JPS6021664A - Communication system - Google Patents

Abstract

PURPOSE:To prevent the generation of noise by introducing repetitively a start signal at the start of operation when a press-to-talk switch is operated so as to inhibit the transmission state until the reception of the said start signal is finished. CONSTITUTION:When the press-to-talk switch 9 of a transmitter 3 is operated, a processing circuit 13 generates continuously for plural number of times the start signal subject to pulse code modulation and transmits it to a receiver 4 from a light emitting element 14. Then the voice from a microphone 8 is modulated by the circuit 13 and the result is transmitted from the element 14 as a voice signal modulation light. The receiver 14 receives (15) the optical signal from the transmitter 3, converts it into an electric signal and inputs it to a reception circuit 16. The circuit 16 detects the start signal and sets an FF21 and also inputs the detecting signal to a processing circuit 17. A transistor TR24 is made conductive by the output of the FF21 so as to drive a relay 26 and change over contacts 27. After the transmission of a start signal is finished, the circuit 17 transmits the voice signal demodulated by the circuit 16 through a line 7 to the receiver 6 and outputs the voice signal from the speaker of the receiver 6.

Description

TECHNICAL FIELD The present invention relates to a communication system that includes at least one pair of transmitting/receiving devices, such as an intercom, and is capable of transmitting and receiving audio signals.

BACKGROUND ART FIG. 1 is a system diagram that forms the basis of the present invention and serves to explain the prior art. at least one pair of transmitting/receiving devices 1
．． 2 is equipped with a transmitter 3 and a receiver 4, and the other transmitting/receiving device 2 is equipped with a transmitter 5 and a receiver 6, and these receivers 4, 6 are connected to a line 7. The transmitter 3, which is connected to each other by MR, has a micropon 8.
and a breath talk switch 9, and the transmitter 5 is equipped with a microphone 10 and a breath talk switch 1.
1 is provided.

In the prior art, as shown in FIG. 2 (1), the time t1
When the breath talk switch 9 is operated, a start signal that lasts for a time W1 is emitted as an infrared light, as shown in FIG. 2 (2), and is received by the receiver 4. In addition, when the breath talk switch 9 is released at time t2, Fig. 2 (3)
After that, a termination signal lasting for a time W2 is derived, as shown in . The start and end signals are transmitted several times in succession and have more than a few words in order to ensure that they can be received by the receiver 4. These start signals and end signals are received by the receiver 4, and as shown in FIG. 2 (4), the receiver 4 enters the transmitting state, for example, at time t3 when the first start signal is detected. Further, after time t2, at time t4 when, for example, the first end signal among the end signals sent out multiple times is detected, the state enters the receiving operation state, and the state becomes such that the audio signal from the transmitting/receiving device 2 can be audible. .

In such a prior art, a start signal is sent from the receiver 4 to the receiver 6 during the period from time t3 to time W11, and is converted into sound by the receiver 6. It's still time t2
At the time W21 of ~t4, the end signal is also sent to the receiver 4.
6 and is converted into sound. In this way, the start signal and end signal sent from the receiver 4 are audible as noise in the receiver 6, and the purpose is to prevent such noise as much as possible. An object of the present invention is to provide an improved communication system that prevents 4-M-(/J'5e generation as much as possible.

Embodiment FIG. 3 shows two tips for transmitter 3 according to an embodiment of the present invention. Microphone 8 and breathtalk switch 9
The output from is input to a processing circuit 13 implemented by a microcomputer or the like. When the breath talk switch 9 is operated, the processing circuit 13 successively generates a ζ code modulated start signal a plurality of times and sends it from the light emitting element 14 to the receiver 4. During the operation period of the breath talk switch 9, the sound from the microphone 8 is modulated by the processing circuit 13, and the light emitting element 1 is modulated by the processing circuit 13.
4 as an audio signal.

