KR20220077820A - Adaptive gain control apparatus - Google Patents

Abstract

An adaptive gain control apparatus is disclosed.
In this device, the validity determining unit determines whether the input signal from the far end is valid, indicating that the voice signal is present, using the noise signal estimated from the input signal from the far end. The adaptive gain control unit performs adaptive gain control on the input signal from the far end only while the input signal from the far end is valid by the validity determining unit. The validity determining unit compares the noise update unit for estimating the noise signal from the input signal from the far end, and the power of the noise signal estimated by the noise update unit with the power of the input signal from the far end to determine whether the input signal from the far end is valid. and a valid signal determining unit for determining

Description

Adaptive gain control apparatus

The present invention relates to an adaptive gain control device.

In general, full-duplex communication in which the sender and the receiver can communicate in both directions at the same time, such as a telephone line, such as a mobile phone or hands-free in a vehicle, or when one side sends information, the other side must receive all the information to the other side. In half-duplex communication that can send information, the gain control function controls the gain of the signal output to the speaker, or Echo Cancellation/Noise Reduction (EC/NR) for the signal input to the microphone. ) means to control the gain of the performed signal.

The conventional gain control technique performs gain control without considering not only the desired signal but also the echo signal and the noise signal. Therefore, when a residual echo signal that has not been completely removed or a noise signal that has not been suppressed remains in the output signal, the Characteristics can also be amplified together.

As a result, when the level of the output signal is controlled using the conventional gain control function, the SINR gain is not generated because the signal-to-interference-plus-noise ratio (SINR) is the same. There is this.

Accordingly, an object of the present invention is to provide an adaptive gain control apparatus capable of improving signal-to-interference and noise ratios by performing gain adjustment only on effective signals.

The characteristic configuration of the present invention for achieving the object of the present invention as described above and for realizing the characteristic effects of the present invention to be described later is as follows.

According to one aspect of the present invention, there is provided an apparatus for adaptive gain control, the apparatus comprising:

An apparatus for controlling an adaptive gain of a signal transmitted between a near end and a far end in a communication system, using a noise signal estimated from the input signal from the far end to add a voice signal to the input signal from the far end a validity determining unit that determines whether or not the validity indicating that includes wealth.

Here, the validity determining unit includes a noise update unit for estimating a noise signal from the input signal from the far end, and compares the power of the noise signal estimated by the noise update unit with the power of the input signal from the far end, and a valid signal determining unit for determining whether the input signal of

In addition, the effective signal determining unit calculates and compares the low-band power and the high-band power, respectively, when comparing the power of the noise signal and the power of the input signal from the far end.

In addition, when the input signal from the far end is greater than the noise signal in both low band power and high band power, the effective signal determining unit determines that the input signal from the far end is a valid signal.

In addition, when the noise update unit determines that the input signal from the far end is not a valid signal but an invalid signal by the valid signal determination unit, the noise update unit counts the number of times the signal is determined to be an invalid signal, and the number of times to be counted is preset When the update count is exceeded, the noise signal is estimated and updated from the input signal from the far end.

In addition, when the adaptive gain control unit determines that the input signal from the far end is valid by the validity determining unit, counts the number of times determined to be valid, and when the counted number exceeds a preset adjustment count An adaptive gain adjustment is performed on the input signal from the far end.

In addition, when the validity determining unit determines that the input signal from the far end is invalid from the valid state, the adaptive gain adjuster adjusts the adaptive gain for the input signal from the far end for a preset period of time. continuously perform

According to another aspect of the present invention, there is provided an apparatus for adaptive gain control, the apparatus comprising:

An apparatus for controlling an adaptive gain of a signal transmitted between a near-end and a far-end in a communication system, the echo and noise canceling unit outputting an echo and noise-removed signal by performing echo and noise cancellation on an input signal from the far end; A first validity determining unit that determines whether or not validity indicating that a voice signal is present in the input signal from the far end using the first noise signal estimated from the input signal from the far end; When it is determined that the input signal is valid, a second validity determining unit for determining whether the echo and noise-cancelled signal is valid using a second noise signal estimated from the echo and noise-cancelled signal; And and an adaptive gain control unit configured to perform adaptive gain control on the echo and noise cancellation signals only while the echo and noise cancellation signals are determined to be valid by the second validity determining unit.

Here, the second validity determining unit, the determination result by the first validity determining unit indicates that the input signal from the far end is valid, and is used to compare the power of the echo and noise-removed signal and the second noise signal. When the echo and noise-cancelled signal are larger than the second noise signal, it is determined that the echo-cancelled signal is valid.

In addition, the first validity determining unit includes a first noise updater for estimating the first noise signal from the input signal from the far end, and the power of the first noise signal estimated by the first noise updater and the far end. and a first valid signal determining unit for determining whether the input signal from the far end is a valid signal by comparing the power of the input signal of A second noise updater for estimating , the result of the determination of the first valid signal determiner, and the power of the second noise signal estimated by the second noise updater and the power comparison result of the echo and noise-removed signal are used and a second valid signal determining unit that determines whether the echo and noise cancelled signals are valid signals and provides them to the adaptive gain control unit.

