JPH0691579B2 - Voice switch circuit - Google Patents
Voice switch circuitInfo
- Publication number
- JPH0691579B2 JPH0691579B2 JP30432586A JP30432586A JPH0691579B2 JP H0691579 B2 JPH0691579 B2 JP H0691579B2 JP 30432586 A JP30432586 A JP 30432586A JP 30432586 A JP30432586 A JP 30432586A JP H0691579 B2 JPH0691579 B2 JP H0691579B2
- Authority
- JP
- Japan
- Prior art keywords
- amplitude
- reception
- transmission
- input signal
- attenuation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Description
【発明の詳細な説明】 産業上の利用分野 本発明はスピーカホン、テレコンファレンスシステム等
の双方向通話装置に使用されるハウリング防止用の音声
スイッチ回路に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a howling prevention voice switch circuit used in a two-way communication device such as a speakerphone or a teleconference system.
従来の技術 近年、スピーカホン、テレコンファレンスシステムの普
及が目ざましく、これ等の装置ではハウリングの防止の
ために音声スイッチ回路が使用されている。2. Description of the Related Art In recent years, speakerphones and teleconference systems have been remarkably popularized, and in these devices, a voice switch circuit is used to prevent howling.
これ等の装置の性能向上のために、誤動作の無い音声ス
イッチ回路が強く要望されている。In order to improve the performance of these devices, there is a strong demand for a voice switch circuit that does not malfunction.
以下、図面を参照しながら、従来の音声スイッチ回路に
ついて、第３図，第４図を用いて説明を行う。第３図は
従来の音声スイッチ回路のブロック図を示すものであ
る。A conventional voice switch circuit will be described below with reference to FIGS. 3 and 4 with reference to the drawings. FIG. 3 shows a block diagram of a conventional voice switch circuit.
第３図において、31は受話入力信号の入力端子、32は受
話入力信号を減衰させて受話出力信号としてスピーカ33
に出力する受話減衰部、33はスピーカ、34はマイクロホ
ン、35はマイクロホン34の出力である送話入力信号を減
衰させて送話出力信号として出力端子36に出力する送話
減衰部、36は送話出力信号の出力端子、37は受話入力信
号を整流平滑して受話振幅を求める受話振幅計算部、38
は送話入力信号を整流平滑して送話振幅を求める送話振
幅計算部、39は送話振幅を受話振幅で除して振幅比を求
める除算部、40はこの振幅比とあらかじめ設定しておい
たしきい値とを比較し、振幅比がしきい値以上の時は送
話と判定し、振幅比がしきい値以下の時は受話と判定す
る送受判定部、この送受判定部40の判定信号が受話状態
の時には、受話減衰部32の減衰量は低く、送話減衰部35
の減衰量は高く設定され、送話状態の時には逆に、受話
減衰部32の減衰量は高く、送話減衰部35の減衰量は低く
設定される。In FIG. 3, reference numeral 31 is an input terminal of a reception input signal, 32 is a speaker 33 which attenuates the reception input signal and serves as a reception output signal.
To the output attenuator, 33 is a speaker, 34 is a microphone, and 35 is a transmit attenuator that attenuates the transmit input signal output from the microphone 34 and outputs it as an output signal to the output terminal 36. The output terminal of the talk output signal, 37 is a reception amplitude calculator for rectifying and smoothing the reception input signal to obtain the reception amplitude, 38
Is a transmission amplitude calculation unit that rectifies and smoothes the transmission input signal to obtain the transmission amplitude, 39 is a division unit that divides the transmission amplitude by the reception amplitude to obtain the amplitude ratio, and 40 is this amplitude ratio and is preset. When the amplitude ratio is equal to or higher than the threshold value, it is determined to be transmission, and when the amplitude ratio is equal to or lower than the threshold value, it is determined to be reception. When the signal is in the receiving state, the attenuation amount of the receiving attenuating unit 32 is low and the transmitting attenuating unit 35
Is set high, and conversely in the transmitting state, the receiving attenuator 32 has a high amount of attenuation and the transmitting attenuator 35 has a amount of low attenuation.
以上のように構成された従来の音声スイッチ回路につい
て、以下その動作について説明する。The operation of the conventional voice switch circuit configured as described above will be described below.