FIG. 4 is a block diagram of the receiver 4. Optical signals such as infrared rays from the transmitter 3 are received by the light receiving element 15 and received by the receiving circuit 16, which is connected to the receiving circuit 16V (related to which is connected the processing circuit 17. The processing circuit F is connected to the speaker 18. is connected, and the sound 4+ signal from the receiver 6 of the other transmitting/receiving device 2 via the line 7 is converted into sound (transmitted at time ti as shown in FIG. 5(1)). When the breath talk switch 9 is suppressed, the processing circuit 13 of the transmitter 3 pulse-code modulates and derives the start signal multiple times over a period of time W3, as shown in FIG. 5(2). In the receiver 4, the receiving circuit 16 detects the first starting signal among the plurality of starting signals over this time W3, and derives the signal shown in FIG. 5(3) on the line 20. This line 20
The signal sets the flip-flop 21. The signal on line 20 lasts the time after detecting the start signal until the end of the transmission of that start signal. The set output of the flip-flop 21 is applied to one input of an AND gate 22. The set output of this flip-flop 21 is 2 (shown in FIG. 5(6)). Has molding. The receiving circuit 16 provides a signal to the AND gate 22 via the inverting circuit 23. The output waveform of the inverting circuit 23 is the fifth
As shown in FIG. 7, a signal is derived that is at a low level from time t2 when the start signal is detected to time t3 when the start signal ends. The AND gate 22 derives a signal that becomes a zero level after time t3, as shown in FIG. 5(8). The output of the AND gate 22 turns on the transistor 24 after time t3, thereby exciting the relay coil 26 of the relay 25. By exciting the relay coil 26, the switching mode of the relay switch 27 changes. After time t3, the processing circuit 17 demodulates the audio signal sent from the transmitter 3 and supplies it to the receiver 6 of the other transmitting/receiving device 2 via the line 7 from the receiving circuit 16.

When the transmitter 3 finishes transmitting and releases the breath talk switch 9 at time t4, the processing circuit 13 of the transmitter 3
sends the end signal multiple times over time W4 up to time t6. This termination signal is pulse code modulated. In the receiver 4, the 1-1 receiving circuit 16 detects, for example, the first termination signal among the termination signals sent out a plurality of times, and after that time t5, a pulse having the waveform shown in FIG. 5(5) is transmitted from the line 28. Derive. This resets the flip-flop 21 and the AND gate 2
The output of 2 becomes low level. The output from the inverting circuit 23 becomes low level during the time period t5 to t6. In this way, the transistor 24 is interrupted at one point, and the relay coil 26
is demagnetized. Therefore, the switching mode of the relay switch 27 returns to its original state. That's no good, the receiving operation status,
1, and the audio Iq from the receiver 6 of the transmitter/receiver 7g device 2 via the line 7 can be converted into sound by the processor t1 old circuit 17 through the speaker 18.

As another embodiment of the present invention, a plurality of three or more transmitting/receiving devices may be used, in which case, for example, the transmitter 3 is provided with an input means 28 having a plurality of push buttons, etc., as shown in FIG. It may be configured such that the transmitting/receiving device that is provided and the transmitting/receiving device with which to communicate can be selected.

As another embodiment of the present invention, the transmitter 3 to the receiver 4 not only transmits using infrared light;
Radio waves may be used, or the connection may also be made using lines - these modifications are to be interpreted as falling within the scope of the following claims.

Effects As described above, according to the present invention, after the start signal is detected, the transmitting operation state is not set until the reception of the start signal is completed, so that the start signal is audible as noise in other transmitting/receiving devices. This will be prevented. This allows smooth transmission and reception operations.

[Brief explanation of the drawing]

Fig. 1 is an overall system diagram of the communication system that forms the basis of the present invention and is for explaining the prior art, Fig. 2 is a waveform diagram for explaining the operation of the prior art, and Fig. 3 is one implementation of the present invention. FIG. 4 is a block diagram of a transmitter 3 as an example, FIG. 4 is a block diagram of a receiver 4 as an embodiment of the present invention, and FIG. 5 is for explaining the operation of the embodiment shown in FIGS. 3 and 4. FIG. 1.2... Transmitting/receiving device, 3, 5... Transmitter, 4, 6
...Receiver, 8...Microphone, 9.10...
Breath talk switch, 13.17...processing circuit, 1
4... Light emitting element, 15... Light receiving element, 16... Receiving circuit, 18... Speaker, 21... Flip-flop, 22... AND gate, 25... Relay agent Patent attorney Saikyo Kei Part Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] At least one pair of transmitting/receiving devices is provided, and at least one of each transmitting/receiving device includes a transmitter that generates an audio signal, and a transmitter that receives the audio signal from the transmitter and transmits the audio signal to the other transmitting/receiving device. a receiver that performs a transmitting operation of transmitting a voice signal from the other transmitting/receiving device through a switching means, and a receiving operation of converting an audio signal from the other transmitting/receiving device into sound through the switching means; The EMS receiver includes a switch and a signal generating means that repeatedly outputs a start signal at the initial stage of operation when the breath talk switch is operated, and the EMS receiver is configured to generate a signal after emitting the start signal by the switching means. , a communication method characterized in that the transmitting operation state is not set until the reception of the start signal is completed.