According to another aspect of the present invention, there is provided an apparatus for adaptive gain control, the apparatus comprising:

An apparatus for controlling an adaptive gain of a signal transmitted between a near-end and a far-end in a communication system, comprising: an echo and noise canceling unit configured to output an echo and noise-removed signal by performing echo and noise cancellation on an input signal from the near-end; A first validity determining unit that determines whether or not validity indicating that a voice signal is present in the input signal from the far end using the first noise signal estimated from the input signal from the far end; A first adaptive gain adjuster that adaptively adjusts gain on the input signal from the far end only while the input signal from a second validity determining unit for determining whether the input signal of a third validity determining unit that determines whether the echo and noise-cancelled signal are valid by using a noise signal, and the third validity determination unit determines that the echo and noise-cancelled signal are valid only while the signal is valid. and a second adaptive gain adjuster that adaptively adjusts gain on the echo and noise cancelled signals.

Here, the third validity determining unit, the determination result by the second validity determining unit indicates that the input signal from the near-end is valid, and is used to compare the power of the echo and noise-removed signal and the third noise signal. When the echo and noise-cancelled signal are larger than the third noise signal, it is determined that the echo-cancelled signal is valid.

According to the present invention, it is possible to improve the signal-to-interference and noise ratio by performing gain adjustment only on an effective signal.

1 is a diagram illustrating an exemplary apparatus according to the prior art.
2 is a schematic configuration diagram of a full-duplex communication system to which an apparatus for controlling an adaptive gain according to an embodiment of the present invention is applied.
FIG. 3 is a detailed block diagram of the validity determining unit shown in FIG. 2 .
FIG. 4 is an exemplary configuration block diagram of the valid signal determining unit shown in FIG. 3 .
FIG. 5 is a detailed block diagram of the noise updater shown in FIG. 3 .
FIG. 6 is a detailed block diagram of the adaptive gain adjuster shown in FIG. 2 .
7 is a schematic configuration diagram of a full-duplex communication system to which the adaptive gain control apparatus according to the second embodiment of the present invention is applied.
8 is a schematic configuration diagram of a full-duplex communication system to which the adaptive gain control apparatus according to the third embodiment of the present invention is applied.

Hereinafter, with reference to the accompanying drawings, the embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in several different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, throughout the specification, when a part "includes" a certain component, it means that other components may be further included, rather than excluding other components, unless otherwise stated.

First, a conventional gain control technique will be described.

1 is a diagram illustrating an exemplary apparatus according to the prior art.

Referring to FIG. 1 , an input signal inputted from a far end 10 and inputted to a gain adjusting unit 23 that performs gain control of an output of a speaker 21 of a near end 20 is applied. Speaking of Input_A, Input_A may be defined as in Equation 1 below, and its signal to noise ratio (SNR) may be expressed as in Equation 2 below.

[Equation 1]

Here, Singal_A represents a desired signal, and Noise_A represents a noise signal.

[Equation 2]

Here, E[-] represents the ensemble mean, and |A| ² represents the power of signal A.

Meanwhile, in the conventional gain control unit 23, gain control for all signals is performed without distinguishing between a desired signal and an interference/noise signal. Accordingly, the final output Output_A output to the speaker 21 after the gain adjustment is applied to the input signal Input_A by the gain adjuster 23 can be expressed as in Equation 3 below, and the SNR for this can be expressed as It is the same as [Equation 4] of

[Equation 3]

Here, Gain represents a gain adjusted by the gain control unit 23 .

[Equation 4]

As shown in [Equation 4], it can be seen that the SNR of the output signal Output_A and the SNR of the input signal Input_A after the gain adjustment by the gain adjuster 23 are the same. As such, the conventional gain control has no SNR gain as it amplifies both the desired signal and the interference and noise signals.

Meanwhile, the signal Input_M input to the microphone 22 of the near end 20 may be expressed as in Equation 5 below.

[Equation 5]

Here, Signla_A represents a desired signal, Echo_A represents an echo signal, and Noise_A represents a noise signal.

The signal Input_B after EC/NR is applied by the echo canceller 24 and the noise canceller 25 to the signal Input_M input through the microphone 22, respectively, may be expressed as in Equation 6 below. .

[Equation 6]

Here, Echo_A' denotes an echo signal estimated by the echo canceller 24 , and Noise_A' denotes a noise signal estimated by the noise canceller 25 .

In the signal Input_B after EC/NR is applied, if the residual echo signal and the residual noise signal are ResEcho_A and ResNoise_A, respectively, the above [Equation 6] can be expressed as the following [Equation 7], at this time Input_B The SNR can be expressed as [Equation 8] below.

