KR20000047222A - Method and apparatus for repressing reflection by correlation method in satellite communication system - Google Patents

Abstract

PURPOSE: A method and an apparatus for repressing reflection by a correlation method in the satellite communication system are provided to improve the quality of call by detecting a reflection voice signal, inputted to a reflection repression unit, and removing it completely according to a correlation coefficient. CONSTITUTION: A first correlation coefficient generation part(21) outputs a first correlation coefficient(C1) by executing an operation based on a voice signal transmitted to an originating side supplies it to a reflection estimation unit(23). A second correlation coefficient generation part(22) outputs a second correlation coefficient(C2) by executing an operation based on the voice signal transmitted to the originating side supplies it to the reflection estimation unit(23). The reflection estimation unit(23) estimates and outputs reflection based on a voice signal outputted from a voice data storage unit(11), the first correlation coefficient(C1) outputted from the first correlation coefficient generation part(21) and the second correlation coefficient(C2) outputted from the second correlation coefficient generation part(22).

Description

Echo suppression method and apparatus by correlation method in satellite communication system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite communication system. In particular, an echo suppression method using a correlation method in a satellite communication system is capable of improving call quality by detecting an echo sound signal input to an echo suppressor and reliably removing it according to a correlation coefficient. And to an apparatus.

1 is a block diagram showing the configuration of a echo suppressor for a conventional channel modem in a satellite communication system.

In FIG. 1, reference numeral 11 denotes a voice data storage for temporarily storing a voice signal transmitted from a source transmitter. For example, in the case of an echo suppressor implemented with TM320C50DSP, the sampling period of the voice signal is 0.125ms and the echo delay is 48ms. In this case, the stored voice data is 48 / 0.125, which is 384 pieces.

Also, reference numeral 12 is an echo weight that estimates and outputs an echo based on the 384 voice data applied from the voice data storage unit 11 and the recent 384 voice data transmitted from the switching unit 15 to be described later. 13 is an incoming voice detection unit for detecting whether the voice data applied from the voice data storage unit 11 and the voice data transmitted from the receiver side are present, which will be described later when the receiver's voice data is not transmitted. A predetermined signal is applied to the switching unit 15 to be described later.

In addition, reference numeral 14 denotes a counter for counting a specific coefficient based on a predetermined control signal, which is voice data transmitted from the voice data storage 11 and incoming voice transmitted from the synthesizer 16 to be described later. The counting operation is executed based on the detection of the presence or absence of data and is transmitted to the switching 15.

Further, reference numeral 15 denotes a switching unit for transmitting the voice data transmitted from the counter 14 to the echo estimation unit 12 based on the signal transmitted from the incoming voice detection unit 13, which is the incoming voice detection unit. At (13), it is configured to switch to the ON state when the incoming voice is not detected.

Further, reference numeral 16 denotes a synthesizer for synthesizing the signal transmitted from the receiver of the called party and the signal transmitted from the echo estimation unit 12, wherein the voice signal transmitted from the receiver of the called party is combined with the voice signal of the called party. Caller's voice is synthesized and transmitted. Therefore, the synthesizer 16 removes the same voice signal transmitted from the echo estimation unit 12 among the signals transmitted from the receiver of the called party, thereby transmitting only the incoming voice signal from which the echo is removed to the receiver of the calling party. do.

That is, the echo suppressor having the above configuration temporarily stores the voice signal applied from the calling party, estimates the echo, and then removes the echo signal of the calling party synthesized with the voice signal applied from the called party. Therefore, only the called party's voice signal is detected and transmitted to the calling party.

On the other hand, the performance of the echo suppressor is to update the specific coefficient of the counter 14, which turns on the switching unit 15 when the incoming voice detection unit 13 does not detect the incoming voice It is updated by turning ON).

However, the voice signal transmitted from the receiver of the called party is a voice signal transmitted by combining a caller's voice signal (near-end talker) signal with a double talker. The detection was detected by comparing the power level of the input signal, and when the line was unstable and noise was largely input or the echo component was inputted largely, even if there was no input signal of near-end sound, the power level was compared as described above. Since it is detected, the sound is judged to be a near-end sound, and thus both voices may not be detected.

