KR200151591Y1 - Automatic sound mute device of a television - Google Patents

Abstract

The present invention relates to an audio mute device of a television receiver, and relates to an automatic audio mute device of a television receiver that can mute an audio signal output through a speaker in a non-signal state without a video signal, such as when switching channels. A television receiver having automatic gain control means for outputting an automatic gain control voltage for controlling gain of a broadcast signal on the basis of a level of a received video signal, the automatic gain voltage detecting a voltage output from the automatic gain control means. And a mute signal generating means for generating a mute signal for muting the audio signal when the detecting voltage by the automatic gain voltage detecting means rises above a predetermined reference voltage. The mute signal generating means can be set to vary the reference voltage Characterized in that configured.

Description

Automatic voice mute device for television receiver

1 is a block diagram showing the internal configuration of a general television receiver.

2 is a block diagram showing the internal configuration of a television receiver including an automatic audio mute device according to an embodiment of the present invention.

3 is a circuit diagram showing an example of the configuration of the AGC voltage detector 210 and the mute signal generator 220 in FIG.

FIG. 4 is a circuit diagram showing another example of the configuration of the AGC voltage detector 210 and the mute signal generator 220 in FIG.

* Explanation of symbols for main parts of the drawings

1 antenna 2 RF (Radio Frequency) amplifier

3: mixer 4: IF amplifier

5: P / S separator 6: voice detector

7: Image detector 8: Remote control device

9: Receiver 10: Channel Memory

11: microprocessor

12: PWM (Pulse Width Modulation) generator

13: integrating circuit

14 AFT circuit 15 adder

16: local oscillation circuit 17: AGC circuit

18: voice processing unit 19: voice amplifier

20: speaker 21: image processing unit

22: CRT drive unit 23: CRT

210: AGC voltage detector 220: mute signal generator

AND1: logical product operation R1, R2, R3, R4: resistance

VR1, VR2: Variable resistor D1: Diode

C1: Capacitor TR1: Transistor

CP1: comparator

The present invention relates to an audio mute device for a television receiver, and more particularly, to an automatic audio mute device for a television receiver that can mute an audio signal output through a speaker in a non-signal state such as when switching channels. .

1 is a block diagram showing the internal configuration of a general television receiver.

In the drawing, reference numeral 1 denotes an antenna for receiving an airwave broadcasting signal, 2 denotes an RF amplifier for amplifying an RF signal received through the antenna 1, and 3 denotes an RF signal from the RF amplifier 2; A mixer for generating an intermediate frequency signal (IF signal) by mixing the oscillation frequency from the local oscillation circuit 16 to be described later.

Reference numeral 4 denotes an IF amplifier for amplifying the IF signal output from the mixer 3, and 5 denotes an image intermediate frequency (PIF) signal and an audio intermediate frequency from the IF signal output from the IF amplifier 4; A P / S separation unit configured to separate (SIF) signals, for example, a surface acoustic wave filter, etc., 6 is an audio detector for detecting an audio signal from the SIF signal, and 7 is an image detector for detecting an image signal from the PIF signal. .

In addition, reference numeral 8 is a remote control device for selecting a channel desired by the viewer or performing a volume control, 9 is a receiving unit for converting an infrared signal from the remote control device 8 into an electric code signal, and 10 is a predetermined The channel memory 11 storing the channel data is a microprocessor which controls the whole device in accordance with the remote control signal from the remote control device 8.

Reference numeral 12 denotes a PWM generator which generates a predetermined Pulse Width Modulation (PWM) signal according to the control signal from the microprocessor 11, and 13 denotes an output from the PWM generator 12. An integrated circuit for integrating a PWM signal to generate a predetermined level signal. When the viewer selects a predetermined channel using the remote controller device 8, the microprocessor 11 converts channel data corresponding to the channel selected by the viewer. After reading from the channel memory 10 and controlling the PWM generator 12 based on this, through the integrating circuit 13 outputs a predetermined voltage control signal corresponding to the channel selected by the viewer.

In addition, reference numeral 14 denotes an automatic fine tuning circuit (AFT) provided for precise tuning operation, and 15 denotes a voltage signal applied from the integrating circuit 13 and an output from the AFT circuit 14. An adder for adding a voltage signal, 16 is a local oscillation circuit, which generates a predetermined frequency signal according to the level of the voltage signal applied through the adder 15 and applies it to the mixer 3 to execute a broadcasting station. .