[Equation 7]

[Equation 8]

Thereafter, the output signal Output_B output to the far end 10 after the gain adjustment is applied by the gain adjustment unit 26 to the signal Input_B to which the EC/NR is applied can be expressed as in the following [Equation 9], The SNR for K is as follows [Equation 10].

[Equation 9]

Here, Gain represents a gain adjusted by the gain control unit 26 .

[Equation 10]

As shown in [Equation 10], it can be seen that the SNR of the output signal Output_B and the SNR of the input signal Input_B after the gain adjustment by the gain adjuster 26 are the same. As such, there is a problem in that there is no SNR gain as the conventional gain control for the signal input from the microphone 22 and output to the far end 10 is amplified as well as the desired signal and the interference and noise signals.

Hereinafter, an adaptive gain control apparatus according to an embodiment of the present invention for solving the conventional problems will be described.

2 is a schematic configuration diagram of a full-duplex communication system 1 to which an adaptive gain control apparatus according to an embodiment of the present invention is applied.

As shown in FIG. 2 , the adaptive gain control apparatus 110 according to the embodiment of the present invention is located in the near end 100 of the full-duplex communication system 1 , and is output from the far end 200 to the near end 100 . It determines the validity of the signal to be output through the speaker 120 (hereinafter referred to as 'far-end input signal') and adaptively adjusts the gain for the far-end input signal only while it is determined as a valid signal, that is, a valid signal. carry out At this time, the adaptive gain control device 110 determines the validity of the far-end input signal using the previously estimated noise. If the far-end input signal is determined to be an invalid signal, the adaptive gain control apparatus 110 may update the previous noise with the estimated noise again. can However, rather than performing the noise update immediately when the far-end input signal is determined to be an invalid signal, it is preferable to perform the noise update when the determination as the invalid signal is continuously determined for a predetermined number of times.

Specifically, the adaptive gain control apparatus 110 includes a validity determining unit 111 and an adaptive gain adjusting unit 112 .

The validity determination unit 111 determines the validity of the far-end input signal using the noise signal estimated from the far-end input signal, and transmits the determination result to the adaptive gain adjustment unit 112 . That is, when the far-end input signal is larger than the noise signal and is determined as a valid signal, the validity determination unit 111 activates the determination result signal and transmits it to the adaptive gain adjustment unit 112 . However, when the far-end input signal is determined as an invalid signal because the far-end input signal is not larger than the noise signal, the determination result signal is deactivated and transmitted to the adaptive gain control unit 112 .

An example of a specific configuration of the validity determining unit 111 is shown in FIG. 3 .

As shown in FIG. 3 , the validity determining unit 111 includes a valid signal determining unit 1111 and a noise updating unit 1112 .

The effective signal determining unit 1111 determines the validity of the far-end input signal using the noise signal updated by the noise updater 1112 and transmits it to the noise updater 1112 and the adaptive gain adjuster 112 . . For example, a value obtained by applying a preset weighting constant to the noise signal updated by the noise updater 1112 is compared with the far-end input signal, and when the level of the far-end input signal is greater, it is determined as a valid signal. On the other hand, a value obtained by applying a preset weighting constant to the noise signal updated by the noise updater 1112 is compared with the far-end input signal, and when the level of the far-end input signal is equal to or less than the level of the far-end input signal, it is determined as an invalid signal.

Hereinafter, the valid signal determining unit 1111 will be described in detail with reference to FIG. 4 .

FIG. 4 is an exemplary configuration block diagram of the valid signal determining unit 1111 shown in FIG. 3 .

As shown in FIG. 4 , the effective signal determining unit 1111 includes power spectrum units 11111 and 11112 , low-band power calculators 11113 and 11114 , high-band power calculators 11115 and 11116 , and low-band comparison. It includes a unit 11117 , a high-band comparison unit 11118 , and a determination unit 11119 .

The power spectrum unit 11111 calculates a power spectrum of the far-end input signal, and the power spectrum unit 11112 calculates a power spectrum of the noise signal provided from the noise update unit 1112 .

In the effective signal determining unit 1111 according to the embodiment of the present invention, the method of determining the validity/invalidity of the far-end input signal, that is, the presence/absence of the voice signal using the estimated noise, is performed according to the band of the voice signal and the noise signal. In consideration of the characteristics, it proceeds in a multi-band frequency domain such as a low band and a high band as follows.

For example, the low-band power calculating unit 11113 calculates the low-band power from the power spectrum of the far-end input signal calculated by the power spectrum unit 11111 .

The high-band power calculation unit 11115 calculates high-band power from the power spectrum of the far-end input signal calculated by the power spectrum unit 11111 .

The low-band power calculating unit 11114 calculates low-band power from the power spectrum of the noise signal calculated by the power spectrum unit 11112 .

The high-band power calculation unit 11116 calculates high-band power from the power spectrum of the noise signal calculated by the power spectrum unit 11112 .

