JPH01106532A - Voice communication equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention includes 1. The present invention relates to an audio communication device that transmits an audio signal and a control signal via the same transmission path.

[Prior Art] In conventional digital cell call communication, a binary data control signal for controlling communication and an audio signal for communication are transmitted in a time-division manner using the same transmission path.

Figure 4 shows a timing diagram showing an example of this communication.
It is The sending side first calls the receiving side and sends a communication start data signal 31 for starting communication, then sends a voice signal 32, and then, when the communication ends, sends a communication end data signal 33. Here, the communication start data signal 31 and the communication end data signal 33 are, for example, 8-bit binary data signals, and each signal 34, 33
are signals representing specific codes such as "zotobi", "tototbi", etc., respectively. On the other hand, when the receiving side receives the communication start data signal 31, it turns on an audio output switch that switches whether or not to output the received audio signal 32 to audio output devices such as speakers, earphones, and headphones. The audio signal 32 received following the communication start data signal is output to the audio output device. Next, when the communication end data signal 33 is received at the end of the communication, after turning off the audio output switch, the receiving side recognizes that the communication has ended and receives the communication start data signal 31. Performs processing on the receiving side, such as processing to prepare for.

[Problems to be Solved by the Invention] However, in the conventional communication system described above, the audio output switch is turned off after receiving the communication end data signal 33, so that the communication is a binary data signal. There is a problem in that the end data signal 33 is output as a sound to the audio output device, and the operator therefore hears the data signal 33 as a harsh sound.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an audio communication device that does not output a control signal indicating the end of communication as a sound to an audio output device when communication of audio signals ends.

[Means for Solving the Problems] The present invention provides an audio communication device that transmits an audio signal and a control signal through the same transmission path, in which a control signal of a predetermined level that continues for a predetermined time at the end of transmission of the audio signal is transmitted. A receiver comprising: a transmitting device that transmits; a switch that switches whether or not to output the audio signal to an audio output device; and a control means that turns off the switch when receiving the control signal transmitted from the transmitting device. It is characterized by being equipped with a device.

By configuring as described above, after the transmitting device transmits a control signal of a predetermined level that continues for a predetermined time at the end of transmission of the audio signal, the control means of the receiving device receives the control signal transmitted from the transmitting device. When the control signal is received, the switch is turned off.

[Embodiment] FIG. 1 is a block diagram of a digital cell call communication system that is an embodiment of the present invention.

In this communication system, the transmitter outputs an audio end signal 34 that continues for a predetermined period of time 10 and has an H level of a binary data signal of +5V, for example, immediately before a communication end data signal 33 indicating the end of communication. On the other hand, when the receiving device receives the audio end signal 34, it turns off the audio output switch 25 and outputs the communication end data signal 33 to the speaker 2.
It is characterized in that it stops being output to 7.

In the transmitting device 100 shown in FIG. 1, the audio input to the microphone 1 is converted into an audio signal and then output to the transmitter 5 via the amplifier 2, the b side of the changeover switch 3, and the F Mt & modulator 4. , the transmitter 5 outputs an FM radio signal of the audio signal via the antenna 6.

The control circuit 10 includes a changeover switch 3 of the transmitter 100,
A control circuit that controls the operation of the FM converter EIII unit 4 and the transmitter 5, and is used as, for example, a central processing unit that performs control processing, a ROM that stores control programs, and a working area during control processing. Consists of RAM. One end of each of a communication start switch 2 for instructing the start of communication and a communication end switch 12 for instructing the end of communication are connected to the control circuit IO, and the other end of each switch 11 and +2 is connected to ground. connected to. When the communication start switch 11 is turned on, the control circuit 10 switches the changeover switch 3 to the a side and sets the FM modulator 4 to FS.
Set to K signal mode, turn on the power of the transmitter 5, and instruct the signal generating circuit 13 to output the communication start data signal 31 for starting communication after calling the receiving device 200, and start the communication. After transmitting the data signal 31, the switch 3 is switched to the b side, and the FM modulation 'a' is
4 is set to the audio F'M signal mode, whereby an audio signal can be transmitted to the receiving device 200 using the microphone t. Next, when the communication end switch 12 is turned on, the control circuit IO switches the changeover switch 3 to the a side, sets the FM modulator 4 to the FSK signal mode, and sends the audio end signal 34 indicating the end of the audio signal. The signal generation circuit 13 is instructed to output the communication end data signal 33 indicating the end of communication, and after each of the above signals 34 and 33 is transmitted, Turn off the power of machine 5.

