JPH0771030B2 - Echo canceller - Google Patents
Echo cancellerInfo
- Publication number
- JPH0771030B2 JPH0771030B2 JP62152437A JP15243787A JPH0771030B2 JP H0771030 B2 JPH0771030 B2 JP H0771030B2 JP 62152437 A JP62152437 A JP 62152437A JP 15243787 A JP15243787 A JP 15243787A JP H0771030 B2 JPH0771030 B2 JP H0771030B2
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- Prior art keywords
- signal level
- output
- measuring means
- echo
- signal
- Prior art date
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- Interconnected Communication Systems, Intercoms, And Interphones (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Description
【発明の詳細な説明】 [産業上の利用分野] 本発明は長距離電話通信回線および会議用電話などにお
ける反響信号を消去する反響消去装置に関するものであ
る。TECHNICAL FIELD The present invention relates to an echo canceller for canceling echo signals in long-distance telephone communication lines, conference phones, and the like.
[従来の技術] 従来,長距離回線,拡声電話機,双方向中継器などの反
響を制御するために反響消去装置が用いられている。[Prior Art] Conventionally, echo cancellers have been used to control the echo of long-distance lines, loudspeakers, two-way repeaters, and the like.
しかし,この反響消去装置においては,反響信号に送話
信号,雑音などの外乱が重畳して送話側入力に入力して
きたときに,反響路の測定精度が低下し,また,反響消
去量も送話側入力の反響信号と外乱信号レベルの比で定
まる値まで低下するという素因を有している。However, in this echo canceller, when a disturbance such as a transmission signal or noise is superimposed on the echo signal and is input to the transmission side input, the measurement accuracy of the echo path is reduced, and the echo cancellation amount is also reduced. It has a predisposition to decrease to a value determined by the ratio of the echo signal of the transmitter side input to the disturbance signal level.
このような原因による反響消去量の低下を防ぐために,
消去残信号を用いて重畳通話を検出する反響消去装置が
提案されている。In order to prevent the reduction of echo cancellation amount due to such causes,
An echo canceller has been proposed which detects a superposed call using an undeleted signal.
従来のこの種の反響消去装置の一例を,第3図に示し説
明すると,1は受話信号が印加される受話入力端子,2は受
話出力信号が得られる受話出力端子,3は送話信号が印加
される送話入力端子,4は送話出力信号が得られる送話出
力端子である。5は反響消去部で,送話入力端子3から
の送話信号から近似反響信号合成回路7の出力を減算す
る減算回路6と,受話入力端子1からの受話入力信号を
入力とし,その出力によって上記減算回路6を制御する
近似反響信号合成回路7とによって構成されている。An example of a conventional echo canceller of this type is shown in FIG. 3 and explained. 1 is a reception input terminal to which a reception signal is applied, 2 is a reception output terminal from which a reception output signal is obtained, and 3 is a transmission signal. The applied speech input terminal 4 is a speech output terminal from which a speech output signal is obtained. Reference numeral 5 denotes an echo canceller, which receives the subtraction circuit 6 for subtracting the output of the approximate echo signal synthesis circuit 7 from the transmission signal from the transmission input terminal 3 and the reception input signal from the reception input terminal 1 and outputs it. It is composed of an approximate echo signal synthesis circuit 7 that controls the subtraction circuit 6.
そして,この反響消去部5は反響路の入出力信号により
特性を測定する手段と,この手段によって得られた反響
路特性に基づき内部にこの反響路特性に近似した反響路
モデルを作り,この反響路モデルに基づき近似反響路信
号を合成し,送話側入力信号より差し引くことにより実
際の反響信号の消去を行う手段を構成している。The echo canceller 5 measures the characteristics of the input and output signals of the echo path, and creates an echo path model that approximates the echo path characteristics internally based on the echo path characteristics obtained by this means. It constitutes means for erasing the actual echo signal by synthesizing the approximate echo path signal based on the path model and subtracting it from the transmitter input signal.