)의 곱한 값보다 큰 지의 여부를 비교한다. 이것은 다음의 [수학식 11]과 같이 나타낼 수 있다.The low-band comparator 11117 compares the magnitude of the low-band power of the far-end input signal calculated by the low-band power calculator 11113 with the low-band power of the noise signal calculated by the low-band power calculator 11114 . Specifically, the low-band comparator 11117 determines that the low-band power Input_A _Low of the far-end input signal Input_A calculated by the low-band power calculator 11113 is a noise signal calculated by the low-band power calculator 11114 . ( _{Noise_X} ) The low-band weight constant (

) to determine whether it is greater than the product of This can be expressed as the following [Equation 11].

[Equation 11]

)의 곱한 값보다 큰 지의 여부를 비교한다. 이것은 다음의 [수학식 12]와 같이 나타낼 수 있다.The high-band comparator 11118 compares the high-band power of the far-end input signal calculated by the high-band power calculator 11115 and the high-band power of the noise signal calculated by the high-band power calculator 11116 . Specifically, the high-band comparator 11118 determines that the high-band power (Input_A _High ) of the far-end input signal calculated by the high-band power calculator 11115 is the high-band power of the noise signal calculated by the high-band power calculator 11116 . A preset high-band weighting constant for power (Noise_X _High )

) to determine whether it is greater than the multiplied value of This can be expressed as the following [Equation 12].

[Equation 12]

The determination unit 11119 determines whether the far-end signal is a valid signal using the comparison result of the low-band comparator 11117 and the high-band comparator 11118 to determine whether the far-end signal is valid, and adjusts the noise updater 1112 and the adaptive gain. output to the unit 112 . Specifically, the determination unit 11119 indicates that the comparison result of the low-band comparator 11117 indicates that the low-band power of the far-end input signal is greater than the value obtained by multiplying the low-band power of the noise signal by a preset low-band weighting constant, and It is determined that the far-end signal is a valid signal only when the comparison result of the high-band comparator 11118 indicates that the high-band power of the far-end input signal is greater than a value obtained by multiplying the high-band power of the noise signal by the preset high-band weighting constant. . Accordingly, if the comparison result of the low-band comparator 11117 is less than or equal to the value obtained by multiplying the low-band power of the far-end input signal by the low-band power of the noise signal by a preset low-band weighting constant, or the high-band comparator 11118 ), when the high-band power of the far-end input signal is less than or equal to the value obtained by multiplying the high-band power of the noise signal by a preset high-band weighting constant, it is determined as an invalid signal.

The determination unit 11119 provides the determination result signal to the noise update unit 1112 and the adaptive gain adjustment unit 112. At this time, when the determination result signal is activated, it indicates that the far-end signal is a valid signal, and the determination result When the signal is deactivated, it indicates that the far-end signal is an invalid signal. Here, that the far-end signal is a valid signal indicates that the far-end 200 speaker's voice signal is present, and that the far-end signal is an invalid signal means that the far-end 200 speaker's voice signal is absent.

Next, the noise updater 1112 estimates the noise signal from the far-end input signal and provides it to the effective signal determiner 1111 . At this time, the noise update unit 1112 counts the number of times the far-end input signal is determined to be an invalid signal by the valid signal determination unit 1111, and when the counting number exceeds a predetermined number, the far-end input signal is continuously valid It is determined that it is a signal that has not been updated and the noise signal is updated.

Hereinafter, the noise updater 1112 will be described in detail with reference to FIG. 5 .

FIG. 5 is a detailed block diagram of the noise updater 1112 shown in FIG. 3 .

As shown in FIG. 5 , the noise updater 1112 includes a noise estimator 11121 and an updater 11122 .

In general, since the level or characteristics of a noise signal for a microphone input can be continuously changed in real time, it is necessary to continuously track and update the estimated noise.

The noise estimator 11121 estimates a noise signal included in the far-end input signal by using the far-end input signal. The noise estimator 11121 uses the method disclosed in Boll.S.F's 'Suppression of acoustic noise in speech using spectral subtraction' (IEEE Transactions on Signal Processing, 1979, Vol. to estimate According to this method, when the noise signal mixed with the far-end input signal is d[n], the noise estimator 11121 can estimate the noise for Noise_X and Noise_Y as shown in Equation 13 below.

[Equation 13]

Whenever an update signal is received from the updater 11122 , the noise estimator 11121 estimates a noise signal for the far-end input signal and provides it to the effective signal determiner 1111 .

When the determination result signal received from the valid signal determination unit 1111 indicates that the signal is an invalid signal, the update unit 11122 continuously counts the number of times indicating that the signal is an invalid signal, and the counting number exceeds a preset update count. An update signal is output to the noise estimator 11121 to perform noise estimation again from the corresponding section by determining that it has changed.

Next, the adaptive gain adjusting unit 112 adaptively adjusts the gain on the far-end input signal only while the validity determining unit 111 indicates that the far-end input signal is a valid signal.

