JPH06284025A - Tone squelch type receiver - Google Patents

Abstract

PURPOSE:To obtain a tone squelch type receiver which can properly adjust reproduced sound volume when powered ON as to a tone squelch type receiver which occupies a radio communication over a common channel by utilizing the code of the frequency of a tone superimposed on a communication signal. CONSTITUTION:This receiver is provided with an actuation informing means 16 which detects the receiver being powered ON, resets a tone squelch for a certain period of time, and secures the connection between an amplifying means 12, and an output means 13 in a disconnecting means 14 unconditionally. An operator while hearing a speech output based upon the output signal of a receiving means 11 can adjust the amplification degree of the amplifying means 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tone squelch type receiver that occupies a common channel wireless communication by utilizing the frequency matching of tones superimposed on a communication signal.

[0002]

2. Description of the Related Art Wireless communication using tone squelch is
The radio frequency of the common channel is occupied by using the code of the frequency of the tone superimposed on the communication signal. The tone squelch transmitting side transmits a radio signal in a form in which a ringing signal of a constant frequency is superimposed on the voice, and at the receiving side, only when the frequency of the ringing signal matches the natural frequency previously assigned to the receiving side, Allow audio output. Therefore, the tone squelch function can perform a plurality of independent wireless communications using the radio frequency band of one channel under the condition that the wireless communications are performed at different times.

FIG. 4 is an explanatory diagram of the tone squelch function. Here, by utilizing the radio frequency band of one channel, a large number of mobile stations can communicate independently with respect to one transmitting station at different times.

In FIG. 4, the mobile stations 41 to 46 have 1
Different ringing frequencies (tone frequencies) in the 50 to 170 Hz band are assigned. For example, 1 for mobile station 44
60 Hz is allocated.

The mobile station 44 receives the radio wave signal transmitted from the transmission station 40, reproduces the voice signal, and identifies the calling frequency superimposed on the voice signal. Then, the mute state is released and the voice output is executed only when the calling frequency is 160 Hz, and the mute state is maintained and the voice output is not executed when the calling frequency is different from 160 Hz.

That is, the call signal transmitted from the transmitting station 40 has a key (or secret number) called a calling frequency, and the mobile station 41 whose key matches the keyhole called an assigned frequency.
Only in one of ~ 46 can the final audio output be reached.

Therefore, the transmitting station can arbitrarily select one of the mobile stations 41 to 46 by selecting a specific ringing frequency, and the mobile station 4 can be used by stacking a plurality of ringing frequencies.
Any combination of 1 to 46 can be selected. On the other hand, if the calling station 40 is assigned a specific calling frequency different from these, the mobile stations 41 to 46 side superimpose the signal of this calling frequency on the transmission signal, so that the calling from the mobile stations 41 to 46 side. Independent communication can be secured for the station 40.

For example, the transmitting station 40 which selects the mobile station 44
Is a sine wave with a ringing frequency of 160Hz superimposed on the audio signal and F
It is M-modulated, converted into a high frequency of the allocated radio frequency band of one channel, and output as a radio wave into the air through the rooftop antenna.

On the other hand, in the mobile station 44, the high frequency signal received through the antenna is converted into an intermediate frequency to extract the band of one channel, and the original voice signal containing the calling frequency component is extracted through FM demodulation.

Then, the calling frequency extraction unit 4 of the mobile station 44
In 4A, the calling frequency component is extracted from the original voice signal and the frequency is measured, and in the identifying unit 44B, the matching between the frequency of 160 Hz set in the setting unit 44C and the frequency of the calling frequency component is identified. Therefore, the switch 44E is connected to cancel the tone squelch, and the speaker is operated by using the amplified signal of the voice + calling frequency component.
Play a call from.

The calling frequency component included in the voice-reproduced call is a noise component that is irrelevant to the actual communication content, but the reproduced sound pressure is limited by the input-output characteristics of the speaker. Suppressed to a barely noticeable level.

At this time, the other mobile stations 41, 42, 43,
Similarly, in 45 and 46, the call signal is reproduced from the radio frequency band of 1 channel, but since the calling frequency does not match the assigned frequency, the mute state by tone squelch continues and the interruption of the input to the speaker is maintained. I cannot hear the call from the originating station 40 at all.

[0013]

In the communication system in which the central transmitting station 40 and a large number of mobile stations 44 are combined as shown in FIG. 4, the individual mobile stations 41 to 46 turn on / off the power supply.
Tend to be carried out relatively often. Then, when the mobile stations 41 to 46 are powered on, there is a problem that the volume adjustment for reproduction cannot be properly executed.