On the other hand, in the television receiver, the magnitude of the input signal received through the antenna 1 is changed due to the strength or fluctuation of the reception signal, and reference numeral 17 denotes an image detected by the image detector 7. An automatic gain control for controlling the output level of the image signal from the image detector 7 by controlling the amplification degree of the RF amplifier 2 and the IF amplifier 4 based on the level of the signal; AGC) circuit.

Subsequently, reference numeral 18 denotes a base, treble, and volume according to a control signal from the microprocessor 11 although not shown for the voice signal output from the voice detector 6. And a voice amplifier for amplifying the voice signal processed by the voice processor 18 and outputting the voice signal to the speaker 20.

Although reference numeral 21 is not shown for an image signal output from the image detector 7, color, tint, and brightness are in accordance with a control signal from the microprocessor 11. ) And an R (Red), G (Green), B (Blue) signal corresponding to the video signal, and 22 is a CRT (based on the RGB signal output from the image processor 21). 23) CRT drive unit for driving.

That is, in the television having the above-described configuration, when the viewer selects the numeric key of the remote control device 8 or selects the channel up / down key to execute the broadcasting channel selection, the microprocessor 11 causes the channel memory 10 to execute. By reading out the channel data corresponding to the channel selected from the control by the PWM generation unit 12, it is possible to execute the international language for the broadcast channel. The channel broadcast signal tuned in this way is detected by the voice detector 6 and the image detector 7 and output through the speaker 20 and the CRT 23.

By the way, in the above-described television, when the viewer selects a channel without a broadcast signal, or when a non-broadcast channel is selected when the channel up / down key is operated, or when there is no broadcast signal, the viewer, for example, has an on / off timer function. When the television is turned on to set the signal, a noise signal is output through the speaker 20 and the CRT 23, so that the viewer may feel uncomfortable.

Therefore, recently, a voice muting device has been introduced, which detects a synchronization signal included in a video signal and mutes the audio output to a speaker when there is no synchronization signal.

However, in the voice mute apparatus, even when no signal channel is selected, when a broadcast signal of an adjacent channel is mixed and a synchronization signal is detected, the voice mute is not performed, so that a noise signal is output through the speaker. In addition, there is a problem that the channel broadcasting cannot be watched because the voice mute state is repeatedly turned on / off due to an uncertain synchronous detection state in an area where the radio environment is poor, such as when there is a large mountain around the airport.

Accordingly, the present invention has been made to solve the above problems, to provide an automatic voice mute device of a television receiver that can accurately perform the voice mute function in the no signal state, and also actively cope with the surrounding radio wave environment. The purpose is.

In an automatic audio mute apparatus of a television receiver according to the present invention for achieving the above object, in the television receiver having automatic gain control means for controlling to maintain a constant output level of the detected video signal, the automatic gain control means An automatic gain voltage detection means coupled with a resistor to detect the voltage output from the automatic gain control means, and a variable resistor for varying the detected voltage in parallel with the resistance; Comparator for generating a reference voltage through the series combination of the comparison voltage is compared with the detection voltage output from the automatic gain voltage detecting means through the comparator to output a predetermined mute signal when the detection voltage is more than the reference voltage It characterized in that it comprises a mute signal generating means.

In addition, the mute signal generating means is characterized in that it is configured to vary and set the reference voltage.

That is, according to the present invention having the above-described configuration, since the audio mute function is executed based on the automatic gain voltage according to the level of the detected video signal, more reliable audio mute can be performed. In addition, since the reference level of the automatic gain voltage on which the audio mute is performed can be set variably as needed, it is possible to proactively cope with the radio wave environment in the region where the television receiver is installed.

First, the basic concept of the present invention will be described.

As described in FIG. 1, in general, in the television receiver, the AGC circuit 17 is employed to keep the level of the composite video signal detected by the video detector 7 constant at all times. The AGC circuit 17 supplies a voltage signal that is inversely proportional to the level of the image signal detected by the image detector 7, that is, a high control voltage when the image signal level is low, the RF amplifier 2 and the IF amplifier 4. It is applied to increase the signal amplification.