Hereinafter, the adaptive gain adjuster 112 will be described in detail with reference to FIG. 6 .

6 is a detailed block diagram of the adaptive gain adjustment unit 112 shown in FIG.

As shown in FIG. 6 , the adaptive gain adjuster 112 includes a gain adjuster 1121 and an adaptive adjuster 1122 .

The gain control unit 1121 performs gain control on the far-end input signal output from the far-end 200 , but only performs gain control when the gain control signal is received from the adaptive control unit 1121 . Here, since the gain control operation for the far-end input signal is the same as the gain control operation according to the prior art, a detailed description thereof will be omitted.

When the determination result signal output from the validity determination unit 111 indicates that the signal is a valid signal, the adaptive adjustment unit 1122 counts the number of times indicating that the signal is a valid signal, and when the counting number exceeds a preset adjustment count, the gain adjustment signal It is output to the gain adjustment performing unit 1122 . Counting the effective signal as described above to prevent a problem that can be applied to an unwanted signal when the gain is adjusted, for example, amplified, on the far-end input signal immediately when the effective signal is determined without counting the effective signal in various noise environments This is done.

In addition, in the case of a voice signal, it may be difficult to determine an effective signal for a corresponding section because the signal level at the end of the utterance is lowered depending on the strength of pronunciation or intonation. Therefore, even if the validity determining unit 111 determines that the far-end input signal is no longer valid during the process of performing gain adjustment on the far-end input signal, gain adjustment can be continuously performed on the far-end input signal for a certain period of time. A guard zone is required.

Accordingly, when the adaptive control unit 1122 indicates that the determination result signal received from the validity determination unit 111 is a valid signal, but indicates that it is not a valid signal, that is, when it indicates that it is an invalid signal, a predetermined time is set in advance from that time. The gain control unit 1121 outputs a gain control signal that allows the gain control unit 1121 to continuously perform gain control on the far-end input signal until the time elapses.

As described above, according to the adaptive gain control apparatus 110 according to the embodiment of the present invention, when the far-end input signal input to the adaptive gain control unit 112 is defined as in [Equation 1], the adaptive The output signal Output_A after the gain adjustment is adaptively performed by the type gain control unit 112 may be expressed as in [Equation 14], and the SNR thereof is as follows [Equation 15].

[Equation 14]

Here, Gain represents a gain adjusted by the adaptive gain control unit 112 .

[Equation 15]

As shown in [Equation 15], it can be seen that the SNR of the output signal Output_A and the SNR of the input signal Input_A after the gain is adjusted by the adaptive gain adjuster 112 are different from each other. Specifically, it can be seen that the SNR of the input signal Input_A increases by the ensemble average of the squares of the gain adjusted by the adaptive gain adjuster 112 . This is because the adaptive gain control apparatus 110 according to the embodiment of the present invention gain control only the level of the desired signal that is an effective signal in consideration of the characteristics of the interference and noise signal, so that the SNR gain equal to the level of the adjusted gain in the output signal is obtained. because it occurs

As such, according to an embodiment of the present invention, by performing gain control only on a desired signal, the signal-to-interference and noise ratio can be improved.

Meanwhile, in the above, the adaptive gain control for the far-end input signal input from the far-end 200 and output to the speaker 120 of the near-end 100 has been described, but the technical scope of the present invention is not limited thereto. , can be applied to other configurations as well.

Hereinafter, an adaptive gain control apparatus according to a second embodiment of the present invention will be described. The adaptive gain control apparatus according to the second embodiment of the present invention corresponds to an apparatus for performing gain adjustment after echo and noise cancellation on a far-end input signal input from the far-end 200 .

7 is a schematic configuration diagram of a full-duplex communication system 2 to which the adaptive gain control apparatus according to the second embodiment of the present invention is applied. For convenience of description, components performing the same functions as in FIGS. 2 to 6 described above in FIG. 7 will be described using the same reference numerals.

7, the adaptive gain control apparatus 300 according to the second embodiment of the present invention is located in the near end 100 of the full-duplex communication system 2, and is outputted from the far end 200 to perform echo and The validity of the far-end input signal input to the noise canceling unit 310 is determined and the validity of the echo and noise-removed signals are determined by the echo and noise canceling unit 310, and only while both are determined to have validity, the echo and The gain adjustment is adaptively performed on the noise-removed signal. Similarly, the adaptive gain control apparatus 300 determines the validity of the far-end input signal and the echo and noise-removed signal using the previously estimated noise, and if the far-end input signal and the echo and noise-removed signal are invalid signals If it is determined, the previous noise can be updated with the re-estimated noise. However, rather than performing the noise update immediately when the far-end input signal and the echo and noise-removed signal are determined to be invalid signals, it is preferable to perform the noise update when the invalid signal is continuously determined for a certain number of times.

Specifically, the adaptive gain control apparatus 300 includes a first validity determining unit 320 , a second validity determining unit 330 , and an adaptive gain adjusting unit 340 .

