JPH10229345A - Squelch control method for radio communication system, radio equipment and remote controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain communication without hindrance, by not affecting the remote controller, even at a weak electric field strength by controlling a speech output, based on a squelch signal received by the remote controller and applying squelch control to each remote controller. SOLUTION: In the case of receiving no radio wave by the radio equipment, an audio output and a noise component output of a demodulator section 13 include only a noise components, an output of a noise amplifier section 15 is a maximum, a tone signal of a tone signal generating section 16 is converted by a squelch signal conversion section 17 and outputted as a maximum level. The tone signal passes through a squelch signal amplifier section 18, is synthesized with an audio signal output (noise in this case) of an audio signal synthesis section 19, and the result is outputted to a line. The remote controller receiving the signal controls the speech output based on the received squelch signal, then squelch control is applied to each remote controller. Thus, the squelch control is applied individually to each remote controller.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squelch control method in a radio communication system such as a disaster prevention radio system, and a radio device and a remote control device constituting a radio communication system for performing the method.

In a conventional wireless communication system having a squelch function, when a received electric field from a communication partner station is equal to or lower than a squelch sensitivity level, squelch control is performed and communication cannot be performed. This is a problem in the case of communication. That is, it is necessary to perform important communication in an emergency or the like without any trouble even if the communication is a weak electric field. However, lowering the overall squelch sensitivity level of the wireless communication system to a particular remote control that requires communication has undesirable effects on other remote controls. Therefore, there is a need for a squelch control method that enables communication even in a weak electric field without affecting other remote control devices.

[0003]

2. Description of the Related Art Wireless communication systems such as disaster prevention wireless systems
For example, as shown in FIG.
A wireless device 1 including other devices and a transmission line 3₁~ 3
_nOne or more remote controls 2 for controlling through₁~
2_nAnd transmission line 3 ₁~ 3_nIs wired, microphone
(B) It is composed of lines such as carrier, optical carrier and cable carrier.
The wireless device 1 transmits FM (frequency conversion) to a wireless station such as a mobile device.
Wireless communication is performed by a key control method or the like. Thus, the wireless device 1
Is one or more remote control devices 2₁~ 2_nIs connected
And each remote control device 2₁~ 2_nTo the user
Call control and the like are performed. That is, each remote control device
2₁~ 2_nFrom a wireless station such as a mobile device through the wireless device 1
A call is made between.

Conventionally, in such a wireless communication system, squelch control has been performed on the wireless device 1 side. Mu The squelch control, when the received electric field of the radio communication with the radio station is less weak squelch sensitivity level, a call signal transmitted from the wireless device 1 to each remote control device 2 ₁ to 2 _n in the wireless device 1 side It is something that will be done. This is F
In the case of the M system or the like, if the received electric field is a weak electric field, a large noise is involved, which hinders the remote control device 2 from intercepting a call.

In this conventional squelch control method, generally, a squelch sensitivity level for performing squelch control is preset to a fixed sensitivity on the wireless device 1 side. Therefore, it is impossible to adjust individually squelch sensitivity level for each remote control device 2 ₁ to 2 _n, squelch sensitivity level which is set has become common to 2 ₁ to 2 _n all the remote control device.

[0006]

The problem with this method is that
If the reception electric field from the communication partner station is equal to or lower than the squelch sensitivity level, communication becomes impossible, and if the communication is important communication, it becomes a serious obstacle such as disaster prevention. It is necessary to perform important communication in an emergency or the like without any trouble even if the electric field is weak.

For this reason, a method for controlling the squelch connection / disconnection of the wireless device 1 by the remote control device 2 is provided. That is, a method is provided in which the wireless device 1 is provided with a function of connecting / disconnecting the squelch function by a control signal, and is connected / disconnected by a control signal from the remote control device 2 via a transmission line from a remote location. However, in this method, when the squelch function disconnection, the whole radio communication system remote controller 2 ₁ to 2 _n
Are no longer subject to squelch control. For this reason, when the remote control device 2 of a certain station needs to make a call with a weak electric field, the squelch function of the wireless device 1 is turned off. in it, it is all the other remote control device 2 ₁ to 2 _n
But would be an audio output as unpleasant noise, each remote control device 2 ₁ to 2 _n is greater discomfort if the intercepting whether there is addressed to itself call. In other words, the method of disconnecting / connecting the squelch function from the remote control device side is that when a plurality of remote control devices are connected to the wireless device, when one remote control device controls the squelch disconnection, the other remote control device is controlled. Is also output, which is problematic.