Therefore, when no signal state or the received broadcast signal level is poor, the AGC voltage becomes higher than the predetermined value. In the present invention, the AGC voltage is detected to be higher than the predetermined value. The signal is to be muted.

That is, in FIG. 2, when the AG C voltage detector 210 detects the AGC voltage output from the AGC circuit 17 and the voltage detected by the AGC voltage detector 210 is higher than or equal to a predetermined level, a predetermined mute signal is applied. A mute signal generation unit 220 for generating and outputting is provided, and the mute signal output from the mute signal generation unit 220 is multiplied by the mute signal output from the microprocessor 11 and the AND circuit AND1, and is voiced. It is configured to be applied to the mute signal input terminal MUTE of the processing unit 18.

Here, the multiplication of the mute signal output from the mute signal generator 220 and the microprocessor 11 takes into account a case where the mute signal is at a low level, and if the mute signal is set at a high level, the mute signal It is preferable to OR the mute signal of the generation unit 220 and the microprocessor 11.

FIG. 3 is a circuit diagram showing the configuration of the AGC voltage detector 210 and the mute signal generator 220 in FIG. 2. The AGC voltage detector 210 ₁ provides a resistor R1 to the AGC circuit 17. In FIG. The variable resistor VR1 is coupled in parallel so as to vary the detection voltage applied to the mute signal generation unit 220 ₁ according to the radio wave environment of the region where the television receiver is installed. It is grounded.

In addition, in FIG. 3, the mute signal generator 220 ₁ is basically turned off when the detection output of the AGC voltage detector 210 ₁ is above a predetermined level, thereby outputting a low level mute signal ( TR1). The minimum operating voltage switch diode D1 is coupled to the collector side of the transistor TR1, and the ripple cancellation capacitor C1 is coupled and grounded in parallel with the diode D1.

That is, in the above configuration, when the level of the video signal detected by the video detector 7 is significantly lowered due to no signal condition or the like, the AGC voltage output from the AGC circuit 17 is large. When the detection voltage set by the variable resistor VR1 of the AGC voltage detector 210 ₁ rises above a certain level and exceeds the threshold of the transistor TR1, the transistor TR1 is turned off. The low level mute signal is output.

Therefore, when the viewer selects the non-signal channel at the time of channel switching, the audio signal output to the speaker 20 is muted, thereby preventing noise output to the speaker 20 in the no signal state.

FIG. 4 is a circuit diagram showing another configuration example of the AGC voltage detector 210 and the mute signal generator 220 in FIG. ₂ , which is used to transfer the AGC voltage detector 210 ₂ to the resistors R2 and R3. Comprising a voltage divider circuit, the mute signal generator 220 ₂ generates a reference voltage using the resistor R4 and the variable resistor VR2, and the reference voltage and the detected voltage by the AGC voltage detector 210 ₂ . Is compared with a comparator (CPI) so that a low level mute signal is output when the detected voltage becomes higher than the reference voltage.

In addition, the variable resistor VR2 of the mute signal generator 220 ₂ is configured to variably set the reference voltage according to the radio wave environment.

That is, in the configuration of FIG. 4, as in the configuration of FIG. 3 described above, when the AGC voltage rises above a certain level, a low level mute signal is output to mute the audio signal output to the speaker 20 in the no signal state. do.

As described above, according to the present invention, when a noise signal is output through a speaker due to a non-signal state or the like, it is possible to realize an automatic audio mute device of a television receiver that can improve the viewing environment of a viewer by muting it.

In addition, the present invention is not limited to the above embodiments and can be carried out in various modifications without departing from the technical gist of the present invention.

Claims (1)

A television receiver having automatic gain control means for controlling the output level of a detected video signal to be kept constant at all times, the television receiver having a resistance coupled to the automatic gain control means for detecting a voltage output from the automatic gain control means; Automatic gain voltage detection means having a variable resistor for varying the detection voltage coupled in parallel with the resistor, and a comparator for generating a reference voltage through series coupling of a resistor and a variable resistor to the power supply voltage. And a mute signal generating means for outputting a predetermined mute signal when the detected voltage is greater than or equal to the reference voltage by comparing the detected voltage output from the automatic gain voltage detecting means with the reference voltage. Device.