8は受話側の信号レベルを測定する受話側信号レベル測
定回路,9は消去残信号レベルを測定する消去残信号レベ
ル測定回路である。10は受話側信号レベル測定回路8の
出力と消去残信号レベル測定回路9の出力とを入力し,
これらの出力より減衰量(エコーロスとエコーキャンセ
レーションの和)を測定する減衰量測定回路,11は受話
側信号レベル測定回路8からの受話側出力信号レベル
と,消去残信号レベル測定回路9からの消去残信号レベ
ルと減衰量測定回路10よりのレベルとから双方向通話を
検出する重畳通話検出回路で,この重畳通話検出回路11
の出力を近似反響信号合成回路7に供給し,反響路(エ
コーパス,2−3間)の特性を測定する動作を制御するよ
うに構成されている。Reference numeral 8 is a receiver side signal level measuring circuit for measuring the signal level on the receiving side, and reference numeral 9 is a remaining signal level measuring circuit for measuring the remaining signal level. 10 inputs the output of the receiving side signal level measuring circuit 8 and the output of the remaining unerased signal level measuring circuit 9,
An attenuation amount measuring circuit for measuring an attenuation amount (sum of echo loss and echo cancellation) from these outputs, 11 is an output signal level of the receiving side signal from the receiving side signal level measuring circuit 8 and an erasure residual signal level measuring circuit 9 A superposed call detection circuit for detecting a two-way call based on the level of the residual signal to be erased and the level from the attenuation measurement circuit 10.
Is supplied to the approximate echo signal synthesis circuit 7 to control the operation of measuring the characteristics of the echo path (echo path, 2-3).
このように構成された反響消去装置において,受話側信
号レベルおよび消去残信号レベルをそれぞれ受話側信号
レベル測定回路8および消去残信号レベル測定回路9に
て測定し,これらの各出力より減衰量(エコーロスとエ
コーキャンセレーションの和)が減衰量測定回路10によ
り測定される。片方向通話では、消去残信号レベル測定
回路9の出力が受話側信号レベル測定回路8の出力を減
衰量測定回路10で求めた値だけ低下した値とほぼ等しく
なるため,消去残信号レベル測定回路9の出力が受話側
信号レベル測定回路8の出力を減衰量測定回路10で求め
た値だけ低下させた値を大幅に越えた時,双方向通話状
態であると判定出来る。この判定結果により反響路の特
性を測定する動作を制御する。In the echo canceller thus configured, the receiving-side signal level and the remaining unerased signal level are measured by the receiving-side signal level measuring circuit 8 and the remaining unerased signal level measuring circuit 9, respectively. The sum of echo loss and echo cancellation) is measured by the attenuation measuring circuit 10. In a one-way call, the output of the remaining signal level measuring circuit 9 becomes almost equal to the output of the signal level measuring circuit 8 on the receiving side reduced by the value obtained by the attenuation measuring circuit 10. When the output of 9 greatly exceeds the value obtained by lowering the output of the reception side signal level measuring circuit 8 by the value obtained by the attenuation measuring circuit 10, it can be judged that the two-way communication state is established. The operation of measuring the characteristics of the echo path is controlled based on this determination result.
[発明が解決しようとする問題点] しかしながら,このような反響消去装置においては,反
響路(エコーパス,2−3間)が開放となった場合には,
受話入力端子1より入力された受話信号が近似反響信号
合成回路7および減算回路6を通り消去残信号レベル測
定回路9に入力され,その出力は増大し,重畳通話検出
回路11にて,あたかも重畳通話であるがごとく判定し,
反響消去部5の反響モデルの修正停止あるいは修正速度
の低下を行い,しばらくの間,あたかもエコーの様に送
信出力端子に信号を出力するという欠点があった。[Problems to be Solved by the Invention] However, in such an echo canceller, when the echo path (echo path, 2-3) is opened,
The reception signal input from the reception input terminal 1 passes through the approximate reverberation signal synthesizing circuit 7 and the subtraction circuit 6 and is input to the residual signal level measuring circuit 9, and its output is increased. Judge as if it was a call,
There is a drawback that the correction of the echo model of the echo canceller 5 is stopped or the correction speed is reduced, and a signal is output to the transmission output terminal like an echo for a while.
