【０００１】[0001]
【発明の属する技術分野】本発明は、長距離通信回線や
拡声電話機等において通話品質の劣化要因となるエコー
信号を消去するためのエコーキャンセラにおいて、ダブ
ルトーク（双方向同時通話）時の処理を行なうエコーキ
ャンセラのダブルトーク検出制御装置および検出制御方
法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an echo canceller for canceling an echo signal which is a cause of deterioration of speech quality in a long-distance communication line, a loudspeaker, and the like. The present invention relates to a double talk detection control device and a detection control method for an echo canceller that performs echo cancellation.
【０００２】[0002]
【従来の技術】拡声電話機に使われる、ダブルトーク検
出器を備えたエコーキャンセラの一般的な構成を図２に
示す。図２において、遠端から送られてきたアナログ信
号は端子１３を通り、Ａ／Ｄ変換器９でディジタル信号
に変換された受信信号ｘ（ｎ）はＤ／Ａ変換器４でアナ
ログ信号に変換され、端子１１を通りスピーカ２から出
力され、マイク１までのエコー経路Ｈを通ってエコーと
なり、このエコーが近端話者音声Ｎｉｎに加わった信号
がマイク１に入力され、端子１０を通りＡ／Ｄ変換器３
でディジタル信号に変換される。変換された送信信号ｙ
（ｎ）は、受信信号ｘ（ｎ）を入力とする適応ディジタ
ルフィルタ６から出力された、擬似エコー信号ｚ（ｎ）
を減算器５で差し引かれて残差信号ｅ（ｎ）として出力
される。残差信号ｅ（ｎ）はＤ／Ａ変換器８でアナログ
信号に変換され、端子１２を通り遠端に送られる。ここ
で、インデックスｎは離散信号の時刻を表わす。図２の
ような構成のエコーキャンセラの適応動作において、近
端話者の音声はフィルタの適応を乱すので、近端話者音
声Ｎｉｎの存在を検出して適応動作を停止する必要があ
る。そこで、ダブルトーク検出器７は受信信号ｘ
（ｎ）、送信信号ｙ（ｎ）、残差信号ｅ（ｎ）の信号を
受けてダブルトークの状態を検出し、適応ディジタルフ
ィルタ６に対して適応動作の禁止、解除の信号を送出
し、制御する。具体的には、受信信号ｘ（ｎ）と送信信
号ｙ（ｎ）のレベルを観測し、その差から近端話者音声
Ｎｉｎの検出を行なう方法や、受信信号ｘ（ｎ）とエコ
ーキャンセラで消去を行なった後の残差信号ｅ（ｎ）の
レベルを観測し、近端話者の音声により適応が乱された
結果、残差信号ｅ（ｎ）が増大することから近端話者音
声Ｎｉｎの検出を行なう方法等がとられる。後者の方法
の例として、図４に示すような構成のダブルトーク検出
器を用いる、特開昭６３−２３８７２７号公報の技術が
ある。この発明は、近端話者音声の検出を行なう判定し
きい値を、その過去の値、受信信号および残差信号のパ
ワーを積分処理した値を使って更新することを特徴とし
ている。2. Description of the Related Art FIG. 2 shows a general configuration of an echo canceller having a double talk detector used in a loudspeaker. In FIG. 2, an analog signal sent from the far end passes through a terminal 13, and a received signal x (n) converted to a digital signal by an A / D converter 9 is converted to an analog signal by a D / A converter 4. Then, the signal is output from the speaker 2 through the terminal 11, passes through an echo path H to the microphone 1, and becomes an echo. / D converter 3
Is converted into a digital signal. Converted transmission signal y
(N) is a pseudo echo signal z (n) output from the adaptive digital filter 6 which receives the received signal x (n).
