JPH04175017A - Squelch device for portable radio equipment - Google Patents

Abstract

PURPOSE:To vary a discrimination level representing the presence of a radio wave continuously and to monitor a voice and noise at no input by varying the discrimination level representing the presence of a received radio wave continuously and turning off the squelch function with switch-off. CONSTITUTION:Each output of a noise squelch detection circuit 3, a tone squelch detection circuit 5 and a squelch switched variable resistor is referred respectively to as A, B, C. With a switch 2a turned on, when its output C is at an L level, an output D of a logic circuit 6, that is, a mute signal is at an H regardless of the outputs A, B and sound is outputted from a speaker. The discrimination level of the presence of a received radio wave is changed by a variable resistor 2b of a volume control 2 and the switch 2a is turned off to turn off the squelch function. Thus, the discrimination level of the presence of a received radio wave is varied continuously and the sound of the reception signal with a different tone frequency and noise at no input are monitored.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a squelch device for a portable radio used for commercial radio in the VHF band and UHF band.

BACKGROUND OF THE INVENTION Conventionally, there have been two squelch methods for portable wireless devices used in business communication lines: a method using only a noise squelch, and a method using a combination of a noise squelch and a tone squelch.

Noise squelch uses the fact that noise in frequency components higher than the voice band and lower than the intermediate frequency decreases as the receiving input electric field increases.
This method detects the presence or absence of received radio waves using a discriminator (called a discriminator).

In the case of a squelch method using only a noise squelch, there are two methods: a method in which the received electric field strength to be detected is fixed and a method in which it is semi-fixed.

Of these, in the case of the former method of fixing the received field strength to be detected, the noise component of the discriminator output of the receiver changes depending on environmental conditions such as ambient temperature, so the setting of the determination level for the presence or absence of received radio waves is It will be deeper.

This is because if the level setting is not set deeply, problems such as the squelch remaining open due to changes in environmental conditions will occur.

However, if the determination level for the presence or absence of received radio waves is set to a deep level, the service area in which line communication can be performed becomes narrower.

Therefore, in order to widen the service area of chain line communication as much as possible, there is a method of semi-fixing the determination level of the presence or absence of received radio waves. In this case, in conjunction with a squelch volume attached to the radio, the level for determining the presence or absence of received radio waves can be changed.

Generally, in the above-mentioned commercial fin lines, the same frequency is often shared by different users, and in this case, in order to avoid interference and improve business efficiency, a method is used in which noise squelch and tone squelch are used in combination.

Problems to be Solved by the Invention However, in the case of the above-mentioned conventional squelch method that uses a combination of noise squelch and tone squelch, when received waves of the same frequency but different tone frequencies are received, the above-mentioned squelch volume is used to determine whether there is a received radio wave or not. Even if the determination level setting was changed, it was not possible to monitor the voice of the received signal and the noise during unmanned operation.

The present invention solves such conventional problems, and when squelching is performed using a combination of noise squelch and tone squelch, it is possible to monitor the sound of received signals with different tone frequencies, and to reduce noise when unmanned. It is an object of the present invention to provide an excellent squelch device for a portable wireless device that enables monitoring.

Means for Solving the Problems In order to achieve the above object, the present invention provides a tone squelch circuit that has a switch circuit that switches according to the level of a DC voltage obtained by detecting an audio frequency component out of the output from a discriminator. a detector circuit for the squelch, a variable resistor for changing the setting of the determination level of the presence or absence of received radio waves from the output of the discriminator, and a switch for turning off the squelch function when the squelch function is turned off; A noise squelch detection circuit having a switch circuit that switches according to the level of a DC voltage obtained by rectifying the noise component of the output of the discriminator that has passed through the variable resistor of the switch-equipped volume; A configuration comprising a detection circuit and a logic circuit that manually inputs each output of the tone squelch detection circuit and the switch of the squelch switch-equipped volume and turns off the squelch function when the squelch switch-equipped volume switch is turned off. did.

Therefore, according to the present invention, the level of the electric field for determining the presence or absence of radio waves can be continuously varied by making it possible to continuously change the level for determining the presence or absence of received radio waves, and turning off the squelch function by turning off the switch. In addition, it has the effect that it is possible to monitor the sound of received signals having different tone frequencies and to monitor the noise during unmanned operation.

Example FIG. 1 shows the configuration of an embodiment of the present invention.

In FIG. 1, numeral 1 denotes a noise amplifier and band pass filter C for noise squelch (hereinafter referred to as BPF), and hereinafter referred to as noise amplifier BPF. The output of a discriminator of a receiver (not shown) is input to the input terminal of the noise amplifier BPF 1.

Further, 2 is a volume with a squelch switch, which has a switch 2a and a variable resistor 2b, and is provided on the panel part of the radio, and the variable resistor 2b is connected between the output terminal of the noise amplifier BPFI and the ground. , variable resistor 2b
One end of the ground side is connected to the logic circuit 6 via the switch 2a.
connected to the input end of the

3 is a volume 2 with a squelch switch at its input end.
The noise amplifier B is connected to the movable terminal of the variable resistor 2b, and its output terminal is connected to the input terminal of the logic circuit 6.
This is a noise squelch detection circuit composed of a PFI output detection circuit and a switch circuit.

On the other hand, reference numeral 4 indicates a tone squelch BPF and an amplifier (hereinafter referred to as tone squelch B
5 is the BP for this tone squelch.
This is a tone squelch detection circuit that receives the output of the F amplifier 4 and performs detection and switching operations.

