higher peak value than in the case of normal voice transmission. This can easily occur when the speaker who is inserting the electroacoustic transducer 5 as an earplug performs an operation such as clenching his or her teeth together. Further, the characteristics of the amplifier 4 can be designed so as to obtain a good gain for the pulse wave generated when the teeth are engaged.

When a waveform with a high peak value is input to the amplifier 4 in this way, an output signal can be obtained at the output point of the waveform shaping circuit 82, and the multivibrator 92
is triggered, its output is inverted (from the second logic, e.g., logic "0", to the first logic, e.g., logic "1"), and the state is maintained for a predetermined period of time (e.g., 0.5 seconds to 1 second). After being held, it returns to its original state (logic "0" state in the above example).

The flip-flop 11 is inverted using the pulse during the time when the output of the multivibrator 92 is in the inverted state, and the output switches the switch 7 from the first contact position to the second contact position via the relay.

At the second contact position, the contact 71 is connected to the contact 75 and the contact 72 is connected to the contact 76, thereby establishing a reception standby mode connection. Even in the reception standby mode connection, the output of the multivibrator 92 can be inverted by engaging the teeth or the like, and the flip-flop 11 can be inverted using the pulse while the multivibrator 92 is in the inverted state. When switch 7 is in the second contact position and flip-flop 11 is inverted, the output at its output terminal 12 causes switch 7 to return to the first contact position.

Therefore, when in the transmission mode, the multivibrator 92 can be operated to set the reception standby mode, and when in the reception standby mode, the multivibrator 92 can be operated in the same way to set the transmission mode.

When the switch 7 is in the second contact position, when an electrical signal is input to the amplifier 3 from the transmission line 6, the output of the multivibrator 91 is inverted by this signal. While this signal continues, the output of the multivibrator 91 is held in an inverted state, and when this signal disappears for 0.5 seconds to 1 second, the output of the multivibrator 91 returns to its original state. The above-mentioned reception mode may be considered to mean a state in which the output of the multivibrator 91 is inverted. Second monostable multivibrator 9
2 is controlled by the output of the first monostable multivibrator 91, and when the output of the multivibrator 91 is in an inverted state, the multivibrator 9
2 inversion operation is prohibited. Therefore, in the receiving mode, there is an electrical signal input along the path of transmission line 6 → amplifier 2 → amplifier 4, and in some cases there is an electrical signal input along the path of electroacoustic transducer 5 → amplifier 4. Multivibrator 92 does not operate.

In the above description, the transmission line 6 may be directly connected to the other party's reversible electroacoustic transducer, or in the case of a wireless telephone, may be connected to a wireless telephone transmitting/receiving device. In the case of a radiotelephone, the internal connections of the radiotelephone transmitter/receiver also need to be switched between transmitting and receiving, and in this case this can be done by a switch that works with the switch 7.

As described above, according to the present invention, it is possible to obtain a transmitting/receiving switching device suitable for the case where a single reversible electroacoustic transducer is used both as an earphone and as a microphone.

[Brief explanation of the drawing]

The drawing is a block diagram showing one embodiment of the present invention. 1...First amplifier, 2...Second amplifier, 5
...Reversible electroacoustic transducer, 6...Transmission line,
7... Transmission/reception changeover switch, 91... First monostable multivibrator, 92... Second monostable multivibrator.

Claims (1)

[Claims] 1. In the first contact position, the reversible electroacoustic transducer is connected to the input of the first amplifier, and the output of the first amplifier is connected to the transmission line; A transmit/receive selector switch connects the transmission line to the input of the second amplifier and connects the output of the second amplifier to the reversible electroacoustic transducer; a first monostable multivibrator into which an audio signal is input via a first waveform shaping circuit and outputs a first logic signal among the binary signals while the audio signal is present; The signal from the acoustic transducer is the second
is inputted via the waveform shaping circuit, and the first
Its operation is controlled by the output of the first monostable multivibrator, and during a period in which the output of the first monostable multivibrator is not in the first logic, the reversible electroacoustic transducer generates a voice during normal conversation. A second monostable device in which when a pulse voltage having a sufficiently larger peak value than the signal is output, the output logic is inverted and changes from the second logic to the first logic and returns to the second logic after a predetermined time. a multivibrator, and a pulse voltage while the output logic of this second monostable multivibrator is at the first logic, when the transmitting/receiving selector switch is at the second contact position, the output logic of the second monostable multivibrator is set to the first contact position. and a contact switching circuit that changes the first contact position to a second contact position when the first contact position is present.