That is, in the mobile stations 41 to 46, since the power of the wireless communication device is turned on, the mobile station 41 to 46 shifts to the mute state by tone squelch. Therefore, unless wireless communication in which the calling frequencies are coincidentally received is received, a speaker is used. I can't control the volume because I can't get any playback sound.

For example, there are cases where a central base station performs a vehicle dispatch command and operation management for a large number of taxi mobile stations dispersed in a city through wireless communication. At this time, in each taxi, the entire power supply system of one taxi is turned off after each waiting time, driver's break, and meal time, and then turned on again. Then, when leaving the vehicle by turning off the entire power supply system of one taxi, the driver may erroneously operate the volume control of the wireless communication device.

When the driver gets on the vehicle for the first time, the wireless communication device is activated in the volume adjustment state of the previous day or in an unknown volume adjustment state of another driver. Therefore, it may be inconvenient if the volume control is left as it is.

That is, if the volume adjustment is excessive, and if the reproduction of a large volume is suddenly started when the calling frequencies of the wireless communication from the base stations match, the driver may be surprised and make a mistake in driving. There is. Further, in the case of a taxi, a sudden call may surprise passengers and cause discomfort, which is not preferable in business.

On the other hand, if the volume control is too low, there is a possibility that the call frequency of the wireless communication from the base station will match and miss the call reproduced by the speaker. In addition, if the volume is rushed to increase the volume after the call is started, the operation or adjustment of the wireless communication device may be erroneous, and it is dangerous because the driver is distracted from the driving.

Further, in the daytime and urban areas where the noise level is high, it is necessary to increase the volume of the call reproduction as compared with the early morning and forest areas where the noise level is low. In this sense, the volume control of the wireless communication device is indispensable. . However, it is still difficult to adjust the volume when no sound is output from the speaker.

Further, in the case of a taxi, in addition to the wireless communication device, a large number of electric devices such as a navigation device, a receipt issuing device, a radar device and a television may be attached. In such a case, if it is obliged to turn on all the electric devices one by one each time the engine is started and the electric system of the vehicle is started, there is a possibility that the power of the essential wireless communication device may be forgotten to be turned on. Increase. Then, there is a case where the work of the day is finished as it is without forgetting to turn on the power of the wireless communication device.

In other words, when the driver gets into the vehicle and starts (restarts) the business, without increasing the burden on the driver,
It is desirable that the power-on of the wireless communication device and the volume adjustment state of call reproduction are confirmed, and at the same time, if the volume adjustment is inappropriate, the driver is obliged to immediately make a readjustment.

An object of the present invention is to provide a tone squelch type receiver capable of properly adjusting the reproduction volume when the power is turned on.

[0023]

FIG. 1 is an explanatory diagram of the basic configuration of the present invention. In FIG. 1, a tone squelch type receiver according to claim 1 includes a receiving means 11 for reproducing an original communication signal from a received radio wave, and an amplifying means 12 for amplifying the communication signal with an adjustable amplification degree. Output means 13 for forming a voice output by using the communication signal amplified by the amplification degree, and interruption means 14 capable of interrupting the input to the output means 13 with respect to the amplified communication signal.
And a ringing signal having a constant frequency included in the communication signal is extracted, and when the frequency of the ringing signal matches a pre-assigned natural frequency, the ringing means 14 executes the connection of the input. Signal identification means 1
In the tone squelch-type receiver having 5 and 5, the start notification means 16 that detects that the power of the receiver is turned on and unconditionally secures the connection of the input in the cutoff means 14 for a certain time. It is provided.

A tone squelch type receiver according to a second aspect is the tone squelch type receiver according to the first aspect, wherein signal generating means for forming a reference voice signal corresponding to an output level of the receiving means at the time of receiving a radio wave, Switching means capable of switching the input to the amplifying means from the receiving means to the signal generating means, and detecting that the power of the receiver is turned on, the signal generation of the switching in the switching means for a predetermined time. The start notification means defined on the means side is added.

[0025]

In FIG. 1, in the tone squelch type receiver according to claim 1, one or more frequencies for performing tone squelch are assigned, and the frequency of the calling signal included in the communication signal demodulated and reproduced from the received radio wave is When the frequency matches the assigned frequency, the tone squelch is released and the output means 13 is allowed to use the communication signal.