Is subtracted by the subtractor 5 and is output as a residual signal e (n). The residual signal e (n) is converted to an analog signal by the D / A converter 8 and sent to the far end through the terminal 12. Here, the index n represents the time of the discrete signal. In the adaptive operation of the echo canceller configured as shown in FIG. 2, since the voice of the near-end speaker disturbs the adaptation of the filter, it is necessary to stop the adaptive operation by detecting the presence of the near-end speaker voice Nin. Therefore, the double talk detector 7 receives the received signal x
(N), the signal of the transmission signal y (n) and the signal of the residual signal e (n) are received, the state of the double talk is detected, and a signal for prohibiting or releasing the adaptive operation is sent to the adaptive digital filter 6. Control. Specifically, the level of the received signal x (n) and the level of the transmitted signal y (n) are observed, and the near-end talker's voice Nin is detected based on the difference between the levels, or the received signal x (n) and the echo canceller are used. The level of the residual signal e (n) after the erasure is observed, and the adaptation is disturbed by the voice of the near-end speaker. As a result, the residual signal e (n) increases. A method of detecting Nin is used. As an example of the latter method, there is a technique disclosed in Japanese Patent Application Laid-Open No. 63-238727, which uses a double talk detector having a configuration as shown in FIG. The present invention is characterized in that the determination threshold value for detecting the near-end speaker's voice is updated using its past value and a value obtained by integrating the power of the received signal and the residual signal.
【０００３】以下に図４を用いて発明の概要を具体的に
説明する。受信信号ｘ（ｎ）、送信信号ｙ（ｎ）、残差
信号ｅ（ｎ）は、パワー検出器２３、２４、２５でそれ
ぞれ信号のパワーに変換され、そのうち受信信号と残差
信号のパワーＰｘ（ｎ）、Ｐｅ（ｎ）を用いてパワー比
算出手段２６でパワー比Ｒｘ＿ｅ（ｎ）が算出される。
一方、受信信号のパワーＰｘ（ｎ）が比較器２８でしき
い値ＸＴＨと比較され、受信信号の有音／無音の判定結
果が出力される。受信信号が無音の時、適応禁止信号発
生部３５は適応禁止の信号を出力し、３１のしきい値設
定手段Ａはダブルトーク検出のしきい値であるＴＨ１
（ｎ）の値を保存する。受信信号が有音の時、送信信号
のパワーＰｙ（ｎ）は比較器３４でしきい値ＹＴＨと比
較され、送信信号の有音／無音の判定結果が出力され
る。送信信号が無音の時、適応禁止信号発生部３５が適
応禁止を解除すると共に、３１のしきい値設定手段Ａは
しきい値ＴＨ１（ｎ）を急速に減少させる。送信信号が
有音の時、３１のしきい値設定手段Ａは、前記パワー比
Ｒｘ＿ｅ（ｎ）と、そのパワー比にマージン付加手段２
９でマージンＭＧＮ１を付加された値ｘ＿ｅ＿ｍ（ｎ）
を受けて、それらの値とその過去の値を積分処理するこ
とによってしきい値ＴＨ１（ｎ）を設定する。さらに、
前記ｘ＿ｅ＿ｍ（ｎ）の値と、設定されたしきい値ＴＨ
１（ｎ）が比較器３３で比較され、ダブルトーク状態か
どうかを判定する。前者が後者より小さいとき、ダブル
トーク状態と判定され、適応禁止信号発生部３５は適応
禁止の信号を出力し、逆に前者が後者より大きいとき適
応禁止を解除する。このような構成とすることにより、
ダブルトークの検出感度は高くなり、それでいてダブル
トーク状態の判定は、エコー経路の微少変動の影響を受
けにくくなっている。また、受信信号が有音（遠端話者
音声が存在）と判定され、かつエコー信号すなわち送信
信号が無音と判定された場合、前記しきい値を急速に減
少させ、早期に適応動作を再開することにより、必要以
上に適応動作の停止が生ずるのを防いでいる。[0003] The outline of the present invention will be specifically described below with reference to FIG. The received signal x (n), the transmitted signal y (n), and the residual signal e (n) are converted into signal powers by power detectors 23, 24, and 25, respectively. (N), the power ratio Rx_e (n) is calculated by the power ratio calculating means 26 using Pe (n).