The voice signal transmitted from the receiver of the called party and the voice signal transmitted from the transmitter of the calling party are not shown, but are matched and transmitted through the hybrid device. When an incorrect match is made, an echo is generated. In addition, when the hybrid device operates without an input signal, noise occurs.

Accordingly, the present invention has been made in view of the above-described circumstances. The present invention relates to a correlation method in a satellite communication system which can improve call quality by detecting an echo sound signal input to an echo suppressor and reliably removing it according to a correlation coefficient. It is an object of the present invention to provide an echo suppression method and apparatus.

1 is a block diagram showing the configuration of an echo suppressor for a conventional channel modem in a satellite communication system.

2 is a block diagram showing the configuration of an echo suppression apparatus in a satellite communication system according to a first embodiment of the present invention;

3 is a block diagram showing the configuration of an echo suppression apparatus in a satellite communication system according to a second embodiment of the present invention;

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

11: voice data storage unit 12,23,35: echo estimation unit

13, 34: incoming voice detector 14: counter

15: switching unit 16: synthesis unit

21: first correlation coefficient generator 22: second correlation coefficient generator

31: first gain control signal generator 32: second gain control signal generator

33: gain control signal adjusting unit

In the satellite communication system according to the present invention for realizing the above object, the echo suppression method according to the present invention detects a first voice signal transmitted from the source transmitter to the called party and generates an echo suppression signal based on the received voice signal. In a channel modem of a satellite communication system in which a second voice signal transmitted from a transmitter to a transmitter is synthesized and the echo suppression signal is combined to transmit a third voice signal from which echo is removed, the transmitter is transmitted from the transmitter to the receiver. A voice signal storing step of detecting and storing a first voice signal, A correlation coefficient generating step of generating a first correlation coefficient and a second correlation coefficient based on the second voice signal transmitted from the called party transmitting unit to the calling party, The stored first An echo suppression signal generation step of generating an echo suppression signal based on the first audio signal, the first correlation coefficient, and the second correlation coefficient; A echo canceling step of removing echoes by synthesizing the echo suppression signal with a second speech signal transmitted from the originating party's transmitter to the calling party, and transmitting a third speech signal from which the echo is removed to the calling party; It is characterized by.

The echo canceled third audio signal may be returned to the step of generating a first correlation coefficient, and the generated echo suppression signal may be returned to the step of generating a second correlation coefficient.

In addition, the echo suppression method according to the correlation method in the satellite communication system according to the present invention for realizing the above object detects the first voice signal transmitted from the source transmitter to the called party and generates an echo suppression signal based on the echo signal. In a channel modem of a satellite communication system in which a second voice signal transmitted from a called party transmitting unit to a calling party and the echo suppression signal are synthesized so that a third voice signal from which echo is removed is transmitted to the calling party, from the calling party to the called party. A first voice signal storing step of detecting and storing the first voice signal transmitted, an incoming voice detection step of detecting a second voice signal transmitted from the called party transmitting unit to the calling party, and adjusting the gain of the first voice signal to gain A first gain control signal generation step of generating a control signal, the gain control signal is generated by adjusting the gain of the third audio signal. A second gain control signal generation step, a gain difference control signal generation step of generating a gain difference control signal by comparing the first gain control signal and the second gain control signal, the first sound signal and the second sound signal, and An echo suppression signal generating step of generating an echo suppression signal based on a gain difference control signal, an echo canceling step of canceling an echo by synthesizing the echo suppression signal with a second voice signal transmitted from the called party's transmitter to an originator, And a voice signal transmitting step of transmitting the removed third voice signal to the calling party.