As described above, the conventional squelch control method is as follows.
There have been problems such as noise output to a remote control device other than the remote control device, and the inability to communicate under a weak electric field.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and enables squelch control for each remote control device individually so that communication can be performed without affecting other remote control devices even under a weak electric field. The purpose is to be able to perform without trouble.

[0010]

FIGS. 1 and 2 are diagrams for explaining the principle of the present invention. FIG. 1 shows a configuration example of a wireless device, and FIG. 2 shows a configuration example of a remote control device.

In FIG. 1, 11 is an antenna, 12 is a receiving section including a high-frequency amplifier, a local oscillator, an intermediate frequency amplifier and the like, and 13 is a demodulation section. The output of the demodulation unit 13 is input to the audio signal amplification unit 14 and the noise amplification unit 15. Reference numeral 16 denotes a tone signal generator used as a squelch signal, and reference numeral 17 denotes a squelch signal converter for level-converting the tone signal from the tone signal generator 16 into a signal corresponding to the noise output of the noise amplifier 15. The output of the squelch signal conversion unit 17 passes through the squelch signal amplification unit 18, is then combined with the audio signal from the audio signal amplification unit 14 by the signal synthesis unit 19, and is sent out to each line by the line distribution device 10. This allows
The tone signal converted to a level corresponding to the noise output of the demodulation unit 13 is transmitted as a squelch signal to a remote control device connected via a transmission line such as a wired line, a microcarrier line, an optical carrier line, and a cable carrier line. Will be.

In FIG. 2, reference numeral 20 denotes an audio signal filter which blocks a squelch signal and passes an audio signal.
The output is amplified to a required level by the audio amplifier 21,
The signal is input to the audio signal mute unit 22. The audio signal mute unit 22 has a function of an analog switch that controls a speaker output by a squelch signal. The output is amplified by a power amplifier 23 and then output to a speaker 24.

A squelch signal filter 25 blocks an audio signal and allows a squelch signal to pass therethrough. The output of the filter is input to a squelch sensitivity adjustment unit 26 for adjusting the sensitivity of the squelch signal. Further, the squelch signal is converted into a control signal for controlling the audio signal mute unit 22 by the squelch control unit 27, and the audio output from the speaker is controlled depending on the presence or absence of the output.

In order to solve the above-mentioned problems, a squelch control method for a wireless communication system according to the present invention includes a wireless device and at least one squelch device connected to the wireless device through a transmission line to remotely control the wireless device. In the wireless communication system configured by the remote control device, the wireless device generates a squelch signal corresponding to the strength of the squelch control noise component of the received radio wave, transmits the squelch signal to the remote control device through a transmission line, and The apparatus is characterized in that squelch control is performed for each remote control device by controlling a call output based on the received squelch signal.

The squelch signal is a tone signal in a transmittable band of a transmission line between the wireless device and the remote control device.
The strength can be changed according to the strength of the squelch control noise component of the received radio wave. This is because the noise component used for the squelch control of the wireless device has many high-frequency components and cannot be transmitted because it is out of the band of the transmission line as it is. It is converted and sent.

Further, the radio apparatus according to the present invention provides a squelch signal generating means (for example, a demodulation unit 13 or a demodulation unit 13) for generating a squelch signal corresponding to the strength of a squelch control noise component of a received radio wave.
A noise control unit, a tone signal generation unit 16, a squelch signal conversion unit 17, a squelch signal amplification unit 18, and the like) and a squelch signal generated by the squelch signal generation unit via a transmission line. (For example, a portion composed of the signal synthesizing unit 19 and the line distribution device 10).