On the other hand, the power Px (n) of the received signal is compared with the threshold value XTH by the comparator 28, and a sound / non-sound determination result of the received signal is output. When the received signal is silent, the adaptation prohibition signal generator 35 outputs an adaptation prohibition signal, and the threshold setting means A of 31 sets a threshold TH1 for detecting double talk.
Save the value of (n). When the reception signal is sound, the power Py (n) of the transmission signal is compared with the threshold value YTH by the comparator 34, and the result of the sound / non-sound determination of the transmission signal is output. When the transmission signal is silent, the adaptation prohibition signal generator 35 cancels the adaptation prohibition, and the threshold setting means A of 31 rapidly reduces the threshold TH1 (n). When the transmission signal is a sound, the threshold setting means A of 31 sets the power ratio Rx_e (n) and the power ratio to the margin adding means 2
9, the value x_e_m (n) to which the margin MGN1 is added
Then, the threshold value TH1 (n) is set by integrating these values and their past values. further,
X_e_m (n) value and a set threshold value TH
1 (n) is compared by the comparator 33 to determine whether or not it is in the double talk state. When the former is smaller than the latter, the double talk state is determined, and the adaptation prohibition signal generator 35 outputs an adaptation prohibition signal. Conversely, when the former is larger than the latter, the adaptation prohibition is canceled. With such a configuration,
The detection sensitivity of the double talk is increased, and the determination of the double talk state is less likely to be affected by minute fluctuations in the echo path. When it is determined that the received signal is voiced (the presence of the far-end speaker's voice) and the echo signal, that is, the transmitted signal is determined to be silent, the threshold value is rapidly reduced and the adaptive operation is restarted early. This prevents the adaptation operation from stopping more than necessary.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記従
来例では、送信信号の有音・無音の判定は信号のレベル
と固定のしきい値との比較で行なっていたため、エコー
経路の特性によってエコー信号のレベルが大きく変化し
ている状況では有音・無音の判定を誤る場合があり、適
応動作の制御が適切に行なわれないという問題があっ
た。However, in the above-mentioned conventional example, the determination of the presence or absence of sound in the transmission signal is made by comparing the signal level with a fixed threshold value. In a situation where the level of the sound is greatly changed, there is a case where the determination of the presence or absence of sound may be erroneous, and there is a problem that the control of the adaptive operation is not properly performed.
【０００５】[0005]
【課題を解決するための手段】上記課題を解決するため
に、本発明は、受信信号と送信信号のパワーに関連する
値の比から送信信号の有音無音判定用しきい値を設定す
る手段と、送信信号のパワーに関連する値の代わりに、
受信信号と送信信号のパワーに関連する値の比にマージ
ンを付加した値と、設定された送信信号の有音無音判定
用しきい値から送信信号の有音無音判定を行なう手段と
を備える。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a means for setting a threshold for determining the presence or absence of sound or silence of a transmission signal from a ratio of a value related to the power of the reception signal and the power of the transmission signal. And a value related to the power of the transmitted signal,
Means for performing a sound / silence determination of the transmission signal from a value obtained by adding a margin to a ratio of a value relating to the power of the reception signal and the power of the transmission signal and a set threshold for voice / silence determination of the transmission signal.
【０００６】前記手段を用い、本発明ではエコーキャン
セラの動作時に、ダブルトーク検出しきい値に基づきダ
ブルトーク状態を検出し、前記適応ディジタルフィルタ
の適応動作を禁止するエコーキャンセラのダブルトーク
検出装置および検出方法において、次のような手順によ
りダブルトーク検出しきい値を制御するようにした。Using the above means, the present invention provides a double talk detecting apparatus for an echo canceller which detects a double talk state based on a double talk detection threshold value during operation of the echo canceller, and inhibits the adaptive operation of the adaptive digital filter. In the detection method, the double talk detection threshold is controlled by the following procedure.