The receiving means 11 preferably receives a radio wave containing a frequency-modulated (FM-modulated) call signal and reproduces the call signal. However, the receiving means 11 is
It may be one that receives a radio wave including a communication signal of another modulation method such as phase modulation. The amplification unit 12 amplifies the call signal, and the output unit 13 converts the amplified call signal into a voice output and reproduces the voice.

The tone squelch type receiver can form a two-way radio telephone device by being combined with a transmitter that forms an outgoing radio wave of the same channel by using the same modulation standard as the received radio wave.

Call signal identifying means 15 and blocking means 14
Is a tone squelch, identifies the communication signal received and reproduced by the receiving means 11, and brings the cutoff means 14 into a contact state when the frequency of the ringing signal included in the communication signal matches the frequency assigned by the receiver. Transfer to cancel tone squelch.

The activation notifying means 16 forcibly cancels the tone squelch for a predetermined time immediately after the power of the receiver is turned on, and whether the calling signal is matched or not matched and the communication signal of the same channel is not present at all. Irrespectively, the audio reproduction in the output means 13 is executed.

Therefore, for a predetermined period of time immediately after the power of the receiver is turned on, not only the call with which the call signal matches and the call with which the call signal does not match, but also other radio wave information and noise signals included in the band of the same channel, The voice is reproduced through the output means 13 and the operator who turned on the power is notified.

When the operator hears this voice and feels that the power of the receiver has been turned on and feels that the volume adjustment is not appropriate, the operator operates the amplifying means 12 to adjust the amplification degree by the end of the predetermined time. To do.

After that, when a predetermined time elapses, the forced tone squelch release by the activation notifying means 16 ends,
The normal tone squelch state by the calling signal identifying means 15 and the blocking means 14 is entered.

By the way, the tone frequency used for tone squelch can be selected as an arbitrary value in a voice frequency band that can be modulated. The tone frequency should be selected from a frequency outside the audible range where it is not noticeable as noise when the sound is reproduced, but (1) cut off by the input-output characteristics of the output means 13 and the amplification means 12, (2) suitable A frequency in the audible range may be used by using a technique such as removal from a communication signal using a bandpass filter.

Further, in the calling signal identifying means 15,
When an analog resonant circuit is used to identify the tone frequency, the tone frequency interval selected from the constraint of the Q value of the resonant circuit cannot be made very narrow, but a digital frequency counter combining a timer and a pulse counter is used. In the case of using, a large number of tone frequencies can be set at intervals as small as several Hz, and a single radio frequency channel can be used to secure a large number of independent communications.

Further, when the receiving means 11 cannot acquire the communication signal of the same channel when the power is turned on, the amplification degree of the amplifying means 12 may be adjusted while listening to the output noise of the output means 13, but proper communication is possible. It is difficult to determine whether or not the volume level when the signal is obtained is actually proper.

Therefore, (1) by temporarily bypassing the bandpass filter in the receiving means 11 or the like, noise outside the channel band and broadcast radio waves are also taken in, and a noise signal is positively formed. (2) Call Even during the period when it is not performed, a music program or the like that does not include a calling signal may be left on the same channel from the sending side.

Further, in the above description, the communication signal is an analog call signal and the output means 13 is a voice reproducing device such as a speaker or earphone. However, the communication signal may be a video analog signal, digital data, etc. Means 1
The device 3 may use a communication signal in another output form other than voice, such as a video device or a data processing device.

In this case, the amplifying means 12 does not necessarily have to have an adjustable amplification degree, and the tone squelch type receiver as a whole can be understood as a radio wave information selection device using tone squelch except for a radio telephone.

Further, as a configuration that can achieve the same effect without using the shutoff unit 14, there is a configuration in which the amplification unit 12 that changes the amplification degree according to the output of the activation notification unit 16 is provided. At this time, the blocking means 14 is short-circuited, and when the frequency of the calling signal matches the pre-assigned natural frequency, the amplification degree is expanded to allow the operator to hear clearly, but on the other hand, they do not match. In this case, the degree of amplification is reduced to make the communication content inaudible.

In the tone squelch type receiver of claim 2,
The tone squelch type receiver is exposed to the reproduced sound through the output means for a predetermined time immediately after the power is turned on to provide the operator with an opportunity to adjust the amplification means, but relying on the reception means as the signal source of the output means. Instead, the reference audio signal by the built-in signal generating means is used.

This does not mean that an appropriate communication signal is received when the power is turned on, and that the volume level at which other radio wave information and noise signals included in the band of the same channel are reproduced is
This is because they do not necessarily match the volume level when the essential communication signal with which the calling signal matches is reproduced.