これについて詳記すれば,反響路(エコーパス)が開放
となった場合には,送話側入力信号は無くなり,このと
き送話側出力信号(消去残信号)は近似反響信号と等し
くなり消去残エコーは増大されて送話側出力に出力さ
れ,通話品質の劣化となる。したがって,反響路が開放
となった場合,速やかに反響路モデルを0の方向に収束
させなければならない。しかし,前記重畳通話検出にお
いては,反響路の開放により減衰量が変わったにもかか
わらず,減衰量測定回路の測定の遅れにより開放前の測
定値を使用するため,あたかも重畳通話であるのごとく
判定し,反響路モデルの修正停止あるいは修正速度を下
げてしまい,通話品質の劣化を招くという欠点があっ
た。More specifically, when the echo path is open, the input signal on the transmitting side disappears, and at this time, the output signal on the transmitting side (remaining signal to be erased) becomes equal to the approximate echo signal, and the remaining signal to be erased remains. The echo is increased and output to the output of the transmitting side, resulting in deterioration of speech quality. Therefore, when the echo path is opened, the echo path model must be promptly converged in the direction of 0. However, in the above-mentioned superposed call detection, the measured value before the opening is used due to the delay in the measurement of the attenuation measurement circuit even though the attenuation amount changes due to the opening of the echo path, so that it is as if it is a superposed call. Judgment was made, and the correction of the echo path model was stopped or the speed of correction was reduced, resulting in the deterioration of the call quality.
この問題を解決するため,従来送信入力レベルを測定し
開放状態を検出することにより対処する方法が考えられ
ているが,送信入力レベルを定められたスレッシュホー
ルドレベルで比較するため,送話側入力信号に含まれる
直流分により誤動作したり,直流分の影響を除く程度の
スレッシュホールドとすると信号の小さな時,回線開放
と見なし,重畳通話が検出出来ない等の問題が有る。In order to solve this problem, a method of dealing with the problem by measuring the transmission input level and detecting the open state has been considered in the past. However, in order to compare the transmission input level with a predetermined threshold level, the transmitter input If the DC component contained in the signal causes a malfunction, or if the threshold is set to remove the influence of the DC component, there is a problem that when the signal is small, the line is considered to be open and the superimposed call cannot be detected.
そこで,本発明は以上の点に鑑み,このような問題を解
決すると共にかかる欠点を除去すべくなされたもので,
その目的は簡単な構成によって,通常状態での重畳通話
検出の機能を妨げることなく,反響路の開放を素速く検
出し,重畳通話検出の誤動作を防ぎ,通話品質の劣化を
防止することができる反響消去装置を提供することにあ
る。Therefore, in view of the above points, the present invention has been made to solve such problems and to eliminate such defects.
Its purpose is to make it possible to detect the opening of the echo path quickly, prevent malfunction of superimposed call detection, and prevent deterioration of call quality without disturbing the function of superimposed call detection in a normal state with a simple configuration. An object is to provide an echo canceller.