第４図は第３図の従来例の各部における信号波形を示し
たもので、この図を使用して、第３図の動作説明を行
う。FIG. 4 shows signal waveforms at various portions of the conventional example shown in FIG. 3, and the operation of FIG. 3 will be described with reference to this figure.
第４図において、41は第３図のＡ点の受話入力信号の波
形、42は第３図のＢ点の送話入力信号の波形、43はＣ点
の受話振幅の波形、44はＤ点の送話振幅の波形、45はＥ
点の振幅比の波形、46は送受判定部40内部のしきい値の
レベル、47はＦ点の判定信号の波形、48は受話減衰部32
の減衰量の変化のようす、49は送話減衰部35の減衰量の
変化のようすを示したものである。In FIG. 4, 41 is the waveform of the reception input signal at point A in FIG. 3, 42 is the waveform of the transmission input signal at point B in FIG. 3, 43 is the waveform of the reception amplitude at point C, and 44 is the point D. The waveform of the transmission amplitude of, 45 is E
The waveform of the amplitude ratio of the points, 46 is the threshold level inside the transmission / reception determination unit 40, 47 is the waveform of the determination signal at the F point, and 48 is the reception attenuation unit 32.
The reference numeral 49 represents the change in the attenuation amount of the transmission attenuation unit 35, and the reference numeral 49 represents the change in the attenuation amount of the transmission attenuation unit 35.
なお双方向通話において、着目する端末側の話者を近端
話者、相手側の話者を遠端話者と呼び、以後この用語を
用いて説明する。In a two-way call, the speaker on the terminal side of interest is called the near-end speaker, and the speaker on the other side is called the far-end speaker, and the terms will be used hereinafter.
遠端話者の音声信号である、第４図の受話入力信号41
が、第３図の受話振幅計算部37で整流平滑され、第４図
の受話振幅43となる。一方、この受話入力信号41は第３
図の受話減衰部32を通って受話出力信号となり、スピー
カ33で拡声される。マイクロホン34はこのスピーカ33か
らの反響音とマイクロホン34に向かって話している近端
話者の音声とを収音して送話入力信号42を出力する。こ
の送話入力信号42は、送話振幅計算部38で整流平滑さ
れ、送話振幅44となる。一方、この送話入力信号42は送
話減衰部35を通って送話出力信号となり、出力端子36か
ら出力される。除算部39では送話振幅43を受話振幅44で
除して振幅比45を得る。送受判定部40ではしきい値46と
この振幅比45を比較し、振幅比がしきい値以上の時は送
話、以下の時は受話と判定し判定信号47を受話減衰部32
と送話減衰部35に送る。この２つの減衰部の減衰量は判
定信号47により相反的に制御されており、一方の減衰量
が高くなった時は、必ずもう一方の減衰量が低くなる。Receiving input signal 41 in FIG. 4, which is the voice signal of the far-end speaker.
Is rectified and smoothed by the reception amplitude calculator 37 in FIG. 3 to become the reception amplitude 43 in FIG. On the other hand, this reception input signal 41 is the third
It passes through the reception attenuator 32 in the figure to become a reception output signal, which is amplified by the speaker 33. The microphone 34 picks up the reverberant sound from the speaker 33 and the voice of the near-end speaker talking to the microphone 34, and outputs a transmission input signal 42. This transmission input signal 42 is rectified and smoothed by the transmission amplitude calculation unit 38, and becomes the transmission amplitude 44. On the other hand, the transmission input signal 42 passes through the transmission attenuation unit 35 to become a transmission output signal, which is output from the output terminal 36. The division unit 39 divides the transmission amplitude 43 by the reception amplitude 44 to obtain the amplitude ratio 45. The transmission / reception determination unit 40 compares the threshold value 46 with this amplitude ratio 45. When the amplitude ratio is equal to or higher than the threshold value, it is determined to be transmission.
To the transmission attenuation unit 35. The attenuation amounts of the two attenuating units are reciprocally controlled by the determination signal 47, and when one of the attenuation amounts becomes high, the other attenuation amount becomes low.