The squelch signal generation means includes detection means (for example, a demodulation unit 13 and a noise amplification unit 15) for detecting the strength of a squelch control noise component of a received radio wave, and a transmission line between a wireless device and a remote control device. A tone signal generating means (for example, tone signal generating unit 16) for generating a tone signal within a transmittable band, and changing the strength of the tone signal according to the strength of the squelch control noise component detected by the detecting means. A squelch signal conversion unit (for example, the squelch signal conversion unit 17 or the like) for converting the signal into a squelch signal can be included.

Further, the above-mentioned radio apparatus is a signal synthesizing means for synthesizing a squelch signal and a received audio signal to simultaneously transmit a squelch signal and a received audio signal to one remote control apparatus via one transmission line. Signal synthesizing section 19).

Further, the remote control device according to the present invention includes an extraction means (for example, a squelch signal filter 25, a squelch sensitivity adjustment unit 26, a squelch control unit 17 and the like) for extracting a squelch signal from a signal received from a wireless device. Mute means (for example, an audio signal mute unit 22, a squelch control unit 27, etc.) for muting the speaker output of the received sound in response to the squelch signal extracted by the extraction means, and muting of the mute means by the squelch signal. Sensitivity adjusting means (for example, squelch control unit 27) for adjusting sensitivity
And the like).

[0020] The sensitivity adjustment signal may arbitrarily adjust the magnitude of the squelch signal extracted by the extraction means.

[0021]

The operation of the present invention will be described with reference to the wireless device and the remote control device shown as realization examples in FIGS. Note that the implementation example is not limited to FIGS. 1 and 2.

When a radio wave is not received in the radio apparatus, both the voice output and the noise component output of the demodulator 13 are noise components only, the output of the noise amplifier 15 is the maximum output, and the tone signal of the tone signal generator 16 is After being converted by the squelch signal conversion unit 17, it is output as the maximum level. This tone signal passes through a squelch signal amplifying unit 18 and a signal synthesizing unit 19
Is combined with the audio signal output (in this case, noise) of the audio signal amplifier 14 and output to the line.

In the remote control device receiving this signal, the squelch signal passes through the squelch signal filter 25 and the squelch sensitivity adjustment unit 26, is input to the squelch control unit 27 as a maximum tone signal, and is output from the squelch control unit 27 to the audio signal mute unit. A control signal for mute is output to 22.
The audio signal mute unit 22 is turned off. As a result, the audio signal that has passed through the audio signal filter 20 and the audio signal amplifier 21 is cut off by the audio signal mute unit 22 and the output from the speaker 24 is cut off.

Next, when a radio wave is received, the noise output of the demodulation unit 13 fluctuates according to the strength of the received electric field, and the converted tone signal of the squelch signal conversion unit 17 controlled by the fluctuation also fluctuates. This signal passes through a squelch signal amplifying unit 18 and is combined with an audio signal by a signal combining unit 19 and sent out to a line. Therefore, when the received electric field is equal to or more than a certain level (in this case, the level at which the squelch opens), the noise output of the demodulation unit 13 decreases, and the squelch signal transmitted to the line also decreases to a level corresponding thereto.

In the remote control device that has received the signal with the reduced level, the squelch signal is
5. The signal is output to the audio signal mute unit 22 through the squelch sensitivity adjustment unit 26 and the squelch control unit 27. However, since the squelch signal level is reduced, the audio signal mute unit 22 that has been disconnected until then is connected. In this state, the squelch is opened, and the audio signal is output to the speaker 24 through the audio signal filter 20, the audio signal amplifier 21, the audio signal mute 22, and the power amplifier 23.

[0026]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a diagram illustrating a configuration example of a wireless device 1 in a wireless communication system that performs a squelch control method according to an embodiment of the present invention, and FIG. The configuration of the entire wireless communication system is the same as that shown in FIG.

