KR100324747B1 - Circuit for removing noise of voice - Google Patents

Abstract

The present invention relates to a speech noise signal removal circuit and a method for removing the noise. In the related art, many noise components contained in a speech signal have high-pitched components. Therefore, in the present invention, the signal switching unit 400 selects and outputs an audio signal or an external audio signal from the outside from the channel signal selected through the tuner 100 and the audio signal output from the signal switching unit 400. The signal component detector 1000 detects the bass signal component and the treble signal component, and the difference between the bass signal component and the treble signal component detected by the signal component detector 1000, and calculates the AGC voltage of the tuner. A microcomputer 500 that detects and determines a weak electric field and adjusts a high frequency characteristic and a volume of a voice signal according to a difference between signal components and a weak electric field, and the microcomputer when the difference between the signal components is a predetermined value or a weak electric field. A low-pitched / high-pitched controller 600 which reduces noise for controlling high-frequency characteristics by controlling 500, and there is no difference between the signal components or lowers the volume during weak electric field By configuring the volume controller 700 to reduce the noise, by removing the noise component by controlling the frequency characteristics of the audio signal depending on the signal state and the electric field state, to one to be able to play the clean speech signal.

Description

Voice noise signal cancellation circuit {CIRCUIT FOR REMOVING NOISE OF VOICE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice noise signal removal circuit for removing noise components from a voice signal. In particular, the present invention relates to a voice noise signal removing circuit for removing noise components by varying the frequency characteristics of voice signals according to signal and electric field conditions. The present invention relates to a speech noise signal cancellation circuit capable of reproducing an audio signal.

1 is a diagram of a conventional audio signal reproduction circuit. As shown in FIG. 1, a voice detector 20 for detecting a voice signal from a signal of a selected channel through the tuner 10 and an external signal from an external source are input. The external signal input unit 30, the signal switching unit 40 for selecting the voice signal detected through the voice detector 20 or the external signal input through the external signal input unit 30, and the user's adjustment The microcomputer 50 adjusts the magnitude of the signal component and outputs a control signal for adjusting the sound volume, and the signal switching unit 40 is selected according to the signal size adjustment signal of the microcomputer 50. The bass / treble control unit 60 adjusts the magnitude of the bass signal component or treble signal component of the signal, and the magnitude of the signal component in the bass / treble control unit 60 is adjusted in accordance with the sound volume adjustment signal of the microcomputer 50. A volume controller 70 for adjusting the volume of the adjusted signal, an amplifier 80 for amplifying and outputting a signal output from the volume controller 70 to a predetermined level, and a signal amplified by the amplifier 80. It consists of a speaker 90 for reproducing acoustic sound.

Looking at the prior art configured in this way in detail as follows.

The tuner 10 selects a channel desired by the user, and provides the selected signal to the voice detector 20.

Then, the voice detector 20 detects a voice signal from the signal selected by the tuner 10.

At this time, when the voice signal is detected, the detected voice signal is provided to the signal switching unit 40.

When the voice signal is provided to the signal switching unit 40 as described above, the external signal input unit 30 also provides an external signal to the signal switching unit 40.

Thereafter, the signal switching unit 40 selects a voice signal of the voice detector 20 or an external signal of the external signal input unit 30 and transmits the selected signal to the bass / treble controller 60.

At this time, the microcomputer 50 recognizes when the user selects the signal component size and volume using a dial, and outputs a signal size adjustment signal to the bass / treble controller 60 to adjust the selected signal component size and volume. The volume controller 70 outputs a sound volume adjustment signal.

Therefore, the bass / treble controller 60 adjusts the magnitude of the bass signal component or the treble signal component according to the signal size adjustment signal provided by the microcomputer 50 and provides it to the volume controller 70.

Accordingly, the volume controller 70 adjusts the sound volume of the signal in which the bass or treble signal is adjusted by the bass / treble controller 60 according to the sound volume adjustment signal provided by the microcomputer 50. To provide.

Then, the amplifier 80 receives a signal whose signal component and sound volume are adjusted and adjusts the signal level to be output from the speaker 90 to the speaker 90.

Therefore, the speaker 90 is reproduced as acoustic sound.

However, in the prior art as described above, since the voice frequency characteristics are determined in a circuit, there are a lot of noise components contained in the voice signal, and thus there is a problem that noise is easily heard when it is reproduced as it is.

Accordingly, an object of the present invention for solving the conventional problems as described above is to detect the level of the high and low components, respectively, and compare the detected levels, if the high signal level is less, reduce the high frequency characteristics to reduce noise To provide a voice noise signal cancellation circuit to remove.

