KR100435551B1 - A wireless microphone receiver having mute control function - Google Patents

Abstract

An object of the present invention is to separate the mute control tone signal received with the voice signal, to maintain the mute state from the time of the tone signal input until the set time, and to configure the tone signal detection circuit operable to release the mute, Muting signal detection circuit for mute control of a wireless microphone receiver capable of canceling muting only when a continuous tone signal is inputted and removing short and impulse noises caused by transient external interference propagation in the same frequency range as the tone signal To provide.

The present invention provides a wireless microphone receiving apparatus having a mute control function comprising a CPU, a front end unit, a frequency demodulator, a tone signal detector, and a voice output unit, wherein the tone signal detector is input by LC resonance. A tone signal separator 301 for separating and outputting only the tone signal; A tone decoder 302 for outputting a reset control signal according to a tone signal input from the tone signal separator; A mute time control unit 310 which is reset according to the reset control signal of the tone decoder and controls the mute time so as to be muted after a set time delay upon continuous input of the tone signal; An FM IF IC 303 for outputting any one of an "H" or an "L" signal according to an output signal of the tone decoder; And a control signal output unit 304 for performing a NAND operation on the mute time control unit and the output signal of the FM IF IC to output the mute control signal to the CPU.

Description

A wireless microphone receiver having mute control function

The present invention relates to a wireless microphone receiving apparatus having a mute control function. In particular, the mute control tone signal received together with a voice signal is separated, and the mute state is maintained from the time point at which the tone signal is input until the set time is reached. By configuring a tone signal detection circuit operable to mute, it mutes only when a tone signal is continuously input to remove short noise and impulse noise caused by temporary external interference propagation in the same frequency range as the tone signal. The present invention relates to a mute control tone signal detection circuit of a wireless microphone receiver.

The operation principle of a general wireless microphone is to modulate and transmit a micro-input voice signal into a transmittable high frequency signal, and then demodulate it in a receiving device to output a voice signal.

The wireless microphone transceiver transmits a tone signal of a specific frequency in a non-audible frequency range when transmitting a voice signal in a wireless microphone transmitter in order to remove noise caused by an interference wave of an external device, and in the wireless microphone receiver, When the tone signal is received, it is operated to release the mute and output the received voice signal.

A conventional wireless microphone transceiver having a mute control function will now be described with reference to FIGS. 1 and 2.

1 is a block diagram showing a wireless microphone transmitting apparatus 101 having a conventional mute control function.

In the drawing, a high frequency carrier frequency is generated at the output end of the voice signal processor 110 for amplifying and compressing a voice signal input from the outside under the control of the CPU 151 to generate a voice signal from the voice signal processor 110. A frequency modulator 130 for modulating and outputting a high frequency signal is connected, and an output terminal of the frequency modulator 130 amplifies the modulated high frequency signal and attenuates and transmits spurious radiation. 140 is connected.

The voice signal processing unit 110 includes a microphone 111 for converting an audio signal of an audible frequency band (10 Hz to 20 Hz) input from the outside into an electrical signal and amplifying the electrical signal of the converted audio frequency band to a predetermined size. An automatic amplification controller 112, an amplitude limiter 113 for limiting the signal to a predetermined magnitude or less, a compressor 114 for compressing the amplitude limited signal, and a modulation degree of the compressed signal. Voice signal modulation control unit 115 is included.

In addition, the frequency modulator 130 is connected to the CPU 151 and the PLL 131 whose frequency is determined by the CPU 151, and oscillates the frequency according to the voltage determined by the PLL 131 to the And a VCO 132 for modulating and outputting a voice signal output from the voice signal modulation controller 115 of the voice signal processor 110 into a high frequency signal, wherein the transmitter 140 of the frequency modulator 130 A high frequency power amplifier 141 for amplifying a high frequency signal modulated and output from the VCO 132, and an antenna matcher 142 for attenuating unnecessary radiation of the amplified high frequency signal and transmitting the same to the transmission antenna 143. .

