JPH0262061B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a squelch control method for a wireless communication device.

Conventional squelch methods for wireless communication devices, especially FM mobile communication devices, include a carrier squelch method that detects the presence or absence of a carrier, or a squelch method that detects the noise generated at the output end of the demodulator when a carrier is not present. The noise squelch method is common, and both methods do not have the ability to identify interference waves of the same wavelength received from other radios, and will output audio for communications other than the intended purpose, so prevent this. For this reason, a so-called tone squelch method was used in which a specific continuous tone signal was always superimposed on the transmitted wave, and the sound was output to the outside only when the receiver detected this signal.

However, in the conventional tone squelch method as described above, since the continuous tone signal is always mixed with the modulated signal and transmitted, a part of the limited frequency deviation, for example 0.5KHz out of 5KHz, must be allocated, which means that the information that can be transmitted must be allocated. The disadvantage was that the volume of calls was reduced and the quality of calls was deteriorated.

The present invention has been made to eliminate the drawbacks of the conventional tone squelch method as described above.
A squelch open signal with a predetermined pattern is transmitted during a short period when the transmitter is started up and a period when no modulation signal is present, and when the modulation signal continues for a certain period of time or more, the squelch open signal is transmitted as a transmission wave with a required period. The squelch is released for a predetermined time while the superimposed squelch open signal is detected by the receiver and after the detection signal disappears, and the squelch function of the receiver is controlled by the squelch open signal sequentially transmitted by the transmitter. The purpose of this invention is to provide a squelch control method that provides

The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 1 is a block diagram showing an embodiment of the squelch control method according to the present invention.

In this figure, 1 is the transmitter and 2 is the oscillator.
It is a general transmitter consisting of OSC, modulator MOD, high frequency part RFAMP, modulation pre-circuit IDC, and microphone M, and a part of the output of microphone M is sent through voice controller VOK to detect the presence or absence of it. It is connected to the mark timer circuit M/TIM, and its output controls the squelch open signal generator SQ/S, and the signal generated thereby is connected to the IDC circuit, and the mark timer circuit M/TIM is not shown in the drawing. The output PTT of the press switch is input, and the mark/timer circuit M・TIM
is the case where there is no microphone M output and the press signal
The squelch open signal generator SQ/S in the next stage is activated to signal the squelch open signal in the initial short time when PTT is input, and intermittently with a certain period if the microphone output continues for more than a predetermined time. The IDC
This is the input to the circuit. Further, 3 is a receiving section of a communication device whose communication partner is the above-mentioned transmitting section 1,
4 is a general receiver consisting of a high frequency section RF, a demodulator DISC, a noise squelch N/SQ, a low frequency amplifier AMR, and a speaker SP.
An AND circuit AND circuit is configured to continuously input a part of the DISC output to the time counter T・C via the filter circuit FIL that detects the squelch open signal and the output of the noise squelch N・SQ. The low frequency amplifier AMP is configured to output the output of the low frequency amplifier AMP to the speaker while detecting the squelch open signal via the squelch open signal and for a predetermined time after this signal disappears.

Next, the operation of the squelch control circuit of the present invention constructed as described above will be explained with reference to the time chart shown in FIG.

Now, when the operator activates the transmitter as shown in FIG. 2a by pressing a press switch (not shown) of the transmitter 1, a part of the signal is input to the mark timer circuit and the The squelch open signal generator is activated to generate a squelch open signal for a short time and superimpose it on the transmission wave. Furthermore, when the microphone output is intermittent as shown in Fig. 2b, it is detected by the voice controller VOK, and as shown in Fig. 2c, it is continuous while there is no microphone output, and if it continues for a certain period of time, it is output at a predetermined interval T. Then, the squelch open signal is sent out intermittently.

On the other hand, the squelch open signal thus sent out is received by the receiver 3, detected by the filter circuit FIL, and its output is input to the time counter T.C. At this time, the time counter T.C outputs a signal indicating that the squelch should be opened while the squelch open signal is present and for a predetermined period of time after it disappears, so this and the output of the noise squelch circuit N.SQ are combined. The low frequency amplifier AMP is operated only when both the above signals are present, and the output thereof is outputted as sound from the speaker SP to the outside.

Therefore, if a squelch open signal is continuously superimposed on the transmitted wave at a predetermined time interval, the receiver that detects this can keep the squelch open continuously during that time and either stop transmission or If the transmission of the squelch open signal is stopped, the receiver closes the squelch by the time counter T/C output or the conventional noise squelch N/SQ function, as shown in Figure 2 c and d, and outputs the audio to the outside. can be stopped.

The squelch open signal used in the present invention may be a single tone signal like the conventional tone squelch, or may be a plurality of parallel tones or other digital signals such as codes based on frequency shift keying system FSK. The squelch open signal sending interval time T should be set slightly shorter than the squelch open time _T1 after the squelch open signal disappears in the receiving side time counter T・C.Furthermore, when using an audible tone as the squelch open signal, frequency amplifier
A filter can be installed in front of the AMP. Furthermore, when the present invention is applied to a communication device equipped with both a transmitter and a receiver, it would be possible to share the mark timer M.TIM on the transmitter side and the time counter T.C on the receiver side.

Since the present invention is configured and operates as described above, the required signal is superimposed on the transmitted wave using the period when there is no modulation signal, and the squelch of the other party's receiver is controlled, so that the call quality is improved like the conventional tone squelch method. Not only does it not cause deterioration, but also an individual selection function can be added by applying specific coding to the squelch open signal, which is extremely effective in improving both the call quality and functionality of wireless communication.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a transmitter and a receiver showing one embodiment of the present invention, and FIGS. 2a to 2d are timing charts showing the operation timing of each part, respectively. 1... Transmitter, 2... Conventional general transmitter,
3... Receiving section, 4... Conventional general receiver,
VOK...Voice controller, M/TIM...Mark/timer circuit, SQ/S...Squelch open signal generator, N/SQ...Noise squelch circuit, FIL
...Filter circuit, T/C...Time counter,
AND...logical product circuit.

Claims (1)

[Claims] 1. A squelch open signal with a predetermined pattern is emitted during a short period when the transmitter is started up and when there is no modulated signal such as an audio signal, and when the modulated signal continues for a certain period of time, a squelch signal is emitted at the required period. An open signal is superimposed on a transmitted wave, and the squelch of the receiver is released for a predetermined period of time while the squelch open signal is detected by a receiver that communicates with the open signal, and for a predetermined time after the detection signal disappears, and the received output is output to the outside. A squelch control method characterized by controlling the squelch function of a receiver to output.