[問題点を解決するための手段] 本発明によれば、反響路の入出力信号より反響路特性を
測定する反響路特性測定手段と、該反響路特性測定手段
によって得られた反響路特性に基づき、近似反響路信号
を合成することにより実際の反響信号の消去を行う消去
手段と、消去残信号レベルを測定する消去残信号レベル
測定手段と、受話側信号レベルを測定する受話側信号レ
ベル測定手段と、前記消去残信号レベル測定手段からの
出力と前記受話側信号レベル測定手段からの出力とを基
に、受話出力端から減算回路出力までの減衰量を測定す
る減衰量測定手段と、前記消去残信号レベル測定手段か
らの出力と前記受話側信号レベル測定手段からの出力と
前記減衰量測定手段からの出力とを基に、前記反響路の
特性を測定する前記反響路特性測定手段を制御する重畳
通話検出手段とを有する反響消去装置において、送話入
力レベルを測定する送話側信号レベル測定手段の出力
と、前記消去残信号レベル測定手段の出力と、前記受話
側信号レベル測定手段の出力と、前記重畳通話検出手段
の出力とを基に、前記減衰量測定手段を制御する制御手
段とを設けたことを特徴とする反響消去装置が得られ
る。[Means for Solving the Problems] According to the present invention, the echo path characteristic measuring means for measuring the echo path characteristic from the input / output signals of the echo path and the echo path characteristic obtained by the echo path characteristic measuring means are provided. Based on this, an erasing means for erasing the actual echo signal by synthesizing the approximate echo path signal, an erasure residual signal level measuring means for measuring the erasure residual signal level, and a reception side signal level measurement for measuring the reception side signal level Means for measuring the amount of attenuation from the reception output end to the subtraction circuit output based on the output from the remaining signal level measuring means and the output from the receiving side signal level measuring means, The echo path characteristic measuring means for measuring the characteristic of the echo path based on the output from the residual signal level measuring means, the output from the receiving side signal level measuring means, and the output from the attenuation measuring means. In the echo canceller having a superposed call detecting means for controlling the above, the output of the transmitting side signal level measuring means for measuring the transmitting input level, the output of the remaining unerased signal level measuring means, and the receiving side signal level measurement. An echo canceller is provided which is provided with control means for controlling the attenuation amount measuring means based on the output of the means and the output of the superimposed call detecting means.
更に本発明によれば、前記制御手段は、前記消去残信号
レベル測定手段の出力と前記送話側信号レベル測定手段
の出力とを比較する第1の比較手段と、前記送話側信号
レベル測定手段の出力と前記受話側信号レベル測定手段
との出力を比較する第2の比較手段と、前記受話側信号
レベル測定手段の出力と定められた設定値とを比較する
第3の比較手段と、前記第1、前記第2及び前記第3の
比較手段の出力と、前記重畳通話検出手段の出力とを基
に反響路の状態を判定する判定手段とを有することを特
徴とする反響消去装置が得られる。Further, according to the invention, the control means comprises a first comparing means for comparing the output of the erasure residual signal level measuring means with the output of the transmitting side signal level measuring means, and the transmitting side signal level measurement. Second comparing means for comparing the output of the means and the output of the receiving side signal level measuring means, and third comparing means for comparing the output of the receiving side signal level measuring means with a predetermined set value. An echo canceller having a judging means for judging the state of the echo path based on the outputs of the first, second and third comparing means and the output of the superimposed call detecting means. can get.
[実施例] 第1図は本発明の第1の実施例のブロック図である。[Embodiment] FIG. 1 is a block diagram of a first embodiment of the present invention.
第1図において,参照数字1〜11は,第3図と同一構成
要素を示している。12は,送話側信号レベル測定回路で
送話側に入力する信号のレベルを求める。In FIG. 1, reference numerals 1 to 11 indicate the same constituent elements as in FIG. 12 is the signal level measuring circuit on the transmitting side, which determines the level of the signal input to the transmitting side.