【０００７】すなわち、前記受信信号パワーに関連する
値から受信信号の有音と無音を判定し、受信信号が無音
のとき、前記適応ディジタルフィルタの適応動作を禁止
し、受信信号が有音のとき、受信信号と送信信号のパワ
ー比を求め、そのパワー比にマージンを付加した値と送
信信号の有音無音判定用しきい値とを比較し、前者が後
者よりも小さい場合に送信信号は有音と判定され、次に
受信信号と残差信号のパワー比を求め、そのパワー比に
マージンを付加した値とダブルトーク判定用しきい値と
を比較し、前者が後者よりも小さい場合にダブルトーク
と判定され、前記適応ディジタルフィルタの適応動作を
禁止する。一方、送信信号が無音と判定されると、前記
適応ディジタルフィルタの適応動作禁止を解除すると共
に前記ダブルトーク検出しきい値を急速に減少させる。
なお、前記ダブルトーク判定用しきい値は、受信信号と
残差信号のパワーに関連する値の比と、その値の過去の
値と、前記パワーに関連する値の比にマージンを付加し
た値を積分処理することにより更新する。だたし、前記
受信信号が無音の場合はダブルトーク判定用しきい値を
保存する。That is, sound and silence of the received signal are determined from the value related to the received signal power. When the received signal is silent, the adaptive operation of the adaptive digital filter is inhibited. The power ratio between the received signal and the transmitted signal is obtained, and a value obtained by adding a margin to the power ratio is compared with a threshold for determining the presence or absence of sound or silence of the transmitted signal. If the former is smaller than the latter, the transmitted signal is present. Then, the power ratio between the received signal and the residual signal is calculated, and the value obtained by adding a margin to the power ratio is compared with the threshold value for double talk determination. If the former is smaller than the latter, the double ratio is determined. Talk is determined, and the adaptive operation of the adaptive digital filter is prohibited. On the other hand, if it is determined that the transmission signal is silent, the prohibition of the adaptive operation of the adaptive digital filter is canceled and the threshold value of the double talk detection is rapidly reduced.
Note that the threshold value for double talk determination is a value obtained by adding a margin to the ratio of the value related to the power of the received signal and the residual signal, the ratio of the past value of the value, and the value related to the power. Is updated by integrating However, if the received signal is silent, the threshold value for double talk determination is stored.
【０００８】本発明では特に、前記送信信号の有音無音
判定を行なう際、送信信号のパワーそのものではなく、
受信信号と送信信号のパワーに関連する値の比を用い、
さらに判定に用いるしきい値を固定の値ではなく、前記
パワーに関連する値の比とその過去の値を積分処理し、
適応が禁止されていない期間に更新するようにした。[0008] In the present invention, in particular, when performing the sound / non-speech determination of the transmission signal, not the power itself of the transmission signal but the power itself of the transmission signal is determined.
Using the ratio of values related to the power of the received signal and the transmitted signal,
Further, the threshold value used for the determination is not a fixed value, but the ratio of the value related to the power and its past value are integrated,
Updated during periods when adaptation is not prohibited.
【０００９】上記のようにエコーキャンセラのダブルト
ーク検出制御装置および制御方法を構成することで、送
信信号の有音無音判定しきい値はエコー経路の特性に合
わせて適切に更新される、すなわちエコー経路の減衰量
が大きいときは、受信信号と送信信号のレベル差が大き
く、しきい値は減少し、結果として送信信号が小さくて
も無音と判定されにくくなる。逆に、エコー経路の減衰
量が小さいときは受信信号と送信信号のレベル差は小さ
く、しきい値は増大し、送信信号がある程度大きくても
無音と判定されるようになる。ただし上記しきい値は、
近端話者音声が存在し、エコーキャンセラの適応が停止
されている期間は更新されずに、保存されている。この
動作によりエコー経路の特性が異なる場合でも、適切に
送信信号の有音無音判定が行なわれ、前記課題を解決で
きる。By configuring the double-talk detection control apparatus and control method of the echo canceller as described above, the threshold for determining the presence or absence of sound in the transmission signal is appropriately updated in accordance with the characteristics of the echo path. When the attenuation of the path is large, the level difference between the received signal and the transmitted signal is large, and the threshold value is reduced. As a result, even if the transmitted signal is small, it is difficult to determine that there is no sound. Conversely, when the amount of attenuation in the echo path is small, the level difference between the received signal and the transmitted signal is small, the threshold value is increased, and even if the transmitted signal is somewhat large, it is determined that there is no sound. However, the above threshold is
The period in which the near-end speaker's voice exists and the echo canceller adaptation is stopped is stored without being updated. Even if the characteristics of the echo path are different due to this operation, the sound / non-speech determination of the transmission signal is appropriately performed, and the above problem can be solved.