In addition, the echo suppression apparatus according to the correlation method in the satellite communication system according to the present invention for realizing the above object detects the first audio signal transmitted from the source transmitter to the called party, and generates an echo suppression signal based on this; In a channel modem of a satellite communication system in which a second voice signal transmitted from a called party transmitting unit to a calling party and the echo suppression signal are synthesized so that a third voice signal from which echo is removed is transmitted to the calling party, from the calling party to the called party. A voice data storage unit for detecting and storing the first voice signal to be transmitted, and a first correlation coefficient generator for generating a first correlation coefficient by performing calculation based on the second voice signal transmitted from the called party's transmitter to the calling party. A second correlation coefficient generation unit configured to generate a second correlation coefficient by performing an operation based on the second speech signal; An echo estimation unit for estimating and outputting an echo based on a first audio signal output from a book, a first correlation coefficient output from the first correlation coefficient generator, and a second correlation coefficient output from the second correlation coefficient generator; And a synthesizer for synthesizing the second voice signal transmitted from the called party transmitter to the calling party and the signal transmitted from the echo estimation unit and outputting a third voice signal from which echo is removed.

The signal output from the echo estimation unit is applied to the second correlation coefficient generator, and the signal output from the synthesizer is applied to the first correlation coefficient generator.

In addition, the echo suppression apparatus according to the correlation method in the satellite communication system according to the present invention for realizing the above object detects the first audio signal transmitted from the source transmitter to the called party, and generates an echo suppression signal based on this; In a channel modem of a satellite communication system in which a second voice signal transmitted from a called party transmitting unit to a calling party and the echo suppression signal are synthesized so that a third voice signal from which echo is removed is transmitted to the calling party, from the calling party to the called party. A voice data storage for detecting and storing the first voice signal to be transmitted; a first gain control signal generator for generating a gain control signal by adjusting a gain of the first voice signal transmitted from the originating transmitter to the called party; Gain control signal by adjusting the gain of the third speech signal from which the echo is transmitted from the called party's transmitter to the calling party. A second gain control signal generator that generates the first gain control signal applied from the first gain control signal generator and a second gain control signal applied from the second gain control signal generator; A gain control signal adjusting unit for generating a signal, a second voice signal transmitted from the called party transmitting unit to the calling party, a first audio signal applied from the voice data storage unit, and a gain difference control signal applied from the gain control signal adjusting unit; An incoming voice detection unit for detecting an incoming voice, an echo estimation unit for estimating and outputting an echo based on a first voice signal applied from the voice data storage unit and a signal applied from the incoming voice detection unit, and transmitting from the called party transmitting unit to the calling party Synthesizing a second audio signal applied from the echo estimation unit and outputting a third audio signal from which echo is removed And it is characterized in that is configured including a.

That is, according to the present invention having the above-described configuration, in the channel modem of the satellite communication system, the echo quality of the transmitted voice signal can be removed by applying a correlation coefficient, thereby improving call quality.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram showing an echo suppression apparatus based on a correlation method in a satellite communication system according to a first embodiment of the present invention, in which parts corresponding to FIG. 1 are assigned the same reference numerals.

In Fig. 2, reference numeral 21 denotes a first correlation coefficient generation unit that outputs a first correlation coefficient C1 by performing calculation based on the voice signal d (n) transmitted from the called party's transmitter to the calling party. The output is applied to the echo estimation unit 23.

The first correlation coefficient C1 output from the first correlation coefficient generation unit 21 is calculated and output as in Equation 1 below.

In Equation 1 ρd (n) Denotes the short-term average power of the required signal of each adaptive filter, and is calculated as shown in Equation 2 below.

ρd (n) = βρd (n-1) + (1-β) d (n)

Also, in Equation 1 ρu (n) Denotes short-term average power of the error signal of each adaptive filter, and is calculated and calculated as in Equation 3 below.

ρu (n) = βρu (n-1) + (1-β) u (n)

Also, in Equation 1 ρdu (n) Is a cross-correlation value of the required signal and the error signal, and is calculated and calculated as shown in Equation 4 below.

ρdu (n) = βρdu (n-1) + (1-β) d (n) u (n)

Also, the β Has a value between 0 and 1.

That is, the first correlation coefficient generating unit 21 is based on the voice signal d (n) transmitted from the called party transmitting unit to the calling party and the error signal u (n) output from the combining unit 16. After performing the operation through a circular equation, the first correlation coefficient C1 is output.

In FIG. 2, reference numeral 22 denotes a second correlation coefficient generator for outputting a second correlation coefficient C2 by performing calculation based on the voice signal d (n) transmitted from the called party's transmitter to the calling party. The output is applied to the echo estimation unit 23.