In addition, a tone signal bandpass filter 152 for band-passing an arbitrary mute control tone signal of the inaudible frequency band (30 Hz to 80 Hz) generated by the CPU 151, and the tone signal band pass filter 152. The control signal amplitude adjusting unit 153 is further configured to adjust the magnitude of the tone signal output from the input signal to the frequency modulator 130.

In addition, a booster 154 for boosting and supplying a voltage of the battery power source 122 is further connected to the CPU 151, and a high frequency power amplifier 141 of the transmitter 140 is controlled by a control signal of the CPU 151. The power switch 155 for opening and closing the power of the booster 154 to be supplied is further connected.

The operation of the wireless microphone transmitter 101 having the mute control function configured as described above is as follows.

First, when a user holds a wireless microphone and speaks, a voice signal is induced in the microphone 111, and the voice signal is amplified and amplitude limited through an automatic amplifier controller 112 and an amplitude limiter 113. Compressor 114 is compressed. In addition, the compressed voice signal is modulated through the voice signal modulation controller 115.

In addition, the CPU 151 generates an arbitrary mute control tone signal in the inaudible frequency band (30 Hz to 80 Hz), and the frequency modulator through the tone signal band pass filter 152 and the control signal magnitude adjusting unit 153. Input to the VCO (132) of (130).

At this time, the VCO 132 modulates the mute control tone signal into a high frequency signal determined by the CPU 151 and the PLL 131 together with the voice signal input from the voice signal modulation controller 115. .

The high frequency signal modulated to be transmittable is amplified by the high frequency power amplifier 141, and unnecessary radiation of the high frequency signal is attenuated by the antenna matcher 142 and transmitted through the antenna 143.

FIG. 2 is a block diagram illustrating a conventional wireless microphone receiver 201 having a mute control function, and illustrates a receiver configured in a single superheterodyne manner.

In the drawing, the front end unit 210 receives the high frequency signal received from the wireless microphone transmitter 101 and down converts the intermediate frequency (10.7 MHz) according to the control signal of the CPU 251 to output the same. A frequency demodulator 230 is connected to an output terminal for processing and demodulating the intermediate frequency, and an output terminal of the frequency demodulator 230 amplifies, restores and outputs a voice signal of the demodulated signal. Is connected.

In the above, the front end unit 210 is a low noise amplifier (LNA: 212) for receiving and amplifying a high frequency signal received by the receiving antenna 211, and a divider 213 for distributing the amplified high frequency signal. ), A helical filter 214 for separating the divided signal again, a high frequency amplifier 215 for amplifying the signal again, and a high frequency band for passing a high frequency band among the output signals of the high frequency amplifier 215. A PLL 217 connected to a filter 216, a CPU 251, whose frequency is determined by the CPU 251, and a VCO 218 oscillating a frequency in accordance with a voltage determined by the PLL 217; And an IF converter 219 for mixing the high frequency signal from the high frequency filter 216 with the signal of the VCO 218 and converting the signal into an intermediate frequency.

In addition, the frequency demodulator 230 separates the first IF filter 231 for separating the signal of the IF converter 219, the filter compensation amplifier 232 for amplifying the separated signal, and then separates the signal. A second IF filter 233 and a frequency amplifier and demodulator 234 for amplifying and demodulating the intermediate frequency signal and outputting a voice signal.

In addition, the wireless microphone receiving apparatus 201 separates the mute control tone signal from the output signal of the frequency demodulator 230, and transmits a mute control signal to the CPU 251 after a set time delay when a continuous tone signal is input. It further includes a tone signal detection unit 252 input to.

The CPU 251 monitors the RF level DC voltage of the amplifier and demodulator 234 by an RF level meter output line 253 which is further connected to the amplifier and demodulator 234 of the frequency demodulator 230. It is configured to control the muting time of.

In addition, the audio output unit 240 is connected to the audio signal amplifier 241 for amplifying the demodulated voice signal and the audio signal amplifier 241 and an audio output for switching operation under the control of the CPU 251. When the switch 242 and the audio output switch 242 is turned on, the low frequency filter 243 for passing only the low frequency signal of the signal from the voice signal amplifier 241 and the low frequency filter 243 is connected to the transmission device An inflator 244 for restoring the compressed sound signal at 101 and the inflator 244, switching the output of the sound signal to the speaker 246 under the control of the CPU 251, and It further comprises a sound signal amplification and power switch 245 to amplify.