When the signal generating circuit t3 is instructed by the control circuit 10 to output the communication start data signal 31, the audio end signal 34, and the communication end data signal, the signal generating circuit t3 generates, for example, an 8-bit binary digital signal of "ttotobi". The data signal, a level signal of a predetermined time to, for example, 20 milliseconds, and an 8-bit binary data signal of 1 to 2 are output to the FM modulator 4 via the a side of the changeover switch 3. .

In the FSK signal mode, the FM modulator 4 performs FSK modulation on the carrier wave with a binary data signal or an H level signal input from the signal generation circuit 13, and generates a PSK signal having a frequency rl and a frequency f2 higher than the frequency [1]. The signal is output to the transmitter 5, and on the other hand, in the audio FM signal mode, the carrier wave is the audio signal input from the microphone 1 through the amplifier 2.
14, and centering on the frequency (fl+f2)/2,
An audio FM signal FM-modulated with a maximum frequency deviation of ±([2-41)/2] is output to the transmitter 5. Regarding the frequency modulation device for FSK signals and audio signals corresponding to this F'M modulator 4, the name of the invention is "Frequency Modulation Device", which was filed for a patent on October 19, 1988 by the present applicant.
This is disclosed in detail in the specification.

The transmitter 5 transmits the FSK signal or the audio PM multiplied signal input from the FM modulator 4 to the receiving device 200 via the antenna 6 using a carrier wave having a predetermined radio frequency.

In the receiving device 200 of FIG. 1, the signal received via the antenna 20 is subjected to predetermined processing such as amplification and conversion to an intermediate frequency in the receiver 21, and then is FM!
[! It is output to the II unit 22. The F'M demodulator 22 performs FM demodulation on the input signal and outputs the demodulated signal to the signal detection circuit 23 as well as to the speaker 27 via the audio output switch 25 and the amplifier 26.

The signal detection circuit 23 detects whether the input signals are the communication start data signal 31, the voice end signal 34, and the communication end signal 33. Signal detection circuit 23
When the control circuit 24 detects the communication start data signal 31
Then, when the audio end signal 34 is detected, the audio output switch 25 is turned off via the control circuit 24, and further, when the communication end data signal 33 is detected, the detection signal is turned on. The signal is output to the control circuit 24, and the control circuit 24 recognizes that the communication has ended and performs processing on the receiving device, such as processing to prepare the communication start data signal 31 for receiving. Note that when the communication end data signal 33 cannot be detected after a predetermined time, for example 5 milliseconds, after detecting the H level signal for the predetermined time to, the control circuit 24 determines that the H level signal is an erroneous signal due to noise. Then, turn on the audio output switch 25. Here, the signal detection circuit 23 detects the time Lθ±20
%, it is determined that the audio end signal 34 has been received, and the detection signal is output to the control circuit 24.

The control circuit 10 and signal generation circuit 13 of the transmitting device 100, and the signal detection circuit 23 and control circuit 24 of the receiving device 200 are each preferably made of Hitachi's new HD6.
It is composed of a 37BO1 type CPU.

The operation of the communication system configured as described above will be explained with reference to the timing charts of FIGS. 2 and 3.

First, as shown in FIG. 2, in the receiving device 200,
When the voice signal 32, the voice end signal 34, and the communication end signal 33 are received following the communication start data signal 31,
When the signal detection circuit 23 detects the communication start data signal 31, the audio output switch 25 is turned on via the control circuit 24, whereby the subsequently received audio signal 32 is transmitted via the audio output switch 25 and the amplifier 26. It is output to the speaker 27. Next, when detecting the voice end signal 34, the signal detection circuit 23 turns off the voice output switch 25 via the control circuit 24, whereby the communication end data signal 33 received following the voice end signal 34 is output to the speaker. 27 is prevented from being output. Further, when the communication end data signal 33 is detected, the detection signal is output to the control circuit 2.4, and the control circuit 24 recognizes that the communication has ended and prepares to receive the communication start data signal 31. Performs processing of the receiving device such as processing to set the status.