In this respect, the reference voice signal corresponds to the reproduction output level of the communication signal in which the tone squelch matches, and the volume can be adjusted precisely. In addition, it is possible to select music, a lesson, etc., which is preferable from the viewpoint of hearing or business, without fear of violating the secret of communication protected by tone squelch.

When a frequency-modulated radio wave (FM wave) is received, the obtained noise level is originally low, and the reproduced voice level is almost constant regardless of the intensity of the received radio wave. By using the signal, it is possible to accurately estimate the reproduction output level of the communication signal having the matched tone squelch.

[0044]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is an explanatory diagram of the configuration of a wireless communication device of the first embodiment. Here, the power-on is detected by detecting the voltage of the power line.

In FIG. 2, the electric wave received through the antenna 21A is converted into an intermediate frequency signal by the receiving circuit 21B, and an AC signal of one channel width assigned to wireless communication is extracted through a bandpass filter. F
The M demodulation circuit 21C FM demodulates the AC signal to demodulate the original communication signal modulated on the sending side.

The communication signal demodulated by the FM demodulation circuit 21C includes a call signal for operating the tone squelch, which is superimposed on the call signal. The tone frequency measuring circuit 25A is
The call signal is separated from the communication signal and its frequency is measured. The frequency measurement result is input to the microcomputer 25C.

On the other hand, the communication signal including the call signal and the ringing signal is amplified by the audio amplifier circuit 22A, and the power can be increased to a level suitable for reproduction by the speaker 24A. The amplification degree in the audio amplifier circuit 22A can be arbitrarily set by the operator through the volume 22B. The communication signal amplified through the audio amplifier circuit 22A immediately drives the speaker 24 to output a sound when the analog switch 23 is contacted.

The power supply line of the receiver 20 is connected to the battery 27 when the operator turns on the power switch 25S. When the power switch 25S is turned on, the receiving circuit 21
B, FM demodulation circuit 21C, audio amplification circuit 22A,
The tone frequency measuring circuit is activated and the microcomputer 25C is activated.

The activated microcomputer 25C immediately executes the tone squelch program, but the detection circuit 25B
While the output of is maintained at H, the analog switch 23 is unconditionally connected. The detection circuit 25B maintains the output at H for 5 seconds after the operator turns on the power switch 25S, and then lowers the output to L. That is, the microcomputer 25
The substantial tone squelch program in C is started 5 seconds after the power switch 25S is turned on.

Therefore, for 5 seconds after the operator turns on the power switch 25S, regardless of the presence / absence of a ringing signal and whether the frequency of the ringing signal coincides with the assigned frequency,
A communication call using the radio frequency band of the same channel is reproduced as voice through the speaker 24. In addition, even when no communication call is performed, white noise due to noise radio waves can be heard.

The tone squelch frequency assigned to the receiving section 20 is written in the memory 25M in a non-volatile state. After 5 seconds have elapsed since the power switch 25S was turned on, the microcomputer 25C compares the assigned frequency called from the memory 25M with the frequency of the calling signal measured by the tone frequency measuring circuit 25A, and sets the difference between them. If it is within the range, the analog switch 23 is set to the connected state.

The wireless communication device of the first embodiment is provided with the transmitting unit 26 in addition to the receiving unit 20 as described above.
Two-way transmission can be performed. The transmitter 26 FM-modulates the voice message of the operator, converts it into a radio wave in the radio frequency band of the same channel, and sends it to the air.

Although the independent communication circuit 25B is provided in the wireless communication device of the first embodiment, the connection of the analog switch for 5 seconds after the power is turned on may be realized as a start program of the microcomputer 25C. For example, the analog switch 33
Is a normally closed element, and the voltage is applied to the analog switch 33 of the microcomputer 35C by turning on the power 5
Hold for only a second.

FIG. 3 is an explanatory diagram of the configuration of the wireless communication device of the second embodiment. Here, a reference sound generating circuit 36 and a changeover switch 37 are added to the receiving unit 20 of the first embodiment.

In FIG. 3, the radio wave received through the antenna 31A is input to the receiving circuit 31B and the AC signal of one channel width is extracted. FM demodulation circuit 31C
Performs FM demodulation of the AC signal to demodulate the communication signal. The tone frequency measuring circuit 35A separates the calling signal from the communication signal and measures its frequency.