In addition, the second correlation coefficient C2 output from the second correlation coefficient generation unit 22 is calculated and output as shown in Equation 5 below.

In Equation 5 ρd (n) Denotes short-term average power of the required signal of each adaptive filter, and is calculated and calculated as in Equation 2 above.

In addition, in Equation 5 Is the short-term average power of the output signal of each adaptive filter, and is calculated as shown in Equation 6 below.

In addition, in Equation 5 Denotes a cross-correlation value of the required signal and the output signal, and is calculated by the following equation (7).

And, β Has a value between 0 and 1.

That is, the second correlation coefficient generation unit 22 outputs the voice signal d (n) transmitted from the called party transmitting unit to the calling party and the output signal outputted from the echo estimation unit 23. The second correlation coefficient C2 is output by performing the operation through the above-described circular equation based on

Further, reference numeral 23 denotes a voice signal output from the voice data storage 11 and the first correlation coefficient C1 and the second correlation coefficient generator 22 output from the first correlation coefficient generator 21. Is an echo estimation unit that estimates and outputs an echo based on the second correlation coefficient C2 output from

Next, the operation of the echo suppression apparatus according to the first embodiment of the present invention having the above-described configuration will be described.

First, a call is established between a calling party and a called party through a channel modem in which the echo suppression device is embedded, and communication is being performed. The first voice signal transmitted from the calling party transmitter to the called party receiver is located on the transmission line. In addition to being linearly extended and stored in the voice data storage unit 11 coupled to the echo estimation unit 12 through the output (out).

On the other hand, the voice signal (d (n) transmitted from the called party to the calling party is a pure voice signal (x (n)) transmitted from the called party part of the voice signal transmitted from the calling party to the called party It is a signal to which the signal r (n) is added.

That is, the voice signal d (n) transmitted from the called party's transmitter to the calling party is applied to the synthesizer 16 and sent to the first correlation coefficient generator 21 and the second correlation coefficient generator 22. To be authorized. In addition, an error signal applied from the echo estimation unit 23 through the synthesis unit 16 ( Is added to the first correlation coefficient generator 21 while the signal u (n) is transmitted to the source receiver.

Accordingly, the first correlation coefficient generation unit 21 is a cyclic type as described above based on the applied audio signal d (n) and the audio signal u (n) applied from the combining unit 16. Next, the first correlation coefficient C1 is output to the echo estimation unit 23.

In addition, the second correlation coefficient generation unit 22 includes the voice signal d (n) applied from the called party transmitting unit and the error signal applied from the reverberation estimating unit 23. The second correlation coefficient C2 is outputted to the echo estimation unit 23 by performing a cyclic equation as described above.

Subsequently, the voice signal from the voice data storage unit 11 and the first correlation coefficient C1 from the first correlation coefficient generator 21 and the second correlation from the second correlation coefficient generator 22 are used. The echo estimation unit 23, which has received the value of the coefficient C2, estimates the echo based on the estimated error signal (2). ) Is applied to the second correlation coefficient generator 22 and the synthesizer 16.

On the other hand, the coefficient update operation of the first correlation coefficient generation unit 21 stops the coefficient update operation when the output first correlation coefficient value is larger than the threshold coefficient Rth, otherwise, it does not exceed the threshold coefficient Rth. If it is small, the operation continues.

In addition, the coefficient update operation of the second correlation coefficient generator 22 continuously executes the coefficient update operation when the output second correlation coefficient C2 is larger than the threshold coefficient Rth. If it is smaller than the coefficient Rth, the operation is stopped.

Therefore, according to the first embodiment, the error signal (i.e., through the first correlation coefficient generation unit 21 and the second correlation coefficient generation unit 22 as described above) By performing the coefficient update operation until the exhaustion of the), the calling party can receive a high quality voice signal without noise.

3 is a block diagram showing a configuration of an echo suppression apparatus according to a second embodiment of the present invention, in which parts that perform the same functions as those of FIG. .