すなわち、受話状態では受話減衰部32の減衰量が小さ
く、送話減衰部35の減衰量が大きくなる。送話状態では
逆に受話減衰部32の減衰量は大きく、送話減衰部35の減
衰量は小さくなる。以上のようにして、受話減衰部32の
減衰量は48に示すように、送話減衰部35の減衰量は49に
示すように制御される。That is, in the receiving state, the attenuation amount of the reception attenuation unit 32 is small, and the attenuation amount of the transmission attenuation unit 35 is large. On the contrary, in the transmission state, the attenuation amount of the reception attenuation unit 32 is large and the attenuation amount of the transmission attenuation unit 35 is small. As described above, the attenuation amount of the reception attenuation unit 32 is controlled as indicated by 48, and the attenuation amount of the transmission attenuation unit 35 is controlled as indicated by 49.
このように受話入力信号の振幅と送話入力信号の振幅と
を比較し、振幅の大きい方を減衰させずに出力し、小さ
い方を減衰させて出力する。すなわち、近端話者、遠端
話者の内、より大きな声で話している方の話者音声を優
先して出力する。したがって、ループ利得を下げること
ができ、ハウリングさせることなく、大声量での通話が
可能となる。In this way, the amplitude of the reception input signal and the amplitude of the transmission input signal are compared, and the one with the larger amplitude is output without being attenuated and the one with the smaller amplitude is output after being attenuated. That is, of the near-end speaker and the far-end speaker, the speaker voice speaking in a louder voice is preferentially output. Therefore, it is possible to reduce the loop gain, and it is possible to talk in a large volume without howling.
発明が解決しようとする問題点 しかしながら、上記のような構成では、スピーカ33とマ
イクロホン34との間の反響路の音響結合が大き過ぎる場
合に、受話ブロッキングという誤動作を起こす欠点を有
していた。反響路の音響結合が大きい状態で、受話入力
信号が減衰されずにスピーカ33から拡声されると、マイ
クロホン34に高レベルの反響音が入射する。Problems to be Solved by the Invention However, the above-described configuration has a drawback in that when the acoustic coupling of the echo path between the speaker 33 and the microphone 34 is too large, an erroneous operation called reception blocking occurs. When the acoustic coupling of the echo path is large and the received input signal is amplified by the speaker 33 without being attenuated, a high-level echo sound enters the microphone 34.
その結果、前記振幅比の値が極端に大きくなり、しきい
値を越えてしまい、遠端話者が話しているにもかかわら
ず、近端話者が話始めたと誤判定してしまう。このた
め、受話入力信号に減衰を挿入してしまう。すなわち、
遠端話者音声が切断され、極めて不自然な通話となる。
この現象を防ぐにはしきい値をあらかじめ高く設定して
おけばよいが、必要以上に高くすると今度は送話入力信
号すなわち、近端話者音声に対する感度が低下し、話頭
切断が目だち、通話品質が劣化する。As a result, the value of the amplitude ratio becomes extremely large and exceeds the threshold value, and it is erroneously determined that the near-end speaker has started speaking even though the far-end speaker is speaking. Therefore, attenuation is inserted in the reception input signal. That is,
The far-end talker's voice is cut off, resulting in a very unnatural call.
To prevent this phenomenon, the threshold value should be set high in advance, but if it is set higher than necessary, this time the sensitivity to the transmission input signal, that is, the near-end speaker's voice will decrease, and the head disconnection will be noticeable. , The call quality is degraded.
従来の構成ではスピーカ33からマイクロホン34までの反
響路の音響結合の大きさを正確に推定する機能を持たな
いため、音響結合の大きさに追従させて、しきい値を制
御することは不可能であった。Since the conventional configuration does not have the function of accurately estimating the acoustic coupling magnitude of the echo path from the speaker 33 to the microphone 34, it is impossible to control the threshold value by following the acoustic coupling magnitude. Met.
本発明は上記問題点に鑑み、スピーカ、マイクロホン間
の反響路の音響結合の大きさに追従してしきい値を制御
できるようにし、マイクロホン、スピーカの位置、部屋
の残響特性が変化しても、受話ブロッキングを起こさず
かつ高精度に送話信号を検出することのできる音声スイ
ッチ回路を提供するものである。In view of the above problems, the present invention enables the threshold value to be controlled in accordance with the size of the acoustic coupling of the echo path between the speaker and the microphone, even if the position of the microphone, the speaker, and the reverberation characteristic of the room change. Provided is a voice switch circuit capable of detecting a transmitted signal with high accuracy without causing reception blocking.