The operation of the wireless microphone receiver 201 having the mute control function configured as described above is as follows.

First, the high frequency signal received from the wireless microphone transmitter 101 through the reception antenna 211 is amplified by the low noise amplifier 212, distributed and separated through the distributor 213 and the helical filter 214, The amplifier 215 is again amplified and output.

After that, only the high frequency band is passed through the high frequency filter 216 and is input to the IF converter 219 and output signal of the VCO 218 oscillating at a frequency determined by the CPU 251 and the PLL 217. It is mixed and output to the intermediate frequency.

In addition, the converted intermediate frequency signal is separated by the first IF filter 231 of the frequency demodulator 230, amplified and separated through the filter compensation amplifier 232 and the second IF filter 233, frequency The amplification and demodulation unit 234 is amplified and demodulated and output as a voice signal.

The demodulated voice signal is amplified by the voice signal amplifier 241 of the voice output unit 240 and input to the low frequency filter 243 through the audio output switch 242 which is switched under the control of the CPU 251. .

In the low frequency filter 243, only the low frequency signal passes, and the sound signal is restored through the expander 244, the sound signal amplification, and the power switch 245, and then output to the speaker 246.

Here, the tone signal detection unit 252 separates the mute control tone signal from the demodulation signal from the frequency demodulation unit 230 and inputs it to the CPU 251.

At this time, when the tone signal is input, the CPU 251 turns on the audio output switch 242 and the sound signal amplification and power switch 245 to output the audio signal to the speaker 246.

On the contrary, when the tone signal is not input from the tone signal detector 252, the audio signal is output to the speaker 246 by turning off the audio output switch 242 and the sound signal amplification and power switch 245. Block it. In other words, the receiving end is kept muted or muted.

However, the conventional wireless microphone transceiver having a mute control function malfunctions due to temporary interference propagation in the same frequency range as the tone signal, or generates short or impulse noise when used in combination with an external device. there was.

An object of the present invention for solving the above problems is to separate the mute control tone signal received with the voice signal, to maintain the mute state until the set time from the tone signal input time, the tone operating to release the mute By constructing a signal detection circuit, a wireless microphone receiver capable of canceling muting only when a tone signal is continuously input and removing short noise and impulse noise due to transient external interference propagation in the same frequency range as the tone signal To provide a mute control tone signal detection circuit.

1 is a block diagram showing a conventional wireless microphone transmitter having a mute control function.

2 is a block diagram illustrating a conventional wireless microphone receiver having a mute control function.

3 is a block diagram showing a mute control tone signal detection circuit of a wireless microphone receiving apparatus having a mute control function according to the present invention.

4 is a time chart showing input and output signals for each device of the mute control tone signal detection circuit according to the present invention.