First, the configuration of the wireless device 1 will be described with reference to FIG. In the wireless device 1, a transmitting unit and other parts are omitted because they are the same as known wireless devices, and FIG. 1 shows a receiving unit of the wireless device, and particularly a portion related to squelch control according to the present invention. Are mainly shown.
The wireless device 1 performs wireless communication with a wireless station such as a mobile device by an FM (frequency modulation) method.
_A wireless line is formed between _{1 to} 2 _n and the wireless station.

10 1 is an antenna, 102 is a high-frequency amplifier,
A receiving circuit including a local oscillator, an intermediate frequency amplifier, etc., 103
Is a demodulation circuit. The audio signal and the noise component are separated and output from the demodulation circuit 103. The audio signal is input to the audio signal amplification circuit 104, and the noise component is input to the noise amplification circuit 108 through the high-pass filter 107.

The output signal of the audio signal amplification circuit 104 is input to the signal synthesis circuit 116 through the power amplification circuit 105 and the audio signal level adjustment circuit 106.
At 16, the signal is combined with a squelch signal from a squelch signal level adjustment circuit 115 described later.

On the other hand, the output of the noise amplification circuit 108 passes through a noise rectification circuit 109 and a squelch signal control circuit 110 and is input to a squelch signal conversion circuit 113 as a control signal for squelch signal conversion. This squelch signal control circuit 11
A value of 0 adjusts the noise level to a level suitable for squelch signal conversion processing described later.

The tone signal generating circuit 111 is a circuit for generating a tone signal used as a squelch signal. The tone signal uses a high frequency in the transmission band of the transmission line 3 as a frequency. Tone signal level adjustment circuit 1
Reference numeral 12 denotes a circuit for adjusting the level of the tone signal generated by the tone signal generation circuit 111 to a size suitable for a squelch signal conversion process described later. Squelch signal conversion circuit 113
Is a circuit for converting the amplitude level of the tone signal input from the tone signal level adjustment circuit 112 into a level corresponding to the strength of the noise component from the squelch signal control circuit 110 and outputting the converted signal as a squelch signal. The squelch signal conversion circuit 113 can be composed of, for example, an electronic volume that uses a noise input as a control signal, an amplifier gain adjustment circuit that uses a noise input as a gain control signal, and the like. The squelch signal output from the squelch signal conversion circuit 113 is input to the signal synthesis circuit 116 through the squelch signal amplification circuit 114 and the squelch signal level adjustment circuit 115. The squelch signal level adjustment circuit 115 adjusts the level of the squelch signal to a level suitable for being synthesized with the audio signal by the signal synthesis circuit 116.

The synthesized output of the signal synthesizing circuit 116 is
Input to the line distributor 118 through the bell adjusting circuit 117
Is done. This line distributor 118 requires a composite output signal
To the number of transmission lines (usually corresponding to the number of remote controllers)
And each transmission line 3 ₁~ 3_nTo send to. this
Transmission line 3₁~ 3_nIs a wired line, a micro carrier circuit
Line, optical carrier line, cable carrier line, etc.
Line 3₁~ 3_nIs the remote control 2₁~ 2_nContact each
Has been continued. As a result, noise from the demodulation circuit 103
The tone signal converted to the level corresponding to the output is
Transmission line 3₁~ 3_nRemote control connected by
Device 2₁~ 2_nWill be sent to
You.

FIG. 4 shows a configuration example of the remote control device 2 side, and shows a squelch signal receiving portion according to the present invention. Other parts related to transmission and reception are omitted because they are the same as those of the known remote control device. The received signal received from the transmission line 3 is input to the signal amplification circuit 201,
Output from the low-pass filter 202 and the high-pass filter 207
Is input to

The low-pass filter 202 blocks a high-frequency tone signal for squelch control and passes an audio signal.
The output signal is amplified to a required level by the audio signal amplification circuit 203 and input to the audio signal mute circuit 204. The audio signal mute circuit 204 has a function of an analog switch that mutes an input signal in response to a control signal (DC level) from the squelch control circuit 212 and cuts off the output of the speaker 1. The output of the audio signal mute circuit 204 is amplified by the power amplification circuit 205 and then output to the speaker 206.