問題点を解決するための手段 この目的を達成するために、本発明の音声スイッチ回路
は、受話時には減衰量が小さく送話時には減衰量が大き
く制御されるところの受話入力信号を減衰させて受話出
力信号とする受話減衰部と、受話時には減衰量が大きく
送話時には減衰量が小さく制御されるところの送話入力
信号を減衰させて送話出力信号とする送話減衰部と、前
記受話入力信号の振幅を求める受話入力振幅計算部と、
前記受話出力信号の振幅を求める受話出力振幅計算部
と、前記送話入力信号の振幅を求める送話入力振幅計算
部と、前記送話入力信号の振幅を前記受話入力信号の振
幅で除して送受判定用振幅比を求める第一の除算部と、
前記送話入力信号の振幅を前記受話出力信号の振幅で除
して音響結合測定用振幅比を求める第二の除算部と、ピ
ーク・デップを繰り返して激しく変動する前記音響結合
測定用振幅比の最小値である最小振幅比を求める第一の
デップホールド部と、前記音響結合測定用振幅比のピー
クの上端をむすんだピークの包絡線を求めるピークホー
ルド部と、このピークの包絡線の最小値である最小ピー
ク値を求める第二のデップホールド部と、前記最小振幅
比と前記最小ピーク値とからしきい値を設定するしきい
値計算部と、このしきい値と前記送受判定用振幅比とを
比較して、前記送受判定用振幅比が前記しきい値より大
きい場合に送話、小さい場合に受話と判定し、判定結果
を前記受話減衰部と前記送話減衰部とに送る送受判定部
とから構成されている。Means for Solving the Problems In order to achieve this object, the voice switch circuit of the present invention attenuates the reception input signal where the attenuation amount is small during reception and is controlled to be large during transmission and reception. A reception attenuator that outputs an output signal, a transmission attenuator that attenuates a transmission input signal that is controlled to have a large attenuation amount during reception and a small attenuation amount during transmission, and the reception input A receiver input amplitude calculator that determines the amplitude of the signal,
A reception output amplitude calculation unit that determines the amplitude of the reception output signal, a transmission input amplitude calculation unit that determines the amplitude of the transmission input signal, and the amplitude of the transmission input signal is divided by the amplitude of the reception input signal. A first division unit for obtaining a transmission / reception determination amplitude ratio,
A second divider for obtaining the amplitude ratio for acoustic coupling measurement by dividing the amplitude of the transmission input signal by the amplitude of the reception output signal, and the amplitude ratio for acoustic coupling measurement that fluctuates repetitively by repeating peak and dip. A first dephold section for obtaining the minimum amplitude ratio which is the minimum value, a peak hold section for obtaining the envelope curve of the peak with the upper end of the peak of the amplitude ratio for acoustic coupling measurement, and the minimum value of the envelope curve of this peak. A second dephold unit for obtaining the minimum peak value, a threshold value calculation unit for setting a threshold value from the minimum amplitude ratio and the minimum peak value, and the threshold value and the transmission / reception determination amplitude ratio. And a transmission / reception determination unit for transmitting a determination result to the reception attenuation unit and the transmission attenuation unit when the transmission / reception determination amplitude ratio is larger than the threshold value Composed of and That.
作用 この構成により、常にスピーカからマイクロホンまでの
反響路の音響結合の大きさを測定でき、この測定値に見
合ったしきい値に自動的に設定できる。このため、常に
高感度で誤検出の無い送受判定ができ、ハウリングや話
頭切断の無い双方向通話が可能となる。Action With this configuration, the magnitude of acoustic coupling in the echo path from the speaker to the microphone can be measured at all times, and the threshold value can be automatically set to match the measured value. For this reason, transmission / reception determination can be performed with high sensitivity and without erroneous detection, and two-way communication without howling or disconnecting the talk can be performed.
実施例 以下本発明の一実施例について、図面を参照しながら説
明する。Embodiment An embodiment of the present invention will be described below with reference to the drawings.
