JPH0136370Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a transceiver that modulates audio signals and enables mutual communication.

A conventional transceiver was constructed as shown in FIG. 1, for example. In the transceiver shown in FIG. 1, an audio signal output from a microphone is amplified by a microphone amplifier 1 and supplied to an FM transmitter 3 via a signal changeover switch 2. The configuration is such that it is supplied to the power source and connected to the power supply line via a coupling capacitor. Note that 5 is a power transformer. The FM signal on the power supply line is supplied to a bandpass filter 7 through a coupling capacitor and a receiving transformer 6, and the output of the bandpass filter 7 is supplied to an FM receiver 8 for reception, and demodulation from the FM receiver 8 is performed. The output is amplified by a power amplifier 9 and then supplied to a speaker. On the other hand, the output of the handset on/off detector 10 that detects the on/off state of the handset is supplied to a gain switching circuit 11 to switch the gain of the power amplifier 9 according to the state of the handset.
The output of 0 is supplied to the tremolo control circuit 12, and the output of the tremolo control circuit 12 is supplied to the tremolo signal oscillator 1.
The tremolo signal is supplied to signal changeover switch 2.
supply to. The detection output of the FM receiver 8 which received the specified FM signal is supplied to the signal changeover switch 2 as a switching signal, and the tremolo control circuit 1
2 as a control signal to stop tremolo oscillation.

First, in a state where no FM signal is being received, there is no reception detection signal from the FM receiver 8 to the tremolo control circuit 12, and when the receiver is picked up in this state, the tremolo control circuit 12 is sent to the receiver on/off detector 10.
The tremolo oscillator 13 is controlled to an oscillating state in response to the output of the tremolo oscillator 13. The oscillation output of the tremolo oscillator 13 is supplied to the FM transmitter 3 via the signal changeover switch 2, where it is FM modulated and output from the transmission transformer 4. When a specified FM signal is received in this state, the FM receiver 8 demodulates the received FM signal, amplifies the power, and outputs the signal. On the other hand, a detection output is generated from the FM receiver 8, and the oscillation of the tremolo oscillator 13 is stopped via the tremolo control circuit 12.
The signal changeover switch 2 is switched to the microphone amplifier 1 side, and the output of the microphone amplifier 1 is FM modulated by the FM transmitter 3 and output to the power supply line via the transmission transformer 4 and the coupling capacitor. Therefore, mutual communication can be performed.

Further, when an FM signal is received while the handset is placed, the detection signal of the FM receiver 8 causes the tremolo oscillator 1 to be activated via the tremolo control circuit 12.
3 is stopped, and the signal changeover switch 2 is switched to the microphone amplifier 1 side. The received FM signal is demodulated by the FM receiver 8, amplified by the power amplifier 9, and then supplied to the speaker. At this time, depending on the state of the handset, the power amplifier 9 is controlled by the gain switching circuit 11 to have a low gain when the handset is picked up, and a high gain when the handset is placed. Further, the audio signal via the signal changeover switch 2 is FM modulated by the FM transmitter 3 and output to the power supply line via the transmission transformer 4 and the coupling capacitor, thereby establishing a mutual communication state.

In a conventionally configured transmitter/receiver, FM
The transmitting frequency ₁ of the transmitter 3 and the receiving frequency ₂ of the FM receiver 8 are each fixed. For example, the transmitting frequency ₁ of the transmitter A, the receiving frequency ₁ of the transmitter/receiver B, and the receiving frequency 2 of the FM receiver 8 are fixed.
The transmission frequency is fixed at ₁ and the reception frequency is fixed at ₂ , respectively, and it is necessary to configure transmitters and receivers A and B as shown in FIG. 2, which has the disadvantage that it is difficult to expand the system. Furthermore, even if the system is expanded, the transmitter/receivers A, B ₁ and B ₂ as shown in FIG.
between transmitter/receiver A and B ₁ , and between transmitter/receiver A and
Although it is possible to communicate with B ₂ , the transmitter/receiver
When B ₁ and B ₂ transmit at the same time, the transceiver A has the drawback that it cannot receive either, and it is also impossible to communicate with each other between the transceivers B ₁ and B ₂ . That is, when transmitting and receiving data using two carrier waves, it has been impossible to communicate with any two terminals among three or more terminals.

The present invention has been made in view of the above, and an object of the present invention is to provide a transceiver that eliminates the above-mentioned drawbacks.

The present invention aims to achieve the above-mentioned object, and its configuration consists of a transmitter configured so that the transmission frequency can be switched to different frequencies ₁ and ₂ , and a configuration configured so that the reception frequency can be switched to different frequencies ₁ and ₂ . If you switch to transmitting mode from a state where it is not receiving, the transmitting frequency is set to ₂ and the receiving frequency is set to ₁ , and if you switch to transmitting mode from a state where frequency ₂ is being received. The transmitting frequency is set to ₁ , and the receiving frequency is set to ₂ , and when the transmitter transmits at frequency ₂ , it transmits a control signal until the receiver receives the signal at frequency ₁ , and the receiver When a signal of frequency ₂ including a control signal is being received and the control signal disappears before starting a transmission operation, transmission is disabled.