【００１０】[0010]
【発明の実施の形態】図１は本発明の実施の形態に係る
ダブルトーク検出制御装置の動作を説明するための、ダ
ブルトーク検出器の構成ブロック図である。DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of a double talk detector for explaining the operation of a double talk detection control device according to an embodiment of the present invention.
【００１１】以下に図１を用いてダブルトーク検出器の
動作を説明する。ダブルトーク検出器は、端子２０、２
１、２２からそれぞれ残差信号ｅ（ｎ）、受信信号ｘ
（ｎ）、送信信号ｙ（ｎ）を受け、パワー検出器２３、
２４、２５でそれぞれのパワーＰｅ（ｎ）、Ｐｘ
（ｎ）、Ｐｙ（ｎ）を算出する。このうち、まずパワー
Ｐｘ（ｎ）を比較器２８で受信信号の無音検出しきい値
ＸＴＨと比較して、Ｐｘ（ｎ）＜ＸＴＨの場合、受信信
号は無音であると判定し、信号”０”を３１のしきい値
設定手段Ａおよび適応禁止信号発生部３５に送る。The operation of the double talk detector will be described below with reference to FIG. The double talk detector is connected to terminals 20, 2
1 and 22, the residual signal e (n) and the received signal x
(N), receives the transmission signal y (n), receives the power detector 23,
The power Pe (n), Px at 24 and 25
(N), Py (n) is calculated. Among these, first, the power Px (n) is compared with the silence detection threshold value XTH of the received signal by the comparator 28, and when Px (n) <XTH, the received signal is determined to be silence, and the signal "0" is determined. "To the threshold setting means A and the adaptation prohibition signal generator 35.
【００１２】Ｐｘ（ｎ）≧ＸＴＨの場合、受信信号は有
音であると判定し、信号”１”を３１のしきい値設定手
段Ａおよび適応禁止信号発生部３５に送ると共に、パワ
ーＰｘ（ｎ）とＰｙ（ｎ）から、パワー比算出手段２７
でパワー比Ｒｙ＿ｘ（ｎ）＝Ｐｙ（ｎ）／Ｐｘ（ｎ）が
計算されたのち、３２のしきい値設定手段Ｂへ送られ、
一方のマージン付加手段３０において、マージンＭＧＮ
２が付加され比較器３４へ送られる。比較器３４は３２
のしきい値設定手段Ｂから受けたしきい値ＴＨ２（ｎ）
と、前記マージン付加手段３０の出力ｙ＿ｘ＿ｍ（ｎ）
とを比較する。If Px (n) ≧ XTH, it is determined that the received signal is a sound, and a signal “1” is sent to the threshold setting means A of 31 and the adaptation prohibition signal generator 35, and the power Px ( n) and Py (n), power ratio calculating means 27
After calculating the power ratio Ry_x (n) = Py (n) / Px (n), the power ratio is sent to the threshold setting means B of 32,
In one margin adding means 30, the margin MGN
2 is added and sent to the comparator 34. The comparator 34 is 32
Threshold value TH2 (n) received from threshold value setting means B
And the output y_x_m (n) of the margin adding means 30
Compare with
【００１３】ｙ＿ｘ＿ｍ（ｎ）＜ＴＨ２（ｎ）の場合、
送信信号は無音であると判定し、信号”０”を３１のし
きい値設定手段Ａおよび適応禁止信号発生部３５に送
る。ｙ＿ｘ＿ｍ（ｎ）≧ＴＨ２（ｎ）の場合、送信信号
は有音であると判定し、信号”１”を３１のしきい値設
定手段Ａおよび適応禁止信号発生部３５に送ると共に、
パワーＰｘ（ｎ）とＰｅ（ｎ）はパワー比算出手段２６
でパワー比Ｒｘ＿ｅ（ｎ）＝Ｐｘ（ｎ）／Ｐｅ（ｎ）が
計算されたのち、３１のしきい値設定手段Ａへ送られ、
もう一方のマージン付加手段２９においてマージンＭＧ
Ｎ１を付加され、３１のしきい値設定手段Ａと比較器３
３へ送られる。比較器３３は、３１のしきい値設定手段
Ａから受けたしきい値ＴＨ１（ｎ）と、前記マージン付
加手段２９の出力ｘ＿ｅ＿ｍ（ｎ）とを比較する。When y_x_m (n) <TH2 (n),
The transmission signal is determined to be silent, and a signal “0” is sent to the threshold setting means A of 31 and the adaptation prohibition signal generator 35. When y_x_m (n) ≧ TH2 (n), it is determined that the transmission signal is sound, and the signal “1” is sent to the threshold setting unit A of 31 and the adaptation inhibition signal generation unit 35, and
The powers Px (n) and Pe (n) are used as power ratio calculating means 26.