※ Explanation of symbols about main part of drawing ※

101: wireless microphone transmitter 201: wireless microphone receiver

110: voice signal processor 111: microphone

112: automatic amplification controller 113: amplitude limiter

114: compressor 115: voice signal modulation control unit

151, 251: CPU 122: battery power

130: frequency modulator 131, 217: PLL

132, 218: VCO 140: transmitter

141: high frequency power amplifier 142: antenna matcher

143: transmission antenna 152: tone signal bandpass filter

153: control signal control unit 154: booster

155: power switch 210: front end

211: reception antenna 212: low noise amplifier

213: Splitter 214: Helical Filter

215: high frequency amplifier 216: high frequency filter

219: IF converter 230: Frequency demodulator

231: first IF filter 232: filter compensation amplifier

233: second IF filter 234: amplification and demodulator

240: voice output unit 241: voice signal amplifier

242: audio output switch 243: low frequency filter

244: expander 245: amplification and power switch

246: speaker 252: tone signal detection unit

253: RF level meter output line 301: tone signal separator

302: tone decoder 303: FM IF IC

304: control signal output unit 310: mute time control unit

311: Timebase OSC 312: Ring Counter

In order to achieve the above object, the present invention is a wireless microphone receiving apparatus having a mute control function consisting of a CPU, a front end unit, a frequency demodulation unit, a tone signal detector and a voice output unit, wherein the tone signal detector is input voice signal and tone A tone signal separator for separating and outputting only the tone signal by LC resonance among the signals; A tone decoder for outputting a reset control signal according to the tone signal input from the tone signal separator; A mute time control unit which is reset according to a reset control signal of the tone decoder and controls a mute time so as to be muted after a set time delay upon continuous input of a tone signal; An FM IF IC for outputting any one of an "H" or an "L" signal according to an output signal of the tone decoder; And a control signal output unit configured to perform a NAND operation on the mute time control unit and the output signal of the FM IF IC to output the mute control signal to the CPU.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

3 is a block diagram showing a mute control tone signal detection circuit of a wireless microphone receiving apparatus having a mute control function according to the present invention.

In the drawing, the mute control tone signal detection circuit includes a tone signal separator 301 which separates and outputs only a tone signal by LC resonance among voice signals and tone signals input and demodulated from the frequency demodulator, and is input from the tone signal separator. A tone decoder 302 for outputting a low ("L") reset control signal when a tone signal is present, and a high ("H") reset control signal when a tone signal is not input, and a reset control of the tone decoder A mute time control unit 310 for controlling the mute time at the time of inputting the tone signal so as to be muted after a set time delay when the tone signal is input continuously and reset according to the signal, and " H " Or a control signal output unit for outputting a mute control signal to the CPU by performing a NAND operation on the FM IF IC 303 for outputting the "L" signal, and the output signals of the mute time control unit 310 and the FM IF IC 303 ( 304).

In addition, the mute time controller 310 is connected to the tone decoder 302 and the time base OSC 311 which is turned on and off in accordance with the reset control signal of the tone decoder 302 to oscillate and stop. And a ring counter 312 which feeds back the reset control signal from the control unit and outputs the signal to the timebase OSC 311, checks the time when the timebase OSC oscillates, and outputs an "H" signal after the set time. .

The operation of the mute control tone signal detection circuit configured as described above is as follows.

First, the tone signal separator 301 demodulates and outputs only a tone signal from an audio signal and a tone signal which are demodulated from the frequency demodulator by LC resonance. The tone decoder 302 outputs a reset control signal as a "L" signal when a tone signal is input from the tone signal separator and as a "H" signal when a tone signal is not input. The ring counter 312 first feeds back the reset control signal output from the tone decoder to the timebase OSC 311. The timebase OSC 311 performs on / off operation according to the reset control signal input by the ring counter to start and stop.

Here, the timebase OSC 311 is turned on when the reset control signal is "L" and oscillates, and is turned off when the reset control signal is "H" to stop the oscillation operation. Only when the oscillation is activated.

The ring counter 312 is reset when the tone decoder 302 is "H", and outputs an "L" signal when the timebase OSC 311 does not oscillate, and the timebase OSC 311. Checks the time during oscillation operation and outputs "H" signal when the set time has elapsed.

On the other hand, the FM IF IC 303 outputs an "H" signal as a SD (Station Detect) signal when the "L" signal is input from the tone decoder 302 and "L" as an SD signal when the "H" signal is input. Signal will be output.

Thereafter, the control signal output unit 304 performs a NAND operation on the ring counter 312 of the mute time controller 310 and the output signals of the FM IF IC 303 to output the mute control signal to the CPU.

Here, since the control signal output unit 304 performs a NAND operation, when both the ring counter 312 and the FM IF IC 303 output the "H" signal, the control signal output unit 304 outputs the "L" signal to the CPU. When the mute is released and the ring counter 312 and the FM IF IC 303 both do not output the "H" signal, the "H" signal is output to the CPU to maintain the mute state.

As a result, since the operation is performed to cancel muting only when a continuous tone signal is input, the short noise or the impulse noise caused by the temporary interference propagation by the external device is removed.