The present invention will be explained below with reference to examples.

FIG. 4 is a block diagram showing one embodiment of the present invention.

The audio signal from the microphone is sent to microphone amplifier 1.
The output of the transmitter 3 is amplified and supplied to the FM transmitter 3 via the signal changeover switch 2.
Power transformer 5 via a coupling capacitor
It is configured to be placed on the power line of the The FM signal on the power supply line is supplied through a coupling capacitor and a reception transformer 6 to a bandpass filter 7A capable of switching the center frequency, and the output of the bandpass filter 7A is supplied to an FM receiver 8 for reception.
The output of the FM receiver 8 is supplied to a power amplifier 9 via an adder 24 to be amplified and then supplied to a speaker.

On the other hand, 14 is a switching circuit that switches the carrier frequency of the transmitter 3, the local oscillation frequency of the receiver 8, and the center frequency of the bandpass filter 7A.
The switching circuit 14 includes a rising edge detection section and a latch, and detects the rising edge of the AND gate 22 and latches (sets) it.
It is configured to be reset by hanging up the handset. 15 is a control signal generator, and the generated output of the control signal generator 15 is supplied to the signal changeover switch 2 via a bandpass filter 16, where it is switched with the output of the microphone amplifier 1 and supplied to the transmitter 3. It is configured.

The detection signal received by the receiver 8 is supplied to the AND gate 22 via the inverter 21, the output of the handset on/off detector 10A when the handset is on is supplied to the AND gate 22, and the output of the AND gate 22 is connected to the switching circuit. 14 as a switching signal. Further, the output of the inverter 21 and the output of the receiver on/off detector 10A when the receiver is on are supplied to an AND gate 20, and the output of the AND gate 20 is supplied to the control signal generator 15 as a control signal.

The received output of the receiver 8 is passed through a bandpass filter 16.
The output of the control signal detector 18, the detection output of the receiver 8, and the output of the receiver on/off detector 10A when the receiver is off are connected to an AND gate. 23, and the output of the AND gate 23 is supplied to the tremolo oscillator 13 as a control signal. The oscillation output of the tremolo oscillator 13 is supplied to an adder 24 and is configured to be added to the received output of the receiver 8.

The output of the control signal detector 18 and the detection output of the receiver 8 are supplied to a transmission stop signal generator 19, and the output of the transmission stop signal generator 19 is supplied to the transmitter 3 to stop transmission. be. The output of the handset on/off detector 10A when the handset is off is supplied to a gain switching circuit 11, and the gain of the power amplifier 9 is controlled by the output of the gain switching circuit 11.

In one embodiment of the present invention configured as described above, the transmitting frequency is set to ₁ , the receiving frequency is set to ₂ , and the transmitter/receiver C, D,
The operation will be explained using an example in which mutual communication is performed using E.

Normally, the receiver is in a receiving ready state waiting for a call from the other party's transceiver, and this state is as shown in FIG. 5a.

First, when calling the other party's transceiver, receiver 8
has no receive input. In this state, pick up the receiver. Handset on/off detector 10A generates an on output and AND gate 20 opens its gate. On the other hand, since the receiver 8 is not generating a detection output, the output of the inverter 21 is at a high potential, and the control signal generator 15 is driven to output a control signal. In addition, since the output of the inverter 21 is at a high potential, the signal changeover switch 2 is switched to the bandpass filter 16 side, and the control signal output from the control signal generator 15 is transferred to the bandpass filter 16 and the signal changeover switch 2.
is supplied to the transmitter 3 via. The AND gate 22 also generates a high potential output, and the switching circuit 14 changes the carrier frequency of the transmitter 3 to ₂ , the oscillation frequency of the local oscillator of the receiver 8 to a frequency corresponding to reception frequency ₁ , and the bandpass filter 7A. The center frequency of is switched to ₁ (Figure 5b). As a result, the carrier frequency ₂ is FM-modulated by the control signal from the control signal generator 15 supplied via the bandpass filter 16 and the signal changeover switch 2, and is output from the transmitter 3. It is placed on the power line via a capacitor. The transceiver that responds to this call transmits on frequency ₁ . 5b shows a state in which the transceiver C is making a call, and FIG. 5c shows a state in which the transceiver D responds to a call from the transceiver A. The frequency ₁ transmission sent out from the transceiver that responded to the call is because the center frequency of the bandpass filter of the transceiver that made the call is set to ₁ , so the signal from the transceiver that responded is transmitted to the receiving transformer 6. , are received by the receiver 8 via the bandpass filter 7A. As a result of this reception, the receiver 8 generates a detection output indicating that it has received the FM signal of frequency ₁ , and the output of the inverter 21 becomes a low potential. Therefore, the output of the AND gate 20 becomes a low potential, and the control signal generator 15 stops generating the control signal. At the same time, the signal changeover switch 2 is switched to the microphone amplifier 1 side by the output of the inverter 21. Therefore, a state of mutual communication is established.