On the other hand, the high-pass filter 207 blocks a low-frequency audio signal and passes a high-frequency component including a squelch signal (a squelch control tone signal). Is done. The squelch signal identification circuit 208 is composed of a band-pass filter that passes only the frequency component of the squelch signal, and identifies and extracts only the squelch signal from the high frequency components.
The extracted squelch signal is applied to a squelch sensitivity adjustment circuit 209.
Is input to In this squelch sensitivity adjustment circuit 209,
The user can adjust the sensitivity of the input squelch signal to an appropriate level by using a squelch volume or the like. The squelch signal output from the squelch sensitivity adjustment circuit 209 is input to the squelch control circuit 212 through the squelch signal amplification circuit 210 and the squelch signal rectification circuit 211. The squelch control circuit generates a DC level control signal for controlling "disconnection / connection" of the audio signal mute circuit 208 according to the level of the input squelch signal, and generates the audio signal mute circuit 20.
4 is output.

The operation of this embodiment will be described below.
First, an operation example on the wireless device side in FIG. 3 will be described. Antenna 1
The FM wave received at 01 is converted to an IF frequency by a receiving circuit 102, and is separated into an audio signal and a noise component by a demodulation circuit 103 and demodulated. The audio signal is an audio signal amplifier circuit 10
4. After being input to the audio signal level adjustment circuit 106 via the power amplification circuit 105 and adjusted in level, the signal is input to the signal synthesis circuit 116.

On the other hand, the noise component output from the demodulation circuit 103 is passed by a high-pass filter 107, and the high-frequency component is amplified by a noise amplifier 108 and rectified by a noise rectifier 109. The signal is input to the squelch signal control circuit 110, and the squelch signal control circuit 110 outputs a control signal for controlling the squelch signal conversion circuit 113.

The tone signal for squelch control to be transmitted to the transmission line is generated by a tone signal generating circuit 111, adjusted and converted to an appropriate level and impedance by a tone signal level adjusting circuit 112, and converted to a squelch signal converting circuit 11.
3 is input. Since the squelch signal conversion circuit 113 is controlled by the control signal from the squelch signal control circuit 110, the tone signal input from the tone signal level adjustment circuit 112 has an amplitude level corresponding to the level of the noise component. The signal is converted and input as a squelch signal to a squelch signal amplifier circuit 114. The output is adjusted to an appropriate level and impedance by a squelch signal level adjustment circuit 115 and input to a signal synthesis circuit 116.

In the signal synthesizing circuit 116, the squelch signal is synthesized with the audio signal from the audio signal level adjusting circuit 106. The combined output is output level adjustment circuit 117
In after being level adjustment, and distributes the number of lines required by the line distributor 118, it is sent to the remote control device 2 ₁ to 2 _n connected to the transmission line 3 ₁ to 3 _n.

Next, an example of the operation of the remote control device 2 shown in FIG. 4 will be described. The signal transmitted to the transmission line on the side of the wireless device 1 is received by the remote control device 2 connected to the transmission line, passes through the signal amplification circuit 201, and the audio signal is transmitted to the low-pass filter 20.
2. The power amplification circuit 205 passes through the audio signal amplification circuit 203 and further passes through the squelch audio signal mute circuit 204.
, And then input to the speaker 206. The low-pass filter 202 passes only the frequency component of the audio signal and removes the tone signal to prevent the squelch signal from being heard from the speaker.

On the other hand, the high-frequency component including the squelch signal in the received signal passes through the high-pass filter 207, and only the squelch signal is selected and identified by the squelch signal identification circuit 208, and is input to the squelch sensitivity adjustment circuit 209. The squelch sensitivity adjustment circuit 209 adjusts the squelch sensitivity to an appropriate value. The output of the squelch sensitivity adjustment circuit 209 passes through the squelch signal amplification circuit 210 and the squelch signal rectification circuit 211 and is input to the squelch control circuit 212. The squelch control circuit 212 generates a control signal instructing “disconnection” when the magnitude of the input squelch signal exceeds a predetermined threshold, and
Output to If the threshold is not exceeded, no control signal is generated.