制御回路13は,送話側信号レベル,受話側信号レベルと
消去残信号レベルを基に反響路が開放状態か否かを判定
し,開放状態と判定した時,減衰量測定回路10を制御し
測定した減衰量の値を制御することにより重畳通話検出
回路11の誤動作を防いでいる。この制御回路13の動作を
反響消去装置に入力する信号の状態に対応して説明す
る。(制御回路13の詳細は第2図参照) (1) 無通話状態 本状態は受話側,送話側共に信号の無い状態で反響路が
開放状態となって;重畳通話検出回路が誤動作しても,
信号が無いため特に問題は無い。このため減衰量測定回
路への制御は行なわない。The control circuit 13 determines whether or not the echo path is in the open state based on the signal level on the transmitting side, the signal level on the receiving side, and the level of the remaining signal to be erased. When the open state is determined, the control circuit 13 controls the attenuation measuring circuit 10. By controlling the value of the measured attenuation amount, the malfunction of the superimposed call detection circuit 11 is prevented. The operation of the control circuit 13 will be described according to the state of the signal input to the echo canceller. (See Fig. 2 for details of the control circuit 13) (1) No call state In this state, the echo path is open with no signal on both the receiving side and the transmitting side; the superimposed call detection circuit malfunctions. Also,
Since there is no signal, there is no particular problem. Therefore, the attenuation amount measuring circuit is not controlled.
(2) 反響消去装置の有る側の話者だけが話している
時,本状態は,受話側に信号が無く,送話側にだけ信号
が有る状態である。この状態では,受話側に信号が無い
ため近似反響信号も無く,反響路が開放となり重畳通話
検出回路が誤動作しても問題は無いため,減衰量測定回
路10に対する制御は行なわない。この時の各信号の関係
は次の様になる。(2) When only the speaker on the side with the echo canceller is speaking, in this state, there is no signal on the receiving side and only the transmitting side has a signal. In this state, since there is no signal on the receiving side, there is no approximate echo signal, and there is no problem even if the echo path is opened and the superimposed speech detection circuit malfunctions. Therefore, the attenuation amount measurement circuit 10 is not controlled. The relationship of each signal at this time is as follows.
受話信号レベル≦送話信号レベル 受話信号レベル≦消去残信号レベル 消去信号レベル=送話信号レベル (3) 両側に信号が有る時 本状態は受話側,送話側共に信号の有る状態である。Received signal level ≤ transmitted signal level Received signal level ≤ erased residual signal level Deleted signal level = transmitted signal level (3) When there is a signal on both sides In this state, there is a signal on both the receiving side and the transmitting side.
本状態で反響路が正常な時は,減衰量測定回路10に対す
る制御は行なわず,反響路が開放となった状態でも反響
路の減衰量測定が不可能なため減衰量測定回路10に対す
る制御を行なわない。In this state, when the echo path is normal, the attenuation measurement circuit 10 is not controlled. Even when the echo path is open, the attenuation measurement of the echo path is impossible, so the attenuation measurement circuit 10 is controlled. Do not do.
本状態での各信号の関係は次の様になる。The relationship of each signal in this state is as follows.
受話信号レベル≦送話信号レベル+THα 受話信号レベル≦消去残信号レベル+THρ 消去残信号レベル≦送話信号レベル+THγ ここでTHα,THρ,THγは,反響路特性検出用の定数であ
る。Receiving signal level ≤ Transmitting signal level + TH α Receiving signal level ≤ Remaining erased signal level + TH ρ Remaining erased signal level ≤ Transmitting signal level + TH γ where TH α , TH ρ and TH γ are constants for detecting echo path characteristics. Is.
(4) 反響消去装置の有る側の相手側だけが話してい
る時 本状態は受話側にだけ信号の有る状態である。(4) When only the other party on the side with the echo canceller is speaking In this state, there is a signal only on the receiving side.
本状態で反響路が正常な時の各信号の関係は次の様にな
っている。The relationship of each signal when the echo path is normal in this state is as follows.
受話信号レベルと送話信号レベルの関係は決まらず 受話信号レベル≧消去残信号レベル+THρ 消去残信号レベル≦送話信号レベル+THγ 本状態は,正常動作なので減衰量測定回路10に対する,
制御を行なう必要は無い。The relationship between the received signal level and the transmitted signal level is not determined. Received signal level ≥ erase remaining signal level + TH ρ erase remaining signal level ≤ transmitted signal level + TH γ Since this state is normal operation,
There is no need to control.