After calculating the power ratio Rx_e (n) = Px (n) / Pe (n), the power ratio is sent to the threshold setting means A of 31,
In the other margin adding means 29, the margin MG
N1 is added, and 31 threshold setting means A and comparator 3
Sent to 3. The comparator 33 compares the threshold value TH1 (n) received from the threshold value setting means A with the output x_e_m (n) of the margin adding means 29.
【００１４】ｘ＿ｅ＿ｍ（ｎ）＜ＴＨ１（ｎ）の場合、
ダブルトーク状態と判定し、信号”１”を、ｘ＿ｅ＿ｍ
（ｎ）≧ＴＨ１（ｎ）の場合、シングルトーク（ダブル
トークでない）状態と判定して、信号”０”を、それぞ
れ適応禁止信号発生部３５に送る。When x_e_m (n) <TH1 (n),
It is determined that the state is the double talk state, and the signal “1” is changed to x_e_m
If (n) ≧ TH1 (n), it is determined to be in a single talk (not double talk) state, and a signal “0” is sent to the adaptation prohibition signal generator 35.
【００１５】ここで、しきい値設定手段の動作について
説明する。しきい値設定手段Ａは、Ｒｘ＿ｅ（ｎ）とｘ
＿ｅ＿ｍ（ｎ）の信号を受け、制御信号の状態に応じて
しきい値ＴＨ１（ｎ）の更新を行なう。比較器２８が無
音の判定（Ｐｘ（ｎ）＜ＸＴＨ）をした場合、しきい値
ＴＨ１（ｎ）は保存され、有音の判定（Ｐｘ（ｎ）≧Ｘ
ＴＨ）をした場合、比較器３３の判定がダブルトーク
（信号”１”）かシングルトーク（信号”０”）か、お
よび比較器３４の判定が有音（信号”１”）か無音（信
号”０”）かによって、しきい値ＴＨ１（ｎ）は例えば
次式のように更新される。Here, the operation of the threshold value setting means will be described. The threshold setting means A calculates Rx_e (n) and x
_E_m (n) is received, and the threshold value TH1 (n) is updated according to the state of the control signal. When the comparator 28 determines that there is no sound (Px (n) <XTH), the threshold value TH1 (n) is stored and the sound is determined (Px (n) ≧ X).
TH), the judgment of the comparator 33 is double talk (signal “1”) or single talk (signal “0”), and the judgment of the comparator 34 is sound (signal “1”) or silence (signal “1”). "0"), the threshold value TH1 (n) is updated, for example, by the following equation.