Further, as shown in the timing chart of FIG. 3, while the audio signal 32 is being received, the transmitting device! If a signal of level 1] that continues for a predetermined period of time 10 and is a noise that is not transmitted from 00 to When the switch 25 is turned off, but the communication end data signal 33 cannot be detected after a predetermined period of time, for example 5 milliseconds, as shown in FIG. Determine that the 4-level signal is an erroneous signal due to noise,
Turn on the audio output switch 25. Other operations are similar to those shown in FIG. 2 above. As described above, when a communication end data signal is not received within a predetermined time after receiving a continuous H level signal for a predetermined time of 10,
By restoring the audio output switch 24 from OFF to ON, even if a continuous H level signal is received for the predetermined time period to, which is noise not transmitted from the transmitter 100, communication is terminated and the audio signal is output. It should be possible to prevent malfunctions such as inability to receive data.

As explained above, the voice end signal 34 for a predetermined time period to which has a binary data signal (■) level of +5■, for example, is outputted to the direct curve of the communication end data signal 33, while the receiving device There is an advantage that when the voice end signal 34 is received, the voice output switch 25 is turned off, thereby preventing the communication end data signal 33 from being output to the speaker 27, which is annoying to the operator.

In the above embodiment, the transmitting device 100 transmits the communication end data signal 33 following the voice end signal 34, but the present invention is not limited to this, and transmits only the voice end signal 34,
When the receiving device 200 receives the audio termination signal 34, the audio output switch 25 may be turned off and a predetermined process for terminating the communication may be performed. In this case, the above third
Malfunctions caused by noise signals, as described with reference to the timing chart in the figure, cannot be avoided.

In the above embodiment, the audio end signal 34 continues for a predetermined time of 10! Although the signal is a four-level signal, the signal is not limited to this, and may be a signal of a predetermined level, such as an L level or an intermediate level between an H level and an L level, which continues for a predetermined period of time.

Although the above embodiment describes an example of a one-way wireless communication system, the present invention is not limited to this, and can be widely applied to other communication systems such as full-duplex communication, half-duplex communication, and wired communication systems. can do.

[Effects of the Invention] As described in detail above, according to the present invention, after the transmitting device transmits a control signal of a predetermined level that continues for a predetermined period of time at the end of transmission of an audio signal, the control means of the receiving device controls the control signal from the transmitting device. By turning off a switch that selects whether or not to output the audio signal to the audio output device when the transmitted control signal is received, the control signal indicating the end of the communication becomes unpleasant when the audio signal communication ends. This has the advantage that it is possible to prevent the sound from being output to the audio output device as a loud sound.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a digital cell call communication system that is an embodiment of the present invention, FIGS. 2 and 3 are timing charts showing the operation of the communication system of FIG. 1, and FIG. 4 is a conventional digital cell call system. 3 is a timing chart showing the operation of the communication system. 1... Microphone, 2... Amplifier, 3... Changeover switch, 4... FM modulator, 5... Transmitter, 6... Antenna, 10... Control circuit, 11... - Communication start switch, 12... Communication end switch, 13... Signal generation circuit, 20... Antenna, 21... Receiver, 22-F Mffl adjuster, 23... Signal detector, 24 ...Control circuit, 25...Audio output switch, 26...Amplifier, 27...Speaker, 31...Communication start data signal, 32...Audio signal, 33...Communication end data signal , 34... Audio end signal, 100... Transmitting device, 200... Receiving device. Patent distributor Furuno Electric Co., Ltd. agent Patent attorney Aohaku Ao and 2 others

Claims (1)

[Claims] (1) In an audio communication device that transmits an audio signal and a control signal via the same transmission path, a transmitter that transmits a control signal at a predetermined level that continues for a predetermined period of time when the transmission of the audio signal ends; Audio communication characterized by comprising a receiving device having a switch for switching whether or not to output to an audio output device, and a control means for turning off the switch when receiving the control signal transmitted from the transmitting device. Device.