Next, the transmitter/receiver on the side receiving the call will be explained.

The transceiver (transceiver D in Figure 5 b and c) that responded in response to the oscillation output of the transceiver is in the receiving state with _{the receiving frequency 2 ,}
Receiver 8 changes the frequency by receiving the FM signal.
It generates a detection output when the FM signal of ₂ is received, and also generates a reception output. This received output is supplied to the power amplifier 9 via the adder 24 and also supplied to the control signal detector 18 via the bandpass filter 17, and the control signal detector 18 generates a control signal. When the handset is placed in this state, each input of the AND gate 23 is at a high potential, the AND gate 23 generates a high potential output, and the tremolo oscillator 13 generates a tremolo signal, which is amplified by the power amplifier 9. The signal is then supplied to the speaker. When the handset is picked up, the signal supplied from the handset on/off detector 10A to the AND gate 23 becomes a low potential, the tremolo oscillator 13 stops oscillating, and the gain switching circuit 11 lowers the gain of the power amplifier 9. This is to lower the level and make it easier to hear when receiving with a handset. After that, they will be in a mutual conversation state.

On the other hand, the operation of the other transceiver (transceiver E in FIGS. 5b and 5c) is as follows. The other transmitters are in the state of transmitting frequency ₁ and receiving frequency ₂ , and are in the calling state by detecting the control signal of frequency ₂ from the calling side transceiver (transceiver C in Figure 5 b, c). When the calling side transmitter/receiver receives the response signal, it stops sending the control signal as described above, and mutual communication is performed with the responding side transmitter/receiver (transceiver D in FIGS. 5b and 5c). Therefore, the calling side transceiver stops sending the control signal of frequency ₂ . When the control signal of frequency ₂ disappears, it is detected by the control signal detector 18 via the band pass filter 17, and the transmission stop signal generator 19 outputs a transmission stop signal to the transmitter 3. Therefore, the transmitter 3 stops transmitting. As a result, if mutual communication between the calling side transceiver and the responding side transceiver starts, the other transceiver will not be able to transmit. This also applies when you pick up the handset of another transmitter/receiver. Therefore, mutual communication between the calling transceiver and the responding transceiver is not interrupted by other transceivers. Note that the other transceivers receive the transmission signal from the calling transceiver.

As is clear from the above effects, when two carrier waves are used and the system is extended to three or more transceivers, mutual communication is possible between any of the transceivers.

In addition, in one embodiment of the present invention described above, the FM
Although the case of a carrier-type wireless interphone has been described as an example, the same configuration can be applied to a general transceiver.

As explained above, according to the present invention, two carrier waves are used, and normally, for example, the transmitting frequency is set to ₁ and the receiving frequency is set to ₂ , and when the first call is made, the transmitting frequency is set to ₂ and the receiving frequency is set to ₁ . In a system of three or more transceivers, mutual communication is possible between any terminal, and by stopping the calling side's control signal upon reception of a response signal, transmission of a transceiver other than the one currently communicating with the other is possible. Since the communication is stopped, the communication between the two transmitters and receivers can be reliably carried out.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of a conventional transceiver, Figs. 2 and 3 are explanatory diagrams showing the state of telephone communication in the conventional transceiver shown in Fig. 1, and Fig. 4 is a block diagram showing the configuration of a conventional transceiver. FIG. 5 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 1...Microphone amplifier, 2...Signal changeover switch, 3...Transmitter, 4...Transmission transformer, 5...
Power transformer, 6... Receiving transformer, 7A... Band pass filter, 8... Receiver, 9... Power amplifier, 10A... Handset on/off detector, 11...
Gain switching circuit, 13...Tremolo oscillator, 14
...Switching circuit, 15...Control signal generator, 16 and 17...Band pass filter, 18...Control signal detector, 19...Transmission stop signal generator.

Claims (1)

[Scope of utility model registration request] Equipped with a transmitter whose transmission frequencies can be switched to different frequencies ₁ and ₂ , and a receiver whose reception frequencies can be switched to different frequencies ₁ and ₂ , it is possible to switch from a non-receiving state to a transmitting operation. If the transmit frequency is ₂ and the receive frequency is
₁ , and if you switch from receiving frequency ₂ to transmitting, the transmitting frequency will be set to ₁ , and the receiving frequency will be set to ₂ , and when the transmitter transmits at frequency ₂ , the receiver will The control signal is transmitted until the signal of frequency ₁ is received, and when the control signal disappears before moving to the transmission operation while the receiver is receiving the signal of frequency ₂ including the control signal, the control signal is transmitted. A transmitter/receiver characterized in that the transmitter/receiver is configured such that the transmitter/receiver becomes disabled.