【００１６】シングルトークの場合 ＴＨ１（ｎ＋１）＝（１−ｍ１）×ＴＨ１（ｎ）＋ｍ１
×Ｒｘ＿ｅ（ｎ） ダブルトークの場合 ＴＨ１（ｎ＋１）＝ＴＨ１（ｎ）−ｍ２×［ＴＨ１
（ｎ）−ｘ＿ｅ＿ｍ（ｎ）］ 送信信号が無音の場合 ＴＨ１（ｎ＋１） ＝ ０ ただし、ｍ１，ｍ２は更新の時定数を決定するパラメー
タである。In the case of single talk, TH1 (n + 1) = (1-m1) × TH1 (n) + m1
× Rx_e (n) In case of double talk TH1 (n + 1) = TH1 (n) −m2 × [TH1
(N) -x_e_m (n)] When the transmission signal is silent TH1 (n + 1) = 0 where m1 and m2 are parameters for determining the time constant of update.
【００１７】しきい値設定手段Ｂは、Ｒｙ＿ｘ（ｎ）の
信号を受けて、適応禁止信号の無いとき（適応可能と判
定された期間）だけしきい値ＴＨ２（ｎ）を次式のよう
に更新する。The threshold value setting means B receives the signal Ry_x (n) and sets the threshold value TH2 (n) only when there is no adaptation prohibition signal (period determined to be adaptable) as follows: Update.
【００１８】ＴＨ２（ｎ＋１）＝（１−ｍ３）×ＴＨ２
（ｎ）＋ｍ３×Ｒｙ＿ｘ（ｎ） ただし、ｍ３ は更新の時定数を決定するパラメータで
ある。TH2 (n + 1) = (1-m3) × TH2
(N) + m3 × Ry_x (n) where m3 is a parameter for determining a time constant of update.
【００１９】次に、適応禁止信号発生部３５の動作につ
いて説明する。適応禁止信号発生部３５は比較器２８、
３３、３４の判定結果（信号”０”ないし”１”）を受
けて、それらの組み合わせで適応禁止および禁止解除の
信号を端子３６に出力する。比較器２８の出力が信号”
０”の時、適応禁止の信号を出力する。また、比較器３
３の出力が信号”０”の時、適応禁止解除の信号を、信
号”１”の時、適応禁止の信号を出力する。さらに、比
較器３４の出力が信号”０”の時、適応禁止解除の信号
を出力する。前記以外の状態では直前の状態を継続す
る。Next, the operation of the adaptation inhibition signal generator 35 will be described. The adaptation prohibition signal generator 35 includes a comparator 28,
In response to the determination results (signals “0” to “1”) of 33 and 34, a signal of adaptation inhibition and inhibition release is output to the terminal 36 in a combination thereof. The output of the comparator 28 is a signal "
At the time of 0 ", an adaptation inhibition signal is output.
When the output of the signal No. 3 is a signal "0", a signal for canceling adaptation prohibition is output, and when the output of signal 3 is "1", a signal for prohibition of adaptation is output. Further, when the output of the comparator 34 is a signal "0", a signal for canceling adaptation inhibition is output. In other states, the previous state is continued.
【００２０】なお、上記の説明でパワー比の代わりにパ
ワーを対数変換した値の差分値を用いることも出来る。In the above description, a difference value of a value obtained by logarithmically converting power can be used instead of the power ratio.
【００２１】図３にエコー経路の減衰量が変動したとき
の判定結果における、しきい値を固定にした場合と可変
の場合の差異を示す。しきい値を可変にすることによ
り、しきい値が固定の場合に検出できなかった有音区間
を検出できることが分かる。FIG. 3 shows a difference between the case where the threshold value is fixed and the case where the threshold value is variable, in the determination result when the attenuation amount of the echo path fluctuates. It can be seen that by making the threshold variable, a sounded section that could not be detected when the threshold was fixed can be detected.
【００２２】また、本実施の形態はエコーキャンセラの
ダブルトーク検出制御装置について説明したが、各手段
をステップとすればダブルトーク検出制御方法を与える
事が出来る。In this embodiment, the double talk detection control device of the echo canceller has been described. However, a double talk detection control method can be provided by making each means a step.