本状態で反響路が開放となると送話側出力に近似反響信
号が出力され,重畳通話検出回路によりあたかも,重畳
通話の状態の様に誤検出される。この誤検出を防ぐため
に減衰量測定回路10に対する制御を行なう必要が有る。
この状態での各信号の関係は, 受話信号レベル≧送話信号レベル+THα 受話信号レベル≦消去残信号レベル+THρ 消去残信号レベル≧送話信号レベル+THγ となる。When the echo path is opened in this state, an approximate echo signal is output to the transmitter output, and the superimposed call detection circuit erroneously detects it as if it were in the superimposed call state. In order to prevent this erroneous detection, it is necessary to control the attenuation amount measuring circuit 10.
The relationship of each signal in this state is as follows: reception signal level ≥ transmission signal level + TH α reception signal level ≤ erase remaining signal level + TH ρ erase remaining signal level ≥ transmission signal level + TH γ .
以上各状態を比較すると次の状態の時減衰量測定回路に
対する制御が必要となる。Comparing the above states, it is necessary to control the time attenuation amount measuring circuit in the next state.
受話信号が有り, 受話信号レベル≧送話信号レベル+THα 受話信号レベル≦消去残信号レベル+THρ でさらに 消去残信号レベル≧送話信号レベル+THγの時 本発明では上記条件を検出するため送話側レベル測定器
12と制御回路13を設けている。また,第3図は制御回路
13の詳細図である。When there is a received signal and the received signal level ≥ the transmitted signal level + TH α The received signal level ≤ the erase remaining signal level + TH ρ and the erase remaining signal level ≥ the transmitted signal level + TH γ In the present invention, the transmission is performed to detect the above condition. Talkside level measuring instrument
12 and a control circuit 13 are provided. Fig. 3 shows the control circuit
13 is a detailed view of 13. FIG.
本発明を図2と図3を使用し説明する。The present invention will be described with reference to FIGS.
受話信号は,受話側信号レベル測定回路8に入力し,信
号のレベルが測定される。この結果は,減衰量測定回路
10と重畳通話検出回路11に送られると同時に制御回路13
に送られる。制御回路13では,入力された受話側信号レ
ベルを比較器C133により設定されたスレッシュホールド
THXと比較し受話信号の有無を判定する。The reception signal is input to the reception side signal level measuring circuit 8 and the signal level is measured. This result is the attenuation measurement circuit
10 and the superimposed call detection circuit 11 and at the same time the control circuit 13
Sent to. In the control circuit 13, the input signal level on the receiving side is set to the threshold value set by the comparator C133.
The presence or absence of the received signal is compared with TH X.
受話側信号レベルは同時に送話側信号レベル測定回路12
により測定された送話信号の値と設定されたスレッシュ
ホールドTHαを持つ比較器B132によりどちらが大きいか
比較され,受話信号レベルとスレッシュホールドTHαを
持つ送話信号レベル,どちらが大きいか判定される。The signal level of the receiving side is simultaneously measured by the signal level measuring circuit 12 of the transmitting side.
Which is larger by the comparator B132 having the threshold TH α set by the value of the transmission signal measured by the above, and it is judged which is larger, the reception signal level or the transmission signal level having the threshold TH α. .
送話信号レベルは同時に,消去残信号レベル測定回路9
により測定された消去残信号の値と設定されたスレッシ
ュホールドTHγを持つ比較器A131によりどちらが大きい
か比較され,送話信号とスレッシュホールドTHγを持つ
消去残信号レベルどちらが大きいか判定される。At the same time, the transmission signal level is measured by the erasure residual signal level measuring circuit 9
Which is larger by the comparator A131 having the threshold TH γ set with the value of the remaining unerased signal measured by, and it is determined which of the transmission signal and the remaining unerased signal level having the threshold TH γ is larger.
重畳通話検出回路11では,スレッシュホールドTHρを持
ち受話信号と消去残信号のレベル比較を行なっている。The superposed call detection circuit 11 has a threshold TH ρ and compares the levels of the received signal and the unerased signal.