In Fig. 3, reference numeral 31 denotes a first gain control signal generator for adjusting the gain of the voice signal transmitted from the source transmitter to the called party and generating a gain control signal corresponding thereto, and 32 denotes the synthesizer 16. A second gain control signal generator for adjusting the gain of the echo signal transmitted from the called party to the calling party and generating a gain control signal corresponding thereto, wherein 33 is the first gain control signal generator 31 A gain control signal adjusting unit for comparing the first gain control signal applied from the second gain control signal and the second gain control signal applied from the second gain control signal generator 32 to generate the gain difference control signal, and Incoming voice based on the voice signal transmitted from the transmitter to the sender, the voice signal applied from the voice data storage 11, and the gain difference control signal applied from the gain control signal adjuster 33 Detecting and forwarding a voice activity detector for outputting a signal which is the basis to generate the reverberation suppressed signal.

Reference numeral 35 denotes an echo estimation unit for estimating and outputting echo based on the speech signal applied from the speech data storage unit 11 and the signal applied from the incoming speech detector 34.

That is, the echo suppression apparatus according to the second embodiment of the present invention having the above-described configuration has a gain through the first gain control signal generator 31 so that the voice signal transmitted from the transmitter side to the receiver side is appropriate to its transmission sensitivity. The first gain control signal generation section 31 applies the adjusted gain control signal value to the gain control signal adjustment section 33.

In addition, the voice signal transmitted from the called party transmitter to the calling party is transmitted to the calling party receiving the voice signal from which echo is removed through the combining unit 16, and gained through the second gain control signal generator 32. The second gain control signal generation section 32 applies the adjusted gain control signal value to the gain control signal adjustment section 33.

Accordingly, the gain control signal adjusting unit 33 compares the gain control signal value applied from the first gain control signal generation unit 31 with the gain control signal value applied from the second gain control signal generation unit 32. The gain control adjustment value corresponding to the difference is output.

The incoming voice detection unit 34, which has received the gain control adjustment value from the gain control signal adjustment unit 33, is based on the voice signal applied from the voice data storage unit 11 and the voice signal applied from the receiver side transmitting unit. By applying the signal based on the echo estimation to the echo estimation unit 35.

Accordingly, the echo estimation unit 35 outputs the echo suppression signal to the synthesizer based on the signal applied from the voice data storage unit 11 and the signal applied from the incoming voice detector, thereby suppressing echo in the synthesizer. The signal is output to the calling party.

That is, according to the second embodiment, it is possible to realize the echo suppression apparatus which compares the gain control values of the transmitted / received voice signals and removes the echo based on the gain control value according to the difference.

In addition, this invention is not limited to the said Example, It can variously deform and implement within the range which does not deviate from the technical summary of this invention.

As described above, according to the present invention, it is possible to realize a communication service having improved quality by eliminating echo using a correlation coefficient value in a satellite communication system.

Claims (8)