【００２３】[0023]
【発明の効果】以上のように、送信信号の有音無音を判
定する比較器３４のしきい値を固定ではなく、受信信号
ｘ（ｎ）と送信信号ｙ（ｎ）のパワー比に応じて可変と
することにより、エコー経路における減衰量の変動によ
らず、送信信号の有音と無音を適切に判定することが出
来る。As described above, the threshold value of the comparator 34 for judging the presence or absence of sound in the transmission signal is not fixed, but is determined according to the power ratio between the reception signal x (n) and the transmission signal y (n). By making it variable, it is possible to appropriately determine the presence or absence of sound in the transmission signal regardless of the variation in the amount of attenuation in the echo path.
【図１】本発明に係わるダブルトーク検出制御装置の実
施の形態を示す概略構成図である。FIG. 1 is a schematic configuration diagram showing an embodiment of a double talk detection control device according to the present invention.
【図２】ダブルトーク検出器を備えるエコーキャンセラ
の一般的な構成を示す図である。FIG. 2 is a diagram illustrating a general configuration of an echo canceller including a double talk detector.
【図３】判定しきい値が固定と可変の場合の動作結果に
おいて本発明の効果を説明する図である。FIG. 3 is a diagram illustrating the effect of the present invention based on operation results when a determination threshold is fixed and variable.
【図４】従来技術におけるダブルトーク検出制御装置の
一例を示す概略構成図である。FIG. 4 is a schematic configuration diagram illustrating an example of a double talk detection control device according to the related art.
【符号の説明】 １ マイク ２ スピーカ ３、９ Ａ／Ｄ変換器 ４、８ Ｄ／Ａ変換器 ５ 減算器 ６ 適応ディジタルフィルタ ７ ダブルトーク検出器 １０ 送信音声信号入力端子 １１ 受信音声信号出力端子 １２ 送信音声信号出力端子 １３ 受信音声信号入力端子 ２０、２１、２２ 音声信号入力端子 ２３、２４、２５ パワー検出器 ２６、２７ パワー比算出手段 ２８、３３、３４ 比較器 ２９、３０ マージン付加手段 ３１ しきい値設定手段Ａ ３２ しきい値設定手段Ｂ ３５ 適応禁止信号発生部 ３６ 適応禁止信号出力端子[Description of Signs] 1 Microphone 2 Speaker 3, 9 A / D Converter 4, 8 D / A Converter 5 Subtractor 6 Adaptive Digital Filter 7 Double Talk Detector 10 Transmission Audio Signal Input Terminal 11 Reception Audio Signal Output Terminal 12 Transmission audio signal output terminal 13 Reception audio signal input terminal 20, 21, 22 Audio signal input terminal 23, 24, 25 Power detector 26, 27 Power ratio calculation means 28, 33, 34 Comparator 29, 30 Margin adding means 31 Threshold value setting means A 32 Threshold value setting means B 35 Adaptation inhibition signal generator 36 Adaptation inhibition signal output terminal
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1374998AJP3357284B2 (en) | 1998-01-27 | 1998-01-27 | Double talk detection control device and double talk detection control method |
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1374998AJP3357284B2 (en) | 1998-01-27 | 1998-01-27 | Double talk detection control device and double talk detection control method |
| Publication Number | Publication Date |
|---|---|
| JPH11215033Atrue JPH11215033A (en) | 1999-08-06 |
| JP3357284B2 JP3357284B2 (en) | 2002-12-16 |
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1374998AExpired - Fee RelatedJP3357284B2 (en) | 1998-01-27 | 1998-01-27 | Double talk detection control device and double talk detection control method |
| Country | Link |
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| JP (1) | JP3357284B2 (en) |
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|---|---|---|---|---|
| US8761385B2 (en) | 2004-11-08 | 2014-06-24 | Nec Corporation | Signal processing method, signal processing device, and signal processing program |
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| US8761385B2 (en) | 2004-11-08 | 2014-06-24 | Nec Corporation | Signal processing method, signal processing device, and signal processing program |
| US9301048B2 (en) | 2004-11-08 | 2016-03-29 | Nec Corporation | Signal processing method, signal processing device, and signal processing program |
| US10453471B2 (en) | 2004-11-08 | 2019-10-22 | Nec Corporation | Signal processing method, signal processing device, and signal processing program |
| Publication number | Publication date |
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| JP3357284B2 (en) | 2002-12-16 |
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