The logic circuit 6 includes a volume 2 with a squelch switch.
Output 01 of the movable terminal of the switch 2a, output A5 of the noise squelch detection circuit 3, and tone squelch detection circuit 5
This is a logic circuit which receives the output B of and performs logical processing using these inputs A to C to determine the mute condition and obtain the output.

FIG. 2(a) is a plan view showing the symbols of the volume 2 with the squelch switch as seen from the panel.
AXJ, rOFFJ, etc. are displayed to indicate the position of the movable terminal of the variable resistor 2b depending on the amount of rotation of the knob 2C, and also the setting change value of the determination level for the presence or absence of received radio waves.

Further, FIG. 2(b) is a circuit diagram showing circuit symbols of this volume 2 with a squelch switch, and the same parts as in FIG.

Next, the operation of the above embodiment will be explained. In the above embodiment, the output of the discriminator is the noise amplifier B
It is input to the PFI, where the noise components other than the audio frequency are extracted by the BPF, amplified by the amplifier, and then input to the noise squelch detection circuit 3 through the variable resistor 2b of the volume 2 with the squelch switch, where the noise component is extracted by the BPF and amplified by the amplifier. The component is rectified to become a DC component, which is switched to rHJ level or rLJ level by a switch circuit depending on the DC component, and output A is output to logic circuit 6.

Further, the output of the discriminator is input to a tone squelch BPF amplifier 4, where frequency components in the audio band are extracted by the BPF and amplified by the amplifier, and then sent to a tone squelch detection circuit 5.

The tone squelch detection circuit 5 rectifies the audio component into a DC component, which is switched between the rHJ level and the rLJ level by a switch circuit according to the level of the DC component, and an output B is output to the logic circuit 6.

Also, switch 2 of volume 2 with squelch switch
a outputs an output C to the logic circuit 6 at the ground level, that is, rLJ level when it is on, and at rHJ level when it is off.

As mentioned above, when the outputs of the noise squelch detection circuit 3, the tone squelch detection circuit 5, and the switch 2a of the squelch switch-equipped volume 2 are respectively A, B, and C, the truth value of the logic circuit 6 is As shown in Figure 3.

That is, the switch 2a is turned on, and the output C of the switch 2a is output when C=“L”.

Regardless of the value of B, the output D5 of the logic circuit 6, that is, the mute becomes rHJ, and audio is output from a speaker (not shown).

As described above, according to the above embodiment, the squelch function is turned off by changing the determination level of the presence or absence of received radio waves by the variable resistor 2b of the volume 2 with the squelch switch, and by turning off the switch 2a. This has the effect of being able to continuously vary the determination level of the presence or absence of radio waves, and also being able to monitor the sound of received signals with different tone frequencies and the bran sound when unmanned.

Effects of the Invention As described above, the present invention provides a tone squelch detection circuit having a switch circuit that switches according to the level of the DC voltage obtained by detecting the audio frequency component of the output from the discriminator, and the above-mentioned discriminator. A volume with a squelch switch has a variable resistor that changes the level setting for determining the presence or absence of received radio waves from the output of the generator, and a switch that turns off the squelch function when the squelch function is turned off, and the variable resistor of the volume with the squelch switch a noise squelch detection circuit having a switch circuit that switches according to the level of a DC voltage obtained by rectifying the noise component of the output of the discriminator after passing through the noise squelch; this noise squelch detection circuit and the tone squelch detection circuit; and a logic circuit which inputs the respective outputs of the switch of the volume with the upper epsilon squelch switch and turns off the squelch function when the switch of the volume with the squelch switch is turned off.

Therefore, by making it possible to continuously change the level for determining the presence or absence of received radio waves, and turning off the squelch function by turning off the switch, it is possible to continuously vary the electric field level for determining the presence or absence of radio waves, and also to adjust the tone frequency. This has the effect that it is possible to monitor the voices of different received signals and to monitor the noise during unmanned operation.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a squelch device for a portable radio according to an embodiment of the present invention, and FIG. front view showing the symbol,
FIG. 2(b) is a circuit diagram showing a circuit symbol of the volume with a squelch switch, and FIG. 3 is an explanatory diagram for explaining the truth value of the logic circuit of the squelch device of the portable radio. 2...Volume with squelch switch, 2a...
Switch, 2b... Variable resistor, 3... Detection circuit for noise squelch, 5... Detection circuit for tone squelch, 6
...Logic circuit. Name of agent Patent attorney Akira Koeji and two others Figure 1 2 Volume 2JL with squelch switch...
For switch...Variable resistor 3...Detection circuit for nozzle squelch 5...Detection circuit for tone squelch and switch circuit

Claims (1)

[Claims] A tone squelch detection circuit having a switch circuit that switches according to the level of a DC voltage obtained by detecting an audio frequency component out of the output from the discriminator; A volume with a squelch switch, which has a variable resistor that changes the setting of the judgment level for the presence or absence of received radio waves, and a switch that turns off the squelch function when it is off, and a disc limiter that passes through the variable resistor of the volume with the squelch switch a noise squelch detection circuit having a switch circuit that switches according to the level of a DC voltage obtained by rectifying the noise component of the output of the noise squelch, the noise squelch detection circuit, the tone squelch detection circuit, and the squelch detection circuit. A squelch device for a portable radio device, comprising a logic circuit that inputs each output from a switch of a volume with a switch and turns off a squelch function when the switch of the volume with a squelch switch is turned off.