判定回路134では,比較器A131,比較器B132,比較器C133
と重畳通話検出回路11の出力を基に前記条件を満足する
か否かを判定し,この結果により減衰量測定回路の測定
値を小さくする方向に制御することにより,重畳通話検
出回路11の誤動作を防止する。The determination circuit 134 includes a comparator A131, a comparator B132, and a comparator C133.
And the output of the superimposed call detection circuit 11 are used to determine whether or not the above condition is satisfied, and the result is controlled to decrease the measured value of the attenuation measurement circuit, whereby the superimposed call detection circuit 11 malfunctions. Prevent.
[発明の効果] 以上の説明から明らかなように,本発明によれば,複雑
な手段を用いることなく,送信入力レベルを測定する送
信入力レベル測定回路と,反響路の開放状態を検出する
制御回路とを設けた簡単な回路構成によって,通常状態
での重畳通話検出の機能を妨げることなく,反響路の開
放を素速く検出し,重畳通話検出の誤動作を防ぎ,通話
品質の劣化を防止することができるので,実用上の効果
は極めて大である。[Effects of the Invention] As is apparent from the above description, according to the present invention, a transmission input level measuring circuit for measuring a transmission input level and a control for detecting an open state of an echo path are used without using complicated means. With a simple circuit configuration that includes a circuit, the opening of the echo path can be detected quickly without impairing the function of detecting a superposed call in the normal state, malfunctions of the detection of a superposed call can be prevented, and deterioration of call quality can be prevented. Therefore, the practical effect is extremely large.
第1図は,本発明による反響消去装置の一実施例を示す
ブロック図,第2図は第1図における制御回路の詳細図
を示すブロック図,第3図は従来の反響消去装置の一例
を示すブロック図である。 1……受話入力端子,2……受話出力端子,3……送話入力
端子,4……送話出力端子,5……反響消去部,6……減算回
路,7……近似反響信号合成回路,8……受話側信号レベル
測定回路,9……消去残信号レベル測定回路,10……減衰
量測定回路,11……重畳通話検出回路,12……送話側信号
レベル測定回路,13……制御回路,131……比較器A,132…
…比較器B,133……比較器C,134……判定回路。FIG. 1 is a block diagram showing an embodiment of an echo canceller according to the present invention, FIG. 2 is a block diagram showing a detailed view of a control circuit in FIG. 1, and FIG. 3 is an example of a conventional echo canceller. It is a block diagram shown. 1 …… Receiving input terminal, 2 …… Reception output terminal, 3 …… Sending input terminal, 4 …… Sending output terminal, 5 …… Echo canceller, 6 …… Subtraction circuit, 7 …… Approximate echo signal synthesis Circuit, 8 …… Receiving side signal level measuring circuit, 9 …… Remaining erased signal level measuring circuit, 10 …… Attenuation measuring circuit, 11 …… Superposed call detection circuit, 12 …… Sending side signal level measuring circuit, 13 ...... Control circuit, 131 …… Comparator A, 132…
… Comparator B, 133 …… Comparator C, 134 …… Judgment circuit.