Another object of the present invention is to provide a voice noise signal removal circuit for detecting an automatic gain control (AGC) voltage of a tuner to reduce noise by reducing high frequency characteristics in the case of a weak electric field.

It is still another object of the present invention to provide a voice noise signal elimination circuit capable of reproducing a much cleaner voice signal by removing noise.

1 is a conventional audio signal reproduction circuit diagram.

2 is a voice noise signal cancellation circuit of the present invention.

3 is a flowchart of operation of the microcomputer in FIG. 2;

Fig. 4 is a first embodiment of the speech noise signal cancellation circuit of the present invention.

Fig. 5 is a second embodiment of the speech noise signal cancellation circuit of the present invention.

***** Explanation of symbols for main parts of drawing *****

100: tuner 200: voice detector

300: external signal input unit 400: signal switching unit

600: bass / treble control unit 700: volume control unit

800: amplifier 900: speaker

500: microcomputer 910: low pass filter

920,940: level detector 930: high pass filter

The present invention for achieving the above object is a signal switching unit for selecting and outputting a voice signal of the voice detection unit for detecting a voice signal from the signal of the channel selected through the tuner or an external signal of the external signal input unit, and the voice of the signal switching unit A signal component detector for detecting a low tone signal component and a high tone signal component from a signal, and obtaining a difference between the low signal component and a high signal component detected above, and detecting AGC voltage of the tuner to determine whether a weak electric field is present Microcomputer to adjust the high frequency and volume of the voice signal according to the difference and weak electric field of the signal, the low / high sound control unit to adjust the high frequency characteristics if the signal component is large or weak electric field If it is to reduce the noise by adjusting the volume of the audio signal output from the bass / treble control unit And a volume controller for amplifying and outputting the picker.

Hereinafter, look at on the basis of the accompanying drawings as follows.

FIG. 3 is a flowchart illustrating a method for removing a voice noise signal according to an embodiment of the present invention. As shown in FIG. 3, a first step of obtaining levels of a high sound signal component and a low sound signal component from a voice signal, and the AGC voltage of the tuner are shown. A second step of detecting a level of the weak electric field by detecting a level; and a third step of reducing noise by reducing the volume in half when the level of the high and low signal components is close to zero or the weak electric field; and A fourth step of obtaining a level difference between the high-pitched signal component and a low-tone signal component if the level is equal to or greater than a predetermined value; and a fifth step of reducing the noise component by lowering the high-frequency frequency characteristic of the voice signal if the level difference obtained is equal to or greater than the predetermined value or a weak electric field; Characterized in that consisting of.

As such, the block configuration of the voice noise signal removing circuit of the present invention for performing the method consisting of each step is, as shown in Figure 2, the voice to detect the voice signal from the signal of the channel selected through the tuner 100 The detector 200, an external signal input unit 300 for inputting an external signal from the outside, and an external signal input through the voice signal or the external signal input unit 300 detected through the voice detector 200. A signal switching unit 400 for selecting a signal component, a signal component detecting unit 1000 for detecting a high tone signal component and a low tone signal component from a signal output from the signal switching unit 400, and the signal component detecting unit 1000 The difference between the bass signal component and the treble signal component detected through is obtained, and the difference is adjusted to adjust the treble frequency characteristics, and the AGC voltage of the tuner 100 is input to check the weak electric field. When the difference between the low frequency signal component and the high frequency signal component obtained by the microcomputer 500 and the microcomputer 500 that adjusts the high frequency characteristics according to the detection unit is high, the high frequency characteristic of the output signal of the signal switching unit 400 When the AGC voltage of the tuner obtained from the microcomputer 500 and the tuner obtained by the microcomputer 500 is a weak electric field, the volume of the signal output from the bass / treble controller 600 is reduced to reduce noise. The volume control unit 700 to amplify, the amplifier 800 to amplify and output the signal output from the volume control unit 700 to a predetermined level, and the speaker for reproducing the acoustic sound of the signal amplified by the amplifier 800 ( 900).

The signal component detecting unit 1000 has a low pass filter 910 for detecting a low sound component by low-passing the voice signal input from the signal switching unit 400, and a low sound component detected by the low pass filter 910. A level detector 920 for detecting a level of the signal and providing it to the microcomputer 500, a high pass filter 930 for detecting a high sound component by high-passing the voice signal, and a high pass filter 930 And a level detector 940 for detecting the level of the high-pitched sound component and providing it to the microcomputer 500.