The first voice signal transmitted from the calling party to the called party is detected, and an echo suppression signal is generated based on the second voice signal transmitted from the called party to the calling party, and the echo suppression signal is synthesized. 3 In a channel modem of a satellite communication system in which a voice signal is transmitted to a calling party, A voice signal storing step of detecting and storing a first voice signal transmitted from the calling party transmitting unit to the called party; A correlation coefficient generation step of generating a first correlation coefficient and a second correlation coefficient based on the second voice signal transmitted from the called party transmitting unit to the calling party; An echo suppression signal generation step of generating an echo suppression signal based on the stored first audio signal, a first correlation coefficient, and a second correlation coefficient; An echo cancellation step of removing echoes by synthesizing the echo suppression signal with a second voice signal transmitted from the called party transmitter to the calling party; An echo suppression method according to a correlation method in a satellite communication system, characterized in that it comprises a voice signal transmitting step of transmitting the third audio signal from which echo is removed to the calling party. The method of claim 1, The echo canceled third audio signal returns to the step of generating a first correlation coefficient, and the generated echo suppression signal returns to the step of generating a second correlation coefficient. Method of suppression of echo by the method. The first voice signal transmitted from the calling party to the called party is detected, and an echo suppression signal is generated based on the second voice signal transmitted from the called party to the calling party, and the echo suppression signal is synthesized. 3 In a channel modem of a satellite communication system in which a voice signal is transmitted to a calling party, A first voice signal storing step of detecting and storing a first voice signal transmitted from the calling party transmitter to the called party; An incoming voice detection step of detecting a second voice signal transmitted from the called party transmitting unit to the calling party; Generating a gain control signal by adjusting a gain of the first audio signal; Generating a gain control signal by adjusting a gain of the third audio signal; A gain difference control signal generation step of generating a gain difference control signal by comparing the first gain control signal and a second gain control signal; An echo suppression signal generation step of generating an echo suppression signal based on the first audio signal, the second audio signal, and a gain difference control signal; An echo cancellation step of removing echoes by synthesizing the echo suppression signal with a second voice signal transmitted from the called party transmitter to the calling party; An echo suppression method according to a correlation method in a satellite communication system, characterized in that it comprises a voice signal transmitting step of transmitting the third audio signal from which echo is removed to the calling party. The first voice signal transmitted from the calling party to the called party is detected, and an echo suppression signal is generated based on the second voice signal transmitted from the called party to the calling party, and the echo suppression signal is synthesized. 3 In a channel modem of a satellite communication system in which a voice signal is transmitted to a calling party, A voice data storage unit for detecting and storing a first voice signal transmitted from the calling party transmitter to the called party; A first correlation coefficient generation unit that generates a first correlation coefficient by performing an operation based on a second voice signal transmitted from the called party transmitting unit to the calling party; A second correlation coefficient generator for generating a second correlation coefficient by performing an operation based on the second voice signal; Estimation of echo based on the first audio signal output from the voice data storage unit, the first correlation coefficient output from the first correlation coefficient generator and the second correlation coefficient output from the second correlation coefficient generator Reverberation government, And a synthesizer for synthesizing the second voice signal transmitted from the called party transmitting unit to the calling party and the signal transmitted from the echo estimation unit and outputting a third voice signal from which echo is removed. Echo suppression device by correlation method. The method of claim 4, wherein The coefficient update operation of the first correlation coefficient generating unit stops the coefficient update operation when the output first correlation coefficient value is larger than the threshold coefficient, and continuously executes the operation when the coefficient value is smaller than the threshold coefficient. Echo suppression device by correlation method in satellite communication system. The method of claim 4, wherein The coefficient update operation of the second correlation coefficient generating unit continuously executes the coefficient update operation when the output second correlation coefficient value is larger than the threshold coefficient, and stops the operation when the coefficient coefficient is smaller than the threshold coefficient. Echo suppression apparatus by correlation method in satellite communication system. The method of claim 4, wherein The signal output from the echo estimation unit is applied to the second correlation coefficient generation unit, and the signal output from the synthesis unit is applied to the first correlation coefficient generation unit. Device. The first voice signal transmitted from the calling party to the called party is detected, and an echo suppression signal is generated based on the second voice signal transmitted from the called party to the calling party, and the echo suppression signal is synthesized. 3 In a channel modem of a satellite communication system in which a voice signal is transmitted to a calling party, A voice data storage unit for detecting and storing a first voice signal transmitted from the calling party transmitter to the called party; A first gain control signal generation unit for generating a gain control signal by adjusting a gain of the first audio signal transmitted from the source transmission unit to the destination side; A second gain control signal generator for generating a gain control signal by adjusting the gain of the third audio signal from which the echo is transmitted from the called party transmitting part to the calling party; A gain control signal adjusting unit for comparing the first gain control signal applied from the first gain control signal generator and the second gain control signal applied from the second gain control signal generator to generate a gain difference control signal; An incoming voice detection unit for detecting the incoming voice based on the second voice signal transmitted from the called party transmitting unit to the calling party, the first voice signal applied from the voice data storage unit, and the gain difference control signal applied from the gain control signal adjusting unit; An echo estimation unit for estimating and outputting an echo based on a first audio signal applied from the voice data storage unit and a signal applied from the incoming voice detection unit; And a synthesizer for synthesizing the second voice signal applied from the called party transmitting unit to the calling party and the signal applied from the echo estimation unit and outputting a third voice signal from which echo is removed. Echo suppression device by correlation method.