JPH0823491A - Television receiver - Google Patents

Abstract

PURPOSE:To suppress noise by phase-inverting an extracted noise signal, amplifying it with a prescribed amplification factor, outputting it as a sound wave whose phase is inverse to noise from a speaker and feedback-controlling the sound wave by a difference between a period prior by one, which stores the amplification factor, and a present period. CONSTITUTION:A relation A between the sound volume of television sound and the output of a microphone 1 is previously measured in a noiseless room. The sound output of a sound circuit part 20 is phase-inverted by a sound adjustment part 21, and the output is amplified to a prescribed level based on the relation A. An adding part 2 adds the outputs of the microphone 1 and the adjustment part 21 and compensates a sound signal. A phase inversion part 4 inverts the phase of the extracted noise signal and an amplifier part 5 amplifies the signal. On the other hand, a difference judgement part 10 controls an amplification control part 12 by a result obtained by calculating the difference between the period prior by one and the present period by an arithmetic part 8 from a DC value which a DC generation part 7 generates by rectifying the noise signal by using a memory 11. The control part 12 adjusts the amplification factor of the amplifier part 5, and the speaker 6 feedback-controls the sound wave whose phase is inverse to noise by the prescribed period and outputs it. Thus, the influence of peripheral noise can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver capable of suppressing ambient noise by active sound control and viewing.

[0002]

2. Description of the Related Art Conventionally, television receivers are affected by various noises such as noises in a room in which they are placed, such as noises of cars, coolers, rain sounds, children's voices, and airplane explosions. Was masked and it was difficult to hear. Therefore, I listened to the TV by raising the volume in response to the ambient noise, but the situation of the noise changes.For example, when the noise suddenly disappears, the volume is too loud and the volume is reduced. It was necessary to constantly adjust the volume in response to the noise of the, and there was a troublesome problem.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a television receiver which is not affected by ambient noise.

[0004]

In order to achieve the above object, in a television receiver which processes a video signal and an audio signal to display a reproduced video on a picture tube and outputs a reproduced sound from a speaker. , A microphone for converting sound into an electric signal, a synthesizing unit for synthesizing a television audio signal amplified to a required size and having its phase inverted and the output signal of the microphone, and inverting the phase of the output of the synthesizing unit. A phase inversion unit, an amplification unit that amplifies the output of the phase inversion unit, a speaker that converts the amplified signal into a sound wave, a DC generation unit that generates DC from the output signal of the synthesis unit, and a DC of one cycle or earlier. While updating the calculation unit for calculating the difference between the value and the DC value currently output by the DC generation unit, the timer for measuring a predetermined cycle, and the DC value data generated by the DC generation unit for each cycle. When I remember In addition, a memory for storing the current difference and the difference before one cycle is compared with the current difference and the difference before one cycle to determine whether the difference is in an increasing state or a decreasing state. Units, an amplification control unit that controls the amplification degree of the amplification unit based on the determination result of the difference determination unit, and a control unit that controls each unit.

[0005]

With the above-described structure, the audio signal of the television is phase-shifted by adding, for example, in the synthesizing unit, the television audio signal of a required magnitude in which the phase is inverted to the sound signal captured by the microphone. Is canceled by the added signal, and the output of the synthesizing unit is only the noise signal. The phase inversion unit inverts the phase of this noise signal and amplifies it to a required level, and outputs a sound wave having a phase opposite to that of the noise into the air via the speaker. On the other hand, the DC generator generates DC based on the noise signal, the arithmetic unit calculates the difference from the value of the DC stored one cycle before stored in the memory, and the difference determination unit records one cycle stored in the memory. The tendency of the amplification degree to be adjusted is determined from the previous difference and the current difference, and a control signal for increasing or decreasing the amplification degree is supplied to the amplification control section based on the determination result, and the amplification control section amplifies the amplification section. Adjust the degree. Therefore, based on the noise (DC) value detected by the DC generator, the amplification degree of the amplifier is adjusted every cycle, and feedback control is performed so that the noise is minimized.