The first validity determination unit 320 determines the validity of the far-end input signal using the noise signal estimated from the far-end input signal, and transmits the determination result to the second validity determination unit 330 . That is, when the far-end input signal is larger than the noise signal and is determined as a valid signal, the first validity determining unit 320 activates the determination result signal and transmits it to the second validity determining unit 330 . However, when the far-end input signal is determined as an invalid signal because the far-end input signal is not larger than the noise signal, the determination result signal is deactivated and transmitted to the second validity determination unit 330 .

Specifically, the first validity determining unit 320 includes a first valid signal determining unit 321 and a first noise updating unit 322 .

The first valid signal determining unit 321 determines the validity of the far-end input signal by using the noise signal updated by the first noise updater 322, and uses the result of the determination to the second validity determining unit 330 and the second valid signal. 1 It is transmitted to the noise updater 322 . For example, the first valid signal determining unit 321 compares the far-end input signal with a value obtained by applying a preset weighting constant to the noise signal updated by the first noise updater 322, so that the level of the far-end input signal is higher. In a large case, it is determined as a valid signal. On the other hand, a value obtained by applying a preset weighting constant to the noise signal updated by the first noise updater 322 is compared with the far-end input signal, and when the level of the far-end input signal is equal to or less than the level of the far-end input signal, it is determined as an invalid signal.

As such, except for the configuration for transferring the determination result to the second validity determining unit 330, the operating principle of the first valid signal determining unit 321 is the effective signal determining unit ( 1111), so a detailed description will be omitted here.

The first noise updater 322 estimates a noise signal from the far-end input signal and provides it to the first valid signal determiner 321 . At this time, the first noise update unit 322 counts the number of times the far-end input signal is determined to be an invalid signal by the first valid signal determination unit 321, and when the counting number exceeds a certain number of times, the far-end input signal It is determined that is a signal that is not valid continuously, and the update is performed on the noise signal.

The first noise updater 322 is also the same as the noise updater 1112 described above with reference to FIGS. 2 to 5 , and thus a detailed description thereof will be omitted.

Next, when the validity of the far-end input signal is determined by the first validity determining unit 320 , the second validity determining unit 330 performs echo and noise cancellation by using a noise signal estimated from the echo and noise removed signal. The validity of the signal is determined and the determination result is transmitted to the adaptive gain control unit 340 . That is, the second validity determination unit 330 first determines the validity of the echo and noise-removed signal only when the validity of the far-end input signal is determined by the first validity determination unit 320 . At this time, if the echo and noise-removed signal is larger than the noise signal and is determined as an effective signal, the signal is activated and transmitted to the adaptive gain control unit 340 . However, if the echo and noise-removed signal is not greater than the noise signal and thus is determined as an invalid signal, the determination result signal is inactivated and transferred to the adaptive gain control unit 340 .

Specifically, the second validity determining unit 330 includes a second valid signal determining unit 331 and a second noise updating unit 332 .

The second valid signal determination unit 331 uses the determination result signal transmitted from the first validity determination unit 320 and the noise signal updated by the second noise update unit 332 to provide echo and noise-removed signals. The validity is determined, and the determination result is transmitted to the adaptive gain adjuster 340 and the second noise updater 332 . For example, when it is determined that the far-end input signal is not a valid signal by the determination result signal transmitted from the first validity determination unit 320 , the second valid signal determining unit 331 may determine the echo and noise-removed signal. It is immediately determined that the determination result is an invalid signal without validity determination. However, when it is determined that the far-end input signal is a valid signal by the determination result signal transmitted from the first validity determination unit 320, the second valid signal determining unit 331 sends the second noise updater 332 By comparing the value to which a preset weighting constant is applied to the noise signal updated by the controller and the signal from which the echo and noise have been removed, it is determined as a valid signal when the level of the signal from which the echo and noise has been removed is greater. On the other hand, the value obtained by applying a preset weighting constant to the noise signal updated by the second noise updater 332 is compared with the echo and noise-removed signals, and is invalid when the levels of the echo and noise-removed signals are less than or equal to the value. identified as a signal.

As such, only when the result determined by the first validity determining unit 320 is a valid signal, the second valid signal determining unit 331 determines the validity of the echo and noise-removed signal, except for the configuration of the second valid signal. Since the operating principle of the signal determining unit 331 is the same as that of the effective signal determining unit 1111 described with reference to FIGS. 2 to 5 , a detailed description thereof will be omitted herein.

The second noise updater 332 estimates a noise signal from the echo and noise-removed signal and provides it to the second valid signal determiner 331 . In addition, the second noise update unit 332 counts the number of times determined to be an invalid signal by the second valid signal determination unit 331, and when the counting number exceeds a certain number of times, the echo and noise-removed signal are continuously to determine that it is an invalid signal and proceed with the update of the noise signal.