FIG. 4 is a first embodiment of the voice noise signal removing circuit of the present invention. As shown therein, the voice detector 200 detects a voice signal from a signal of a channel selected through the tuner 100, and an external device. An external signal input unit 300 for inputting an external signal from the signal switch, and a signal switching unit for selecting an external audio signal input through the external signal input unit 300 or a voice signal detected through the voice detector 200 ( 400, a high sound component detection unit 970 for detecting a high sound signal component by high-passing the voice signal selected by the signal switching unit 400, and a signal switching unit 400 for detecting the level of the high sound signal component. If the volume control unit 700 controls the volume of the voice signal selected by the user and the high sound component detected by the high sound component detector 970 is small, the resistance value of the voltage variable resistor 950 increases, thereby increasing the volume control unit. Article 700 A low pass filter 960 for reducing noise components by lowering high frequency characteristics of a voice signal, an amplifier 800 for amplifying and outputting a signal output from the low pass filter 960 to a predetermined level, and the amplifier 800. The speaker 900 for reproducing the acoustic sound of the signal amplified by.

FIG. 5 is a second embodiment of the speech noise signal removing circuit of the present invention. As shown therein, the voice detector 200 detects a voice signal from a signal of a channel selected through the tuner 100, and An external signal input unit 300 for inputting an external signal from the outside, and a signal switching unit for selecting an external audio signal input through the external signal input unit 300 or a voice signal detected through the voice detector 200. 400, the volume control unit 700 controlling the volume of the voice signal selected by the signal switching unit 400 by the user's adjustment, and the voltage variable proportionally as the AGC voltage of the tuner 100 increases. A low pass filter 960 for reducing a noise component by lowering high frequency characteristics of a voice signal provided by the volume controller 700 by increasing a resistance value of the resistor 950 and a signal output from the low pass filter 960 at a predetermined level. Amplify An amplifier 800 to output and a speaker 900 for reproducing the acoustic sound of the signal amplified by the amplifier 800.

When described in detail with respect to the operation and effect of the present invention configured as described above.

The tuner 100 selects a channel desired by the user, and provides the selected signal to the voice detector 200.

Then, the voice detector 200 detects a voice signal from the signal selected by the tuner 100.

In this case, when the voice signal is detected, the detected voice signal is provided to the signal switching unit 400.

When the voice signal is provided to the signal switching unit 400 as described above, the external signal input unit 300 also provides an external signal to the signal switching unit 400.

Thereafter, the signal switching unit 400 selects a voice signal of the voice detector 200 or an external voice signal of the external signal input unit 300 and transmits the selected voice signal to the bass / treble controller 600.

At this time, the low pass filter 910 of the signal component detecting unit 1000 low pass the voice signal output from the signal switching unit 400 to obtain a low tone signal component, and the high pass filter 930 high pass the voice signal. Obtain the treble signal components.

Then, the level detector 920 detects the level A of the low tone signal component and provides it to the microcomputer 500, and another level detector 940 detects the level B of the high tone signal component and Provided at 500.

In addition, the microcomputer 500 detects the AGC voltage of the tuner 100 and obtains a level C for the detected AGC voltage.

The microcomputer 500, which has obtained the level A of the low tone signal component, the level B of the high tone signal component, and the level C of the AGC voltage, performs the operation as shown in FIG.

That is, the microcomputer 500 reads the level A of the low tone signal component, the level B of the high tone signal component, and the level C of the AGC voltage, respectively (S101).

After reading in this way, it is determined whether the level A of the low tone signal component and the level B of the high tone signal component are close to '0' or have a predetermined value, and the C level is checked to determine whether or not the weak electric field is present. (S102)

If the level (A) of the low tone signal component and the level (B) of the high tone signal component are close to '0', it is determined that there is a signal. In addition, when the level (C) of the AGC voltage is the maximum (max) or more than a predetermined level (limit level) it is determined as a weak electric field.

In step S102, if the level A of the low tone signal component and the level B of the high tone signal component are no-signal or weak electric field close to '0', the microcomputer 500 controls the volume control unit 700 to control the volume. Lower to ½ level to reduce loud noise caused by noise.

If the level A of the low tone signal component and the level B of the high tone signal component are each greater than or equal to a predetermined value in step S102, the microcomputer 500 detects the level difference AB between the two signal components. S104)

As a result of the detection, if the level difference is large, it indicates that the signal is low in the high-pitched components. Therefore, the microcomputer 500 controls the low / high-pitched controller 600 to lower the high-pitched level corresponding to the level difference AB, thereby improving the high-frequency characteristics. To be lowered.

This can relatively reduce the noise component.

In addition, if the AGC voltage level is higher than the limit level recognized as the weak electric field, the channel signal is a weak electric field, and the high frequency level is lowered by lowering the high sound level corresponding to the difference between the AGC voltage level and the limit level. Reduce the noise component.