[0006]

EXAMPLE A television receiver according to the present invention will be described below.
This will be described in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of a television receiver according to the present invention. Reference numeral 1 is a microphone that converts ambient sound into an electric signal. Reference numeral 2 denotes a television audio signal in which the audio signal output from the audio circuit unit 20 of the television receiver is phase-inverted by the sound adjusting unit 21 and amplified to a required size.
It is a synthesizing unit that adds and synthesizes the output signal of the microphone 1. A switch 3 selects one of the output of the synthesizing section 2 and the zero potential based on a switching signal. Reference numeral 4 is a phase inverting unit that inverts the phase of the output of the synthesizing unit 2. 5
Is an amplifying section for amplifying the output of the phase inverting section 4.
Reference numeral 6 is a speaker that converts the amplified audio signal into a sound wave.

Reference numeral 7 denotes a direct current generating unit for generating direct current from the output signal of the combining unit 2, for example, a rectifier and an integrator connected in cascade to the rectifier. Reference numeral 8 is an arithmetic unit that calculates the difference between the direct current value before one cycle and the direct current value currently output by the direct current generating unit 7. 9 is a timer for measuring a predetermined period. Reference numeral 10 denotes a difference determination unit that compares the current difference with the difference of one cycle or earlier and determines whether the difference is in an increasing state or a decreasing state. Reference numeral 11 denotes a memory that stores the DC value data generated by the DC generator 7 while updating the data for each cycle, and also stores the current difference and the difference before one cycle.

Reference numeral 12 is an amplification control section for controlling the amplification degree of the amplification section 5 based on the judgment result of the difference judgment section 10.
Reference numeral 13 compares the value of the direct current generated by the direct current generator 7 with a reference value, and when the direct current value is larger, a switch signal for the switch 3 to select the output of the combiner 2 is provided. This is a level comparison unit to be generated. A control unit 14 controls each unit.

The operation of the television receiver according to the present invention is shown in FIG.
It will be described with reference to FIGS. In the television receiver according to the present invention, the relationship between the volume of the television sound and the microphone output is measured in advance in a noiseless room or the like, and in the actual noise suppression operation,
Only the noise is extracted by synthesizing the TV sound of the level based on the above relationship with the microphone output in the opposite phase. The graph of FIG. 2 is a conceptual diagram showing the relationship between the microphone output and the volume of television sound measured in a noiseless room or the like. The horizontal axis of FIG. 2 is a volume scale for volume adjustment of the sound output as a sound wave from the speaker (not shown) by the television receiver,
The vertical axis represents the level of a voice electric signal obtained by collecting sound with a microphone. Television sound is emitted at a level corresponding to each volume scale in a noiseless room, and the television sound can be converted into an electric signal by the microphone 1 and taken out. The volume scale and the electric signal level output by the microphone 1 in advance. You can know the relationship.

The actual noise suppressing operation is carried out in consideration of the relationship obtained in the preliminary operation of the noiseless room. The sound signal output from the sound circuit unit 20 of the television receiver is phase-inverted by the sound adjusting unit 21, and is amplified to a level corresponding to the microphone output for the current volume scale based on the relationship of the graph shown in FIG. To generate the audio signal of the TV. The synthesizing unit 2 adds the electric signal obtained by converting the sound around the television receiver output by the microphone 1 and the TV audio signal supplied by the sound adjusting unit 21 to cancel the TV audio signal and reduce only the noise. Take it out.