The second noise updater 332 is also the same as the noise updater 1112 described above with reference to FIGS. 2 to 5 , and thus a detailed description thereof will be omitted.

The adaptive gain adjuster 340 adaptively adjusts the gain of the echo and noise-cancelled signal only while indicating that the far-end input signal and the echo and noise-cancelled signal are valid signals from the second validity determining unit 330 . carry out

Since the operating principle of the adaptive gain adjuster 340 is the same as that of the adaptive gain adjuster 112 described with reference to FIGS. 2 to 6 described above, a detailed description thereof will be omitted herein.

As described above, according to the second embodiment of the present invention, an effective signal is determined using both signals before and after the echo and noise cancellation by the echo and noise cancellation unit 310, and gain adjustment is adaptively performed, By improving the reliability of effective signal and noise discrimination, adaptive gain adjustment can be performed.

Meanwhile, in the above, only the gain control in the flow of outputting the far-end input signal received from the far-end 200 to the speaker 120 has been described, but the technical scope of the present invention is not limited thereto, and the microphone of the near-end 100 It can also be applied to the gain adjustment of the flow of outputting the voice signal input through 130 to the far end 200 .

Hereinafter, an adaptive gain control apparatus according to a third embodiment of the present invention will be described. The adaptive gain control apparatus according to the third embodiment of the present invention is the same as the adaptive gain control apparatus 110 according to the first embodiment of the present invention described with reference to FIGS. 2 to 6, from the far end 200 to the near-end. Similar to the adaptive gain control for the far-end input signal input as 100 and the adaptive gain control apparatus 300 according to the second embodiment of the present invention described with reference to FIG. 7 , the near-end 200 to the microphone 130 ) corresponds to a configuration including both adaptive gain control when a signal before and after echo and noise cancellation is performed on a near-end input signal input through ) is an effective signal.

8 is a schematic configuration diagram of a full-duplex communication system 3 to which the adaptive gain control apparatus according to the third embodiment of the present invention is applied.

As shown in FIG. 8 , the adaptive gain control device 400 according to the third embodiment of the present invention is located in the near end 100 of the full-duplex communication system 3, and is outputted from the far end 200 to the near end ( 100) determines the validity of the far-end input signal to be output through the speaker 120 and adaptively performs gain adjustment on the far-end input signal only while it has validity, that is, while it is determined as a valid signal, and also 200) to determine the validity of the near-end input signal input through the microphone 130 and input to the echo and noise canceling unit 430, and at the same time determine the validity of the echo and noise canceling signal by the echo and noise canceling unit 430 Gain adjustment is adaptively performed on the echo and noise-cancelled signals only while it is determined that all of them are valid.

Similarly, the adaptive gain control apparatus 400 determines the validity of the far-end input signal, the near-end input signal, and the echo and noise-removed signals using the previously estimated noise, respectively, and if the far-end input signal, the near-end input signal and the echo and when it is determined that the noise-removed signal is an invalid signal, the previous noise may be updated with the re-estimated noise. However, rather than performing the noise update immediately when the far-end input signal, the near-end input signal, and the echo and noise-removed signal are determined to be invalid signals, the noise update is performed when the judgment as an invalid signal is continuously determined for a certain number of times. it is preferable

Specifically, the adaptive gain control apparatus 400 includes a third validity determination unit 410 , a first adaptive gain adjustment unit 420 , a fourth validity determination unit 440 , a fifth validity determination unit 450 and and a second adaptive gain adjuster 460 .

First, the third validity determining unit 410 and the first adaptive gain adjusting unit 420 of the adaptive gain control apparatus 400 determine the effectiveness of the adaptive gain control apparatus 110 according to the embodiment of the present invention described above. Since the operation principle of the determining unit 111 and the adaptive gain adjusting unit 112 is the same, reference is made to the description according to the embodiment of the present invention described with reference to FIGS. 1 to 6 .

In addition, the fourth validity determining unit 440 , the fifth validity determining unit 450 , and the second adaptive gain adjusting unit 460 of the adaptive gain control apparatus 400 are configured according to the above-described second embodiment of the present invention. Since the operation principle is the same as that of the first validity determining unit 320, the second validity determining unit 330, and the adaptive gain adjusting unit 340, refer to the description of the second embodiment of the present invention described with reference to FIG. do.

In addition to the above-described embodiments, it will be readily understood by those skilled in the art that more various forms of implementation are possible using the concept of performing gain adjustment on an input signal only while the input signal is a valid signal, which is a feature of the present invention.

The embodiment of the present invention described above is not implemented only through the apparatus and method, and may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium in which the program is recorded.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto. is within the scope of the right.