According to the above operation, when there is no reception signal from the mobile device or the like in the wireless device 1 or when there is a weak electric field, the output of the squelch signal control circuit 110 increases and the squelch signal conversion circuit 113 converts the output. The tone signal (that is, the squelch signal) is also increased and transmitted to the transmission line 3. As a result, the output of the squelch signal identification circuit 208 of the remote control device 2 that has received the signal becomes large,
A control signal is output from the squelch control circuit 212, the audio signal mute circuit 204 is turned off, and the speaker 20
The output from 6 disappears, and the squelch is operating.

Next, considering a case where a reception signal of a certain reception electric field level or more is input from the antenna 101 to the radio apparatus 1, the output of the squelch signal control circuit 110 becomes small, and the conversion of the squelch signal conversion circuit 113 is performed. The resulting tone signal (squelch signal) is also transmitted to the transmission line 3 in a reduced size. The output of the squelch signal identification circuit 208 of the remote control device 2 receiving this signal becomes small, and the squelch control circuit 2
12, the audio signal mute circuit 204 is in the “contact” state, the squelch opens, the audio signal passes, and after passing through the power amplifier circuit 205, the speaker 2
06 is output.

In this embodiment, each remote control device 2 can adjust the squelch sensitivity to a desired one by the squelch sensitivity adjustment circuit 209. Therefore, when there is a communication of a weak reception electric field with a large noise, if the communication is not addressed to the own station, the sensitivity can be adjusted so that the squelch sensitivity becomes high, so that the squelch function can be easily operated, thereby causing annoying sound. It is possible to cut off the output of noise. on the other hand,
A remote control device whose weak reception electric field is addressed to its own station can reduce the squelch sensitivity to make the squelch function difficult to work, so that only the remote control device can continue the call. It is possible to prevent a call from being interrupted simply because of a weak electric field.

In practicing the present invention, various modifications are possible. For example, in the above-described embodiment, an example is shown in which a high frequency component in the transmission band of the line is used as the tone signal frequency for squelch control. However, the present invention is not limited to this. For example, a low frequency in the transmission band of the line may be used. This low frequency is preferably set to a frequency (for example, several tens of hertz) lower than the voice communication band so as not to affect the voice communication. In this case, the remote control device uses a high-pass filter that passes more than the audio signal band in place of the low-pass filter 202 in the above-described embodiment, and uses a low-pass filter below the audio signal band instead of the high-pass filter 207. Configure to use

Further, the squelch signal is not limited to the one in which the amplitude level of the tone signal changes according to the strength of the noise component as in the above embodiment. For example, a multi-frequency signal used in a PB telephone or the like may be used as the squelch signal, the magnitude of the noise component may be quantized into a plurality of levels, and each level may be indicated by the multi-frequency signal.

In the above-described embodiment, the audio signal mute circuit 204 of the remote control device is a binary control for cutting off or connecting the passage of the audio signal. However, the present invention is not limited to this. A configuration may be adopted in which the level of the audio signal passing therethrough is increased or decreased continuously or stepwise according to the magnitude of the squelch signal.

In the above-described embodiment, the squelch sensitivity adjustment circuit 2 adjusts the squelch signal sensitivity adjustment in the remote control device.
Although the squelch volume control is performed in step 09, the present invention is not limited to this. For example, the squelch control circuit 214 may be configured to adjust a threshold value for generating a control signal.

In the above-described embodiment, the squelch signal is combined with the audio signal and transmitted to the remote control device side. However, the present invention is not limited to this, and a squelch signal transmission control line may be provided and transmitted. .

[0050]

As described above, according to the present invention,
The squelch control and the squelch sensitivity adjustment can be performed independently and independently on the remote control device side without performing the squelch control in the wireless device. Therefore, in each remote control device, the optimum squelch sensitivity setting can be performed according to the state of the electric field from the communication partner station at that time without affecting other remote control devices. Communication becomes possible even when communication is not possible. Further, in a control system capable of controlling squelch on / off by a conventional remote control device, there is no problem that unpleasant sound is output due to noise output to another remote control device when squelch is released,
The squelch control by a remote control device having a great merit can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, showing a configuration example on the side of a wireless device.