The phase inverting unit 4 inverts the phase of the noise as shown in FIG. 3D, the amplifying unit 5 amplifies the noise with a required amplification degree, and outputs a sound wave having a phase opposite to the noise from the speaker 6. Noise is suppressed by the sound waves of the opposite phase. DC generator 7
When the noise waveform output by the synthesizing unit 2 and shown in FIG. 3A is input, for example, full-wave rectification is performed to obtain the rectified waveform shown in FIG. The same rectified waveform is integrated, for example, as shown in FIG.
Obtain the DC value shown in (C). The calculation unit 8 calculates the difference between the direct current value before one cycle and the current direct current value. Difference determination unit 1
1 indicates whether the amplification degree should be increased, the amplification degree should be further decreased, or the amplification degree should be held as it is with respect to the adjustment tendency of the amplification degree based on the current difference and the difference before one cycle. Based on the determination result, the amplification control unit 12 is supplied with a control signal for increasing, decreasing, or holding the amplification degree as it is. The amplification control unit 12 adjusts the amplification degree of the amplification unit 5 under the control of the amplification control unit 12. Feedback control is repeated in a predetermined cycle from detection of the noise value to output of a sound wave having a phase opposite to that of the noise.

The DC generated by the DC generator 7 is compared with the reference value shown in FIG. 3C by the level comparator 13, and when the DC value is larger, the switch 3 is connected to the terminal A side. , If the output of the synthesizing unit 2 is selectively output and the DC value is smaller,
The switch 3 may be connected to the B terminal side to selectively output the zero potential. Further, a method in which the DC generator 7 squares the output of the combiner 2 to generate DC or a method of performing half-wave rectification to generate DC from the average may be implemented. Alternatively, the DC generator may include a low-pass filter, a rectifier, and an integrator, and the signal waveform of the low-frequency signal may be averaged to generate a DC value.

FIG. 4 is a block diagram of another embodiment of the television receiver according to the present invention. The same parts as those in the block diagram of the embodiment of the television receiver according to the present invention shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 22 is a phase adjustment unit that inputs the audio signal of the television, which has been amplified by the audio adjustment unit 21 to a required level and has its phase inverted, and adjusts and outputs the phase. The operation of the phase adjustment unit 22 will be described. Figure 5 (a) shows
FIG. 5B shows a waveform obtained by delaying the phase of the audio signal of the TV, which has been amplified by the audio adjuster 21 to a required level and has its phase inverted, by Δ, and FIG. The output signal of the microphone 1 which is converted into an electric signal,
FIG. 3 is a diagram showing a phase relationship with a phase-adjusted television audio signal output by the phase adjuster 22, and shows two waveforms in a state in which the phases are completely adjusted to opposite phases. In another embodiment of the television receiver according to the present invention, by adding these two waveforms in the synthesizing unit 2, the audio signal of the television is completely canceled, and the synthesizing unit 2 outputs only the noise signal. it can.

[0014]

As described above, the present invention provides a television receiver that is not affected by ambient noise. Therefore,
There is an advantage that the annoyance of adjusting the volume according to the change of the noise level by listening to the TV by increasing the volume according to the ambient noise and the noise situation can be eliminated. Further, the present invention can be applied not only to the television receiver described above, but also to a device such as a radio that outputs audio.

[Brief description of drawings]

1 is a block diagram of an embodiment of a television receiver according to the present invention.

FIG. 2 is a conceptual diagram showing a relationship between a microphone output and a sound volume of TV sound measured in a noiseless room or the like of the television receiver according to the present invention.

FIG. 3 Noise level (level) of the television receiver according to the present invention
It is a signal waveform of each part of a detection and noise suppression operation.

FIG. 4 is a block diagram of another embodiment of a television receiver according to the present invention.

FIG. 5 is a diagram illustrating the phase relationship between the output signal of the microphone and the audio signal of the television after phase adjustment in another embodiment of the television receiver according to the present invention.

[Explanation of symbols]

 1 Microphone 2 Synthesis part 3 Switch 4 Phase inversion part 5 Amplification part 6 Speaker 7 DC generation part 8 Calculation part 9 Timer 10 Difference judgment part 11 Memory 12 Amplification control part 13 Level comparison part 14 Control part 20 Voice circuit part 21 Sound adjustment part 22 Phase adjuster

Claims (7)