第１図において、１は受話入力信号の入力端子、２は受
話入力信号を減衰させて受話出力信号とする受話減衰
部、３はスピーカ、４はマイクロホン、５はマイクロホ
ン４の出力である送話入力信号を減衰させて送話出力信
号とする送話減衰部、６は送話出力信号の出力端子、７
は受話入力信号を整流平滑して受話入力信号の振幅を求
める受話入力振幅計算部、８は受話出力信号を整流平滑
して受話出力信号の振幅を求める受話出力振幅計算部、
９は送話入力信号を整流平滑して送話入力信号の振幅を
求める送話入力振幅計算部、10は送話入力信号の振幅を
受話入力信号の振幅で除して送受判定用振幅比を求める
第一の除算部、11は送話出力信号の振幅を受話入力信号
の振幅で除して音響結合測定用振幅比を求める第二の除
算部、12はピーク・デップを繰り返して激しく変動する
前記音響結合測定用振幅比の最小値である最小振幅比を
求める第一のデップホールド部、13は前記音響結合測定
用振幅比のピークの上端をむすんだピークの包絡線を求
めるピークホールド部、14はこのピークの包絡線の最小
値である最小ピーク値を求める第二のデップホールド
部、15は前記最小振幅比と前記最小ピーク値とからしき
い値を設定するしきい値計算部、16はこのしきい値と前
記送受判定用振幅比とを比較して、前記送受判定用振幅
比が前記しきい値より大きい場合に送話、小さい場合に
受話と判定する送受判定部、この送受判定部16の判定信
号が受話状態の時には、受話減衰部２の減衰量は低く、
送話減衰部５の減衰量は高く設定され、送話状態の時に
は逆に、受話減衰部２の減衰量は高く、送話減衰部５の
減衰量は低く設定される。In FIG. 1, reference numeral 1 is an input terminal of a reception input signal, 2 is a reception attenuating unit for attenuating the reception input signal to obtain a reception output signal, 3 is a speaker, 4 is a microphone, and 5 is an output of the microphone 4. A transmission attenuator for attenuating an input signal into a transmission output signal, 6 is an output terminal for the transmission output signal, 7
Is a receiving input amplitude calculating section for rectifying and smoothing the receiving input signal to obtain the amplitude of the receiving input signal, 8 is a receiving output amplitude calculating section for rectifying and smoothing the receiving output signal to obtain the amplitude of the receiving output signal,
Reference numeral 9 is a transmission input amplitude calculator for rectifying and smoothing the transmission input signal to obtain the amplitude of the transmission input signal, and 10 is a transmission / reception determination amplitude ratio obtained by dividing the amplitude of the transmission input signal by the amplitude of the reception input signal. The first division unit to obtain, 11 is the second division unit to obtain the amplitude ratio for acoustic coupling measurement by dividing the amplitude of the transmission output signal by the amplitude of the reception input signal, and 12 is violently fluctuated by repeating the peak dip. A first dephold unit for obtaining the minimum amplitude ratio which is the minimum value of the acoustic coupling measurement amplitude ratio, 13 is a peak hold unit for obtaining the envelope curve of the peak having the upper end of the peak of the acoustic coupling measurement amplitude ratio, 14 is a second dephold section for obtaining the minimum peak value which is the minimum value of the envelope of this peak, 15 is a threshold value calculation section for setting a threshold value from the minimum amplitude ratio and the minimum peak value, 16 is This threshold and the transmission / reception determination amplitude ratio are In comparison, when the transmission / reception determination amplitude ratio is larger than the threshold value, the transmission / reception determination unit determines that the transmission is received, and when the transmission / reception determination amplitude ratio is smaller than the threshold value, the reception attenuation unit when the determination signal of the transmission / reception determination unit 16 is in the reception state. 2 has low attenuation,
The attenuation amount of the transmission attenuation unit 5 is set high, and conversely in the transmission state, the attenuation amount of the reception attenuation unit 2 is set high and the attenuation amount of the transmission attenuation unit 5 is set low.
第２図は第１図の実施例の各部における信号波形を示し
たもので、この図を使用して、第１図の実施例の動作の
説明を行う。FIG. 2 shows signal waveforms at various portions of the embodiment shown in FIG. 1, and the operation of the embodiment shown in FIG. 1 will be described with reference to this drawing.