4 is a time chart showing input and output signals for each device of the mute control tone signal detection circuit according to the present invention.

In the figure, section "A" represents an input / output signal for each device due to interference propagation by an external device in the same frequency range as the tone signal, and section "B" represents input / output for each device when continuous tone signals are input. Indicates a signal.

First, referring to the section "A", the reset control signal output from the tone decoder is in the "L" state when the tone signal is input, and in the "H" state when the tone signal is not input.

The output signal of the timebase OSC oscillates when the reset control signal is "L", and stops when "H", and the Qn-out, which is the output of the ring counter, after a set time when a continuous tone signal is input, Since the signal is in the " H " state, the " L " state is maintained in the discontinuous tone signal input section in the " A " section.

The SD signal, which is an output signal of the FM IF IC, becomes "H" when a tone signal is input, and becomes "L" when no tone signal is input.

The mute control signal, which is the output signal of the control signal output unit 304, is maintained in the "H" signal state to maintain the mute on state since both the Qn-out and SD signals are "H" at the same time.

Next, referring to the "B" section, the reset control signal output from the tone decoder maintains the "L" state because the tone signal is continuously input.

The output signal of the timebase OSC continues to oscillate as the reset control signal maintains the " L " state, and the Qn-out, which is the output of the ring counter, receives a continuous tone signal, thus delaying the set ring count time T. After that, the state becomes the "H" signal.

The SD signal, which is the output signal of the FM IF IC, remains "H" according to the continuous tone signal input, and the mute control signal, which is the output signal of the control signal output unit 304, is Qn- after the ring count time (T) delay. As out goes to " H " state, the state goes to the " L " signal state to be muted off after the ring count time T delay.

As described above, according to the mute control tone signal detection circuit according to the present invention, the mute is released after a set time has elapsed during continuous tone signal input.

Although the present invention has been described with reference to the mute control tone signal detection circuit of the type shown in FIGS. 3 and 4, the present invention is not limited thereto, and the mute control tone signal detection circuit is defined in the appended claims. Many other variations and modifications will be possible without departing from the scope of the invention.

As described above, according to the present invention, it is possible to cancel muting only when the tone signal is continuously input, thereby removing the short noise and the impulse noise caused by transient external interference propagation in the same frequency range as the tone signal. have.

Claims (3)

Receives the high frequency signal received from the CPU controlling each device and the wireless microphone transmitter which modulates the audio signal input from the outside into the high frequency signal together with the mute control tone signal and converts it to the intermediate frequency according to the control signal of the CPU. A front end unit for outputting a signal, a frequency demodulator for processing and demodulating the intermediate frequency, a tone signal detector for separating a mute control tone signal from an output signal of the frequency demodulator, and amplifying a voice signal among the demodulated signals And a mute control function comprising a sound output unit for restoring and outputting the sound signal and switching the voice signal output under the control of the CPU. A tone signal separator (301) which separates and outputs only a tone signal by LC resonance among voice signals and tone signals which are input by being demodulated from the frequency demodulator; A tone decoder 302 for outputting a reset control signal according to a tone signal input from the tone signal separator; A mute time control unit 310 which is reset according to the reset control signal of the tone decoder and controls the mute time so as to be muted after a set time delay upon continuous input of the tone signal; An FM IF IC 303 for outputting any one of an "H" or an "L" signal according to an output signal of the tone decoder; And a control signal output unit 304 outputting a mute control signal to the CPU by performing a NAND operation on the mute time control unit and the output signal of the FM IF IC. The mute time control unit 310 of claim 1, wherein the mute time control unit 310 is connected to the tone decoder in response to a timebase OSC 311 which is turned on and off in response to a reset control signal of the tone decoder and starts and stops. And a ring counter 312 which feeds back a reset control signal to the timebase OSC, checks the time when the timebase OSC oscillates, and outputs an "H" signal after a set time. Device. The wireless microphone receiver according to claim 1, wherein the reset control signal is "L" when a tone signal is input and "H" when no tone signal is input.