[Claims] 1. A television receiver for processing a video signal and an audio signal respectively to display a reproduced video on a picture tube and outputting a reproduced sound from a speaker, and a microphone for converting the sound into an electric signal. , A phase inversion unit for inverting the phase of the output of the microphone, and a phase inversion unit for inverting the phase of the output signal of the microphone, and an amplification of the output of the phase inversion unit. An amplification unit, a speaker that converts the amplified signal into a sound wave, and a DC generation unit that generates DC from the output signal of the synthesis unit,
A calculation unit that calculates the difference between the DC value of one cycle or earlier and the DC value currently output by the DC generation unit, a timer that measures a predetermined cycle, and the DC value data generated by the DC generation unit The difference is in an increasing state or a decreasing state by comparing the current difference and the difference before 1 cycle with the memory that stores the current difference and the difference before 1 cycle while updating while storing for each cycle. A television receiver including a difference determining unit that determines whether the difference is present, an amplification control unit that controls the amplification degree of the amplification unit based on the determination result of the difference determining unit, and a control unit that controls each unit. 2. The direct current generating unit is composed of a rectifier and an integrator connected in series to the rectifier, and direct current is generated from an average of signal waveforms obtained by rectifying an output signal of the combining unit. A television receiver according to item 1. 3. The low-pass filter in the DC generator,
The television receiver according to claim 1 or 2, wherein the television receiver comprises a rectifier and an integrator, and generates direct current from an average of signal waveforms of low-frequency signals. 4. A television receiver which reproduces a video signal and an audio signal to display the video on a picture tube and outputs the sound from a speaker, and a microphone for converting the sound into an electric signal and a required size. A synthesis unit for synthesizing the audio signal of the television and the output signal of the microphone which are amplified and inverted in phase, and a switch for selecting which of the output of the synthesis unit and the zero potential based on the switching signal,
A phase inverting unit that inverts the phase of the output of the synthesizing unit, an amplifying unit that amplifies the output of the phase inverting unit, a speaker that converts the amplified signal into a sound wave, and a DC that generates DC from the output signal of the synthesizing unit. The generator generates a switching signal for comparing the value of the direct current generated by the direct current generator with a preset reference value, and when the direct current value is larger, the switch selects the output of the combiner. A level comparing section, a calculating section for calculating a difference between a direct current value before one cycle and a direct current value currently output by the direct current generating section, a timer for measuring a predetermined cycle, and a direct current generated by the direct current generating section. A memory for storing the value data while updating the data for each cycle and storing the difference between the direct current value before one cycle and the current direct current value, and the current difference and 1
A difference determination unit that determines whether the difference is in an increasing state or a decreasing state by comparing with the difference before the cycle, and an amplification control unit that controls the amplification degree of the amplification unit based on the determination result of the difference determining unit. And a television receiver that includes a control unit that controls each unit. 5. The television receiver according to claim 1, wherein the DC generator generates a DC by averaging the outputs of the combiner. 6. The television receiver according to claim 1 or 2, wherein the DC generator generates an absolute value of the output of the combiner and generates a DC from the average thereof. 7. A television receiver for processing a video signal and an audio signal respectively to display a reproduced video on a picture tube and outputting a reproduced sound from a speaker, and a microphone for converting the sound into an electric signal, A phase adjustment section for inputting and outputting a phase-adjusted television audio signal that has been amplified and amplified in the magnitude of the above, and the phase-adjusted television audio signal output by the phase adjusting section and the microphone output signal. , A phase inverting unit that inverts the phase of the output of the synthesizing unit, an amplifying unit that amplifies the output of the phase inverting unit, a speaker that converts the amplified signal into a sound wave, and an output of the synthesizing unit. A direct current generating part for generating direct current from a signal; a computing part for calculating a difference between a direct current value before one cycle and a direct current value currently output by the direct current generating part; a timer for measuring a predetermined period; Generated by the generator Stores while updating every period data of the DC value, the current difference and the 1
The memory that stores the difference before the cycle and the current difference and 1
A difference determination unit that determines whether the difference is in an increasing state or a decreasing state by comparing with the difference before the cycle, and an amplification control unit that controls the amplification degree of the amplification unit based on the determination result of the difference determining unit. And a television receiver that includes a control unit that controls each unit.