On the other hand, the communication signal is the audio amplification circuit 3
If it is amplified by 2A and the analog switch 33 is in the connected state, the operator can hear the audio output through the speaker 24 at the volume level adjusted by the operator through the volume 32B.

The power line of the receiving section 30 is turned on by the operator turning on the power switch 35S. Microcomputer 3 started by turning on power switch 35S
5C immediately executes the tone squelch program, but the analog switch 33 is unconditionally connected for 5 seconds after the power switch 35S is turned on in which the output of the detection circuit 35B is kept at H, and the changeover switch 37 Is unconditionally connected to the reference sound generating circuit 36 side.

The detection circuit 25B waits for the start of the substantial tone squelch program in the microcomputer 35C for 5 seconds after the power switch 25S is turned on, during which the repeated melody line generated by the reference sound generation circuit 36 is output to the audio amplification circuit. Input to 32A. The audio amplifier circuit 32 allows the operator to hear the voice output of the melody line through the speaker 24 at the volume level that the operator has adjusted through the volume 32B.

Five seconds after the power switch 35S is turned on, the changeover switch 37 is switched to the FM demodulation circuit 31C side, and the analog switch 33 is turned off. Then, the microcomputer 35C compares the assigned frequency called from the memory 35M with the frequency of the calling signal measured by the tone frequency measuring circuit 35A, and if the difference between them is within the allowable range, the analog switch 33 is connected. To do.

[0060]

According to the tone squelch type receiver of claim 1, the mute state by the tone squelch is released only for a short time interval immediately after the power of the receiver is turned on, and the volume is adjusted by the amplifying means and output through the output means. Since the audio output is heard by the operator, the operator can surely recognize the power-on of the receiver, can judge whether the audio output level is appropriate, and if it is not appropriate, confirm with the actual playback sound to confirm that it is appropriate. Can be adjusted to the level.

Therefore, for example, when it is used for wireless communication with a base station and a large number of taxis, there is a concern that each taxi may miss the wireless communication from the base station due to forgetting to turn on the power of the wireless communication device or adjusting the volume too low. Disappears. Further, the excessive adjustment of the volume eliminates the fear of the driver being surprised or causing the passengers to feel uncomfortable.

Further, since the volume adjustment time is almost limited when the power is turned on, it is not necessary to provide a large knob or a layout of an easily accessible adjusting section for volume adjustment during operation. This increases the degree of freedom in the panel layout of the wireless communication device, and facilitates the downsizing of the device.

According to the tone squelch type receiver of the second aspect, even when the voice output of a sufficient level cannot be obtained through the radio wave, the reference voice signal generated by the signal generating means is used instead to output. The amplification degree of the amplification means can be adjusted to an appropriate level while checking the actual reproduced sound through the means.

Further, there is no fear that the release of the tone squelch will violate the secret of communication of another assigned frequency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a basic configuration of the present invention.

FIG. 2 is an explanatory diagram of a configuration of a wireless communication device according to the first embodiment.

FIG. 3 is an explanatory diagram of a configuration of a wireless communication device according to a second embodiment.

FIG. 4 is an explanatory diagram of a tone squelch function.

[Explanation of symbols]

 11 receiving means 12 amplifying means 13 output means 14 blocking means 15 call signal identifying means 16 activation notifying means

Claims (2)

[Claims] 1. A receiving means (11) for reproducing an original communication signal from a received radio wave, an amplifying means (12) for amplifying the communication signal with an adjustable amplification degree, and an amplification with the adjusted amplification degree. Output means (13) for forming an audio output using the amplified communication signal, and the output means (1) for the amplified communication signal.
3), which is capable of blocking an input to the input, and a call signal of a constant frequency included in the communication signal, and when the frequency of the call signal matches a pre-allocated natural frequency, A tone squelch type receiver having a ringing signal identifying means (15) for executing the connection of the input in the cutoff means (14), and detecting that the power of the receiver is turned on for a predetermined time. A tone squelch type receiver characterized in that a start notification means (16) for unconditionally securing the connection of the input in the cutoff means (14) is provided. 2. The tone squelch type receiver according to claim 1, wherein a signal generating means for forming a reference voice signal corresponding to an output level of the receiving means at the time of receiving a radio wave, and an input to the amplifying means for the receiving means. Switching means capable of switching from the signal generating means to the signal generating means, and an activation notifying means which detects that the power of the receiver is turned on and determines the switching in the switching means on the signal generating means side for a certain time. A tone squelch type receiver characterized by adding ,.