FIG. 2 is a diagram for explaining the principle of the present invention, showing a configuration example on the remote control device side.

FIG. 3 is a diagram showing one embodiment of a wireless device according to the present invention.

FIG. 4 is a diagram showing one embodiment of a remote control device according to the present invention.

FIG. 5 is a diagram illustrating a basic configuration example of a wireless communication system to which the present invention is applied.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 wireless device 2 _{1 to} 2 _n remote control device 3 _{1 to} 3 _n transmission line 11 antenna 12 reception unit 13 demodulation unit 14 audio signal amplification unit 15 noise amplification unit 16 tone signal generation unit 17 squelch signal conversion unit 18 squelch signal amplification unit Reference Signs List 19 signal synthesis unit 10 line distribution device 20 audio signal filter 21 audio signal amplification unit 22 audio signal mute unit 23 power amplification unit 24 speaker 25 squelch signal filter 26 squelch sensitivity adjustment unit 27 squelch control unit 101 antenna 102 reception circuit 103 demodulation circuit 104 Audio signal amplification circuit 105 Power amplification circuit 106 Audio signal level adjustment circuit 107 High pass filter 108 Noise amplification circuit 109 Noise rectification circuit 110 Squelch signal control circuit 11L Tone signal generation circuit 112 Tone signal level adjustment circuit 113 Squelch signal conversion circuit Reference Signs List 14 squelch signal amplifier circuit 115 squelch signal level adjustment circuit 116 signal synthesis circuit 117 transmission level adjustment circuit 118 line distribution device 201 signal amplification circuit 202 low-pass filter 203 audio signal amplification circuit 204 audio signal mute circuit 205 power amplification circuit 206 speaker 207 high Bandpass filter 208 Squelch signal identification circuit 209 Squelch sensitivity adjustment circuit 210 Squelch signal amplification circuit 211 Squelch signal rectification circuit 212 Squelch control circuit

Claims (7)

[Claims] In a wireless communication system comprising a wireless device and one or more remote control devices connected to the wireless device through a transmission line for remotely controlling the wireless device, the wireless device side receives a received radio wave. A squelch signal corresponding to the strength of the squelch control noise component is generated and transmitted to the remote control device through a transmission line, and the remote control device controls the communication output based on the received squelch signal to control each remote control. A squelch control method for a wireless communication system, wherein squelch control is performed for each control device. 2. The squelch signal according to claim 1, wherein a tone signal in a transmittable band of a transmission line between the wireless device and the remote control device has its intensity changed according to the intensity of a squelch control noise component of a received radio wave. The squelch control method for a wireless communication system according to claim 1, wherein 3. A squelch signal generating means for generating a squelch signal corresponding to the strength of a squelch control noise component of a received radio wave, and transmitting the squelch signal generated by said squelch signal generating means to a remote control device via a transmission line. A wireless device comprising: 4. A squelch signal generating means for detecting a strength of a squelch control noise component of a received radio wave, and generating a tone signal within a transmittable band of a transmission line between a radio device and a remote control device. 4. A squelch signal converting means according to claim 3, further comprising: a tone signal generating means for generating a squelch signal by changing the strength of said tone signal in accordance with the strength of a squelch control noise component detected by said detecting means. Wireless device. 5. A signal synthesizing means for synthesizing a squelch signal and a received voice signal to simultaneously transmit a squelch signal and a received voice signal over one transmission line to one remote control device. A wireless device as described. 6. Extraction means for extracting a squelch signal from a signal received from a wireless device, mute means for muting a speaker output of a received voice in response to the squelch signal extracted by the extraction means, And a sensitivity adjusting means for adjusting the muting sensitivity of said mute means. 7. The remote control device according to claim 6, wherein said sensitivity adjustment signal arbitrarily adjusts the magnitude of the squelch signal extracted by said extraction means.