Claims (2)
する反響路特性測定手段と、該反響路特性測定手段によ
って得られた反響路特性に基づき、近似反響路信号を合
成することにより実際の反響信号の消去を行う消去手段
と、消去残信号レベルを測定する消去残信号レベル測定
手段と、受話側信号レベルを測定する受話側信号レベル
測定手段と、前記消去残信号レベル測定手段からの出力
と前記受話側信号レベル測定手段からの出力とを基に、
受話出力端から減算回路出力までの減衰量を測定する減
衰量測定手段と、前記消去残信号レベル測定手段からの
出力と前記受話側信号レベル測定手段からの出力と前記
減衰量測定手段からの出力とを基に、前記反響路の特性
を測定する前記反響路特性測定手段を制御する重畳通話
検出手段とを有する反響消去装置において、送話入力レ
ベルを測定する送話側信号レベル測定手段の出力と、前
記消去残信号レベル測定手段の出力と、前記受話側信号
レベル測定手段の出力と、前記重畳通話検出手段の出力
とを基に、前記減衰量測定手段を制御する制御手段とを
設けたことを特徴とする反響消去装置。1. An echo path characteristic measuring means for measuring an echo path characteristic from an input / output signal of the echo path, and combining an approximate echo path signal based on the echo path characteristic obtained by the echo path characteristic measuring means. From the erasing means for actually erasing the echo signal, the erasing residual signal level measuring means for measuring the erasing residual signal level, the receiving side signal level measuring means for measuring the receiving side signal level, and the erasing residual signal level measuring means. Based on the output of and the output from the receiving side signal level measuring means,
Attenuation amount measuring means for measuring the amount of attenuation from the reception output end to the subtraction circuit output, output from the residual signal level measuring means, output from the receiving side signal level measuring means, and output from the attenuation amount measuring means In the echo canceller having a superposed call detecting means for controlling the echo path characteristic measuring means for measuring the echo path characteristic, the output of the transmitting side signal level measuring means for measuring the transmitting input level. And a control means for controlling the attenuation amount measuring means based on the output of the erasure remaining signal level measuring means, the output of the receiving side signal level measuring means, and the output of the superposed call detecting means. An echo canceller characterized by the above.
装置において、前記制御手段は、前記消去残信号レベル
測定手段の出力と前記送話側信号レベル測定手段の出力
とを比較する第1の比較手段と、前記送話側信号レベル
測定手段の出力と前記受話側信号レベル測定手段との出
力を比較する第2の比較手段と、前記受話側信号レベル
測定手段の出力と定められた設定値とを比較する第3の
比較手段と、前記第1、前記第2及び前記第3の比較手
段の出力と、前記重畳通話検出手段の出力とを基に反響
路の状態を判定する判定手段とを有することを特徴とす
る反響消去装置。2. The echo canceller according to claim 1, wherein said control means compares the output of said residual signal level measuring means with the output of said transmitting side signal level measuring means. 1 comparing means, a second comparing means for comparing the output of the transmitting side signal level measuring means and the output of the receiving side signal level measuring means, and the output of the receiving side signal level measuring means. Judgment for judging the state of the echo path based on the third comparing means for comparing the set value, the outputs of the first, second and third comparing means, and the output of the superimposed call detecting means. And an echo canceller.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62152437A JPH0771030B2 (en) | 1987-06-20 | 1987-06-20 | Echo canceller |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62152437A JPH0771030B2 (en) | 1987-06-20 | 1987-06-20 | Echo canceller |
Publications (2)
Publication Number | Publication Date |
---|---|
JPS63318821A JPS63318821A (en) | 1988-12-27 |
JPH0771030B2 true JPH0771030B2 (en) | 1995-07-31 |
Family
ID=15540514
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP62152437A Expired - Lifetime JPH0771030B2 (en) | 1987-06-20 | 1987-06-20 | Echo canceller |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0771030B2 (en) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6351531B1 (en) * | 2000-01-21 | 2002-02-26 | Motorola, Inc. | Method and system for controlling echo cancellation using zero echo path, ringing, and off-hook detection |
JP5057109B2 (en) * | 2008-04-24 | 2012-10-24 | Necエンジニアリング株式会社 | Echo canceller |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6053336A (en) * | 1983-09-02 | 1985-03-27 | Nec Corp | Echo canceller |
JPS6156526A (en) * | 1984-08-28 | 1986-03-22 | Toshiba Corp | Echo signal eliminator |
-
1987
- 1987-06-20 JP JP62152437A patent/JPH0771030B2/en not_active Expired - Lifetime
Also Published As
Publication number | Publication date |
---|---|
JPS63318821A (en) | 1988-12-27 |
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