Claims (12)

An adaptive gain control device for a signal transmitted between a near end and a far end in a communication system, comprising:
a validity determining unit that determines whether the input signal from the far end is valid using the noise signal estimated from the input signal from the far end to determine whether a voice signal is present; and
An adaptive gain adjusting unit that adaptively adjusts gain on the input signal from the far end only while the input signal from the far end is valid by the validity determining unit
An adaptive gain control device comprising a. According to claim 1,
The validity determination unit,
a noise updater for estimating a noise signal from the input signal from the far end; and
A valid signal determining unit for determining whether the input signal from the far end is a valid signal by comparing the power of the noise signal estimated by the noise updater with the power of the input signal from the far end
Including, adaptive gain control device. 3. The method of claim 2,
The valid signal determining unit,
When comparing the power of the noise signal and the power of the input signal from the far end, calculating and comparing low-band power and high-band power, respectively,
Adaptive gain control unit. 4. The method of claim 3,
The effective signal determining unit determines that the input signal from the far end is a valid signal when the input signal from the far end is greater than the noise signal in both low-band power and high-band power,
Adaptive gain control unit. 3. The method of claim 2,
When the noise update unit determines that the input signal from the far end is not a valid signal but an invalid signal by the valid signal determining unit, the noise update unit counts the number of times the signal is determined to be the invalid signal, and the counted number of times is a preset update count estimating and updating the noise signal from the input signal from the far end when
Adaptive gain control unit. According to claim 1,
The adaptive gain control unit counts the number of times the input signal from the far end is determined to be valid by the validity determination unit as valid, and when the counted number exceeds a preset adjustment count, the far end performing adaptive gain adjustment on the input signal from
Adaptive gain control unit. According to claim 1,
The adaptive gain adjusting unit continuously adjusts the adaptive gain for the input signal from the far end for a preset period of time when the validity determining unit determines that the input signal from the far end is in an invalid state. performed with
Adaptive gain control unit. An adaptive gain control device for a signal transmitted between a near-end and a far-end in a communication system, comprising:
an echo and noise canceling unit that performs echo and noise cancellation on the input signal from the far end to output a signal from which the echo and noise are removed;
a first validity determining unit that determines whether the input signal from the far end is valid using a first noise signal estimated from the input signal from the far end to determine whether a voice signal is present;
When it is determined by the first validity determining unit that the input signal from the far end is valid, whether the echo and noise cancelled signal is valid using the second noise signal estimated from the echo and noise cancelled signal A second validity determination unit to determine, and
An adaptive gain adjustment unit that performs adaptive gain adjustment on the echo and noise cancellation signal only while it is determined that the echo and noise cancellation signal are valid by the second validity determination unit
An adaptive gain control device comprising a. 9. The method of claim 8,
The second validity determining unit,
The result of determination by the first validity determining unit indicates that the input signal from the far end is valid, and the echo and noise-removed signal is obtained by comparing the power of the echo- and noise-removed signal and the second noise signal. determining that the echo and denoised signal is valid when it is greater than the second noise signal;
Adaptive gain control unit. 9. The method of claim 8,
The first validity determination unit,
a first noise updater for estimating the first noise signal from the input signal from the far end; and
A first valid signal determining unit for determining whether the input signal from the far end is a valid signal by comparing the power of the first noise signal estimated by the first noise updater with the power of the input signal from the far end
including,
The second validity determining unit,
a second noise updater for estimating the second noise signal from the echo and noise cancelled signals; and
The validity of the echo and noise-cancelled signal is determined using the result of the determination of the first valid signal determining unit, the power of the second noise signal estimated by the second noise updater, and the power comparison result of the echo and noise-cancelled signal. A second valid signal determining unit that determines whether a signal is present and provides it to the adaptive gain adjuster
Including, adaptive gain control device. An adaptive gain control device for a signal transmitted between a near-end and a far-end in a communication system, comprising:
an echo and noise canceling unit that performs echo and noise cancellation on the input signal from the near end to output an echo and noise cancelled signal;
a first validity determining unit that determines whether the input signal from the far end is valid using a first noise signal estimated from the input signal from the far end to determine whether a voice signal is present;
a first adaptive gain adjusting unit that adaptively adjusts gain on the input signal from the far end only while the input signal from the far end is valid by the first validity determining unit;
a second validity determining unit for determining whether the input signal from the near end is valid using a second noise signal estimated from the input signal from the near end;
When it is determined by the second validity determining unit that the input signal from the near-end is valid, whether the echo and noise-cancelled signal is valid using a third noise signal estimated from the echo- and noise-cancelled signal A third validity determination unit to determine, and
A second adaptive gain adjustment unit that performs adaptive gain adjustment on the echo and noise cancellation signal only while it is determined by the third validity determination unit that the echo and noise cancellation signal are valid
An adaptive gain control device comprising a. 12. The method of claim 11,
The third validity determination unit,
A result of the determination by the second validity determining unit indicates that the input signal from the near end is valid, and the echo and noise-removed signal is obtained by comparing the power of the echo- and noise-removed signal and the third noise signal. determining that the echo and denoised signal is valid when it is greater than the third noise signal;
Adaptive gain control unit.

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