As described above, the low / pitched controller 600 lowers the high frequency characteristic of the voice signal output from the signal switcher 400 under the control of the microcomputer 500, and the low / pitched controller 600 is controlled by the volume controller 700. By controlling the volume of the audio signal output from the reduced noise provided to the amplifier (800).

Then, the amplifier 800 adjusts the voice signal with reduced noise to a predetermined level and reproduces the audio sound through the speaker 900.

And, as shown in Figure 4 with respect to the embodiment that can be used even when there is no bass / treble controller as follows.

A low pass filter 960 is configured by connecting a voltage variable resistor 950 in series between the volume controller 700 and the amplifier 800, and connecting a capacitor C1 to ground at an input terminal of the amplifier 800.

When the signal switching unit 400 selects and outputs a voice signal detected through the tuner 100 and the voice detector 200 or an external input signal input through the external signal input unit 300, the volume controller 700 outputs the selected signal. And the high pass filter 930 of the high sound component detector 970 are respectively input.

The volume control unit 700 receiving the voice signal adjusts the volume of the voice signal received through the signal switching unit 400 by the user's adjustment and then supplies it to the low pass filter 960.

In this case, the high pass filter 930 high-passes the voice signal selected by the signal switching unit 400 to detect the high sound signal component, and the level detector 940 detects the level of the high sound signal component detected by the high pass filter 930. Is detected and provided to the low pass filter 960.

That is, if the level of the high frequency signal component detected by the level detector 940 is small, the resistance value of the voltage variable resistor 950 of the low pass filter 960 is increased. The resistance value of 950 is made small.

When the level of the treble signal component is small so that the voltage variable resistor 950 increases, the treble frequency characteristic of the voice signal output from the volume controller 700 is lowered.

Accordingly, the noise can be reduced.

When the channel signal is a weak electric field, as shown in FIG. 5, the AGC voltage of the tuner 100 is high, and when the AGC voltage is high, the resistance value of the voltage variable resistor 950 increases in proportion to the AGC voltage.

As the voltage variable resistor 950 increases, the frequency characteristic of the low pass filter 960 lowers a high-pitched signal to reduce noise components.

In a source or a weak electric field in which there are few high-pitched signal components of a voice signal component, a noise signal can be heard significantly.

Signals in bands other than the high pitch are voiced, so the noise component is masked and not felt very much. However, when the signal without high pitch is reproduced as it is, it is easily heard as noise.

Therefore, as described above, the noise signal is removed by varying the voice signal frequency characteristics according to the signal state and the electric field state.

As described in detail above, the present invention has an effect of reproducing a clean voice signal by removing noise components by adjusting the frequency characteristics of the voice signal according to the signal state and the electric field state.

Claims (5)

A signal switching unit which selects and outputs an audio signal or an external audio signal from an external channel signal selected through a tuner, and detects a high sound signal component and a low sound signal component from the audio signal output from the signal switching unit, respectively. Obtains the difference between the signal component detection unit and the high sound signal component and the low sound signal component detected by the signal component detection unit, detects the AGC voltage of the tuner, and determines whether or not the weak electric field is detected. The microcomputer controls the high frequency characteristics and the volume of the signal, and controls the high frequency characteristics of the audio signal output from the signal switching unit under the control of the micro computer when the difference between the signal components is a predetermined value or when the electric field is weak. A low bass / treble control unit for reducing and controlling the bass / treble when there is no difference between the signal components or a weak electric field And a volume control unit for reducing noise by lowering the volume of the voice signal output from the unit. 2. The apparatus of claim 1, wherein the signal component detecting means comprises: a low pass filter for detecting low tone components by low-passing an input voice signal, a first level detector for detecting the amount of low tone components detected above and providing the detected low tone components to a microcomputer; And a second pass detector for detecting a high sound component by high-passing the voice signal, and a second level detector for detecting an amount of the high sound component detected by the voice signal and providing the detected high sound component to a microcomputer. Circuit. Claim 3 has been deleted. Claim 5 has been deleted. A first step of obtaining a level of a high tone signal component and a level of a low tone signal component of a voice signal; and detecting an AGC voltage of a tuner, and then determining the level of the automatic gain control voltage to determine whether a weak electric field is present. Step 2 and, if the level of the high and low signal components is close to '0' or the weak electric field, the third step to reduce the noise by reducing the volume in half, and if the level of the signal component is above a certain value in the first step A fourth step of obtaining a level difference between the high-pitched signal component and the low-tone signal component; and a fifth step of reducing the noise component by lowering the high-frequency frequency characteristic of the voice signal when the level difference of the signal component is a predetermined value or a weak electric field in the fourth step. Voice noise signal removal method characterized in that made.