第２図において、21は第１図のＡ点の受話入力振幅の波
形、22は第１図のＢ点の受話出力振幅の波形、23はＣ点
の送話入力振幅の波形、24はＤ点の送受判定用振幅比の
波形、25はＥ点の音響結合測定用振幅比の波形、251は
Ｆ点の最小振幅比の波形、252はＧ点のピークの包絡線
の波形、253はＨ点の最小ピーク値の波形、26はＩ点の
しきい値の波形、27はＪ点の判定信号の波形、28は受話
減衰部２の減衰量の変化のようす、29は送話減衰部５の
減衰量の変化のようすを示す。In FIG. 2, 21 is a waveform of the reception input amplitude at point A in FIG. 1, 22 is a waveform of the reception output amplitude at point B of FIG. 1, 23 is a waveform of the transmission input amplitude at point C, and 24 is D. Amplitude ratio waveform for transmission / reception determination at point 25, Waveform of amplitude ratio for acoustic coupling measurement at point E, 251 is waveform of minimum amplitude ratio at point F, 252 is waveform of peak envelope at point G, and 253 is H. The waveform of the minimum peak value of the point, 26 is the waveform of the threshold value of the point I, 27 is the waveform of the judgment signal of the point J, 28 is the change of the attenuation amount of the reception attenuator 2, 29 is the attenuator 5 The change in the attenuation amount of is shown.
遠端話者の音声信号である受話入力信号が第１図の受話
入力振幅計算部７で整流平滑され、第２図の受話入力振
幅21となる。一方、この受話入力信号は第１図の受話減
衰部２を通って受話出力信号となり、スピーカ３で拡声
される。この受話出力信号が受話出力振幅計算部８で整
流平滑され、第２図の受話出力振幅22となる。マイクロ
ホン４はこのスピーカ３からの反響音とマイクロホン４
に向かって話している近端話者の音声とを収音して送話
入力信号を出力する。この送話入力信号は、送話入力振
幅計算部９で整流平滑され、送話入力振幅23となる。一
方、この送話入力信号は送話減衰部５を通って送話出力
信号となり、出力端子６から出力される。第一の除算部
10では、送話入力振幅23を受話入力振幅22で除して、送
受判定用振幅比25を得る。第二の除算部９では、送話入
力振幅24を受話出力振幅23で除して、音響結合測定用振
幅比25を得る。The reception input signal, which is the voice signal of the far-end speaker, is rectified and smoothed by the reception input amplitude calculation unit 7 in FIG. 1 and becomes the reception input amplitude 21 in FIG. On the other hand, the received voice input signal passes through the received voice attenuator 2 in FIG. 1 to become a received voice output signal, which is amplified by the speaker 3. This reception output signal is rectified and smoothed by the reception output amplitude calculation section 8 and becomes the reception output amplitude 22 shown in FIG. The microphone 4 receives the reverberant sound from the speaker 3 and the microphone 4
It collects the voice of the near-end speaker who is speaking to and outputs the transmission input signal. The transmission input signal is rectified and smoothed by the transmission input amplitude calculation unit 9 to have the transmission input amplitude 23. On the other hand, this transmission input signal passes through the transmission attenuation unit 5 to become a transmission output signal, which is output from the output terminal 6. First division
In 10, the transmission input amplitude 23 is divided by the reception input amplitude 22 to obtain the transmission / reception determination amplitude ratio 25. The second divider 9 divides the transmission input amplitude 24 by the reception output amplitude 23 to obtain the acoustic coupling measurement amplitude ratio 25.
遠端話者だけが話しており受話状態にある第２図に示す
時刻T1〜T2では、この音響結合測定用振幅比25はスピー
カ、マイクロホンで構成される反響路の音響結合の大き
さを示す。近端話者が話し出した時刻T3〜T4では、送話
入力振幅23だけが上昇するため、音響結合測定用振幅比
25は非常に大きな値となる。したがって、反響路の音響
結合の大きさを求めるにはこの音響結合測定用振幅比25
の最小値を求めればよいことがわかる。しかしながら、
時刻T1〜T2の音響結合測定用振幅比25を見ればわかるよ
うに、この音響結合測定用振幅比25は微細に変動してい
る。この変動の程度は、反響路の特性によって大きく異
なる。したがって、音響結合測定用振幅比25の最小値を
反響路の音響結合の大きさとするわけにはいかない。本
発明では以下に述べる方法により、反響路の音響結合強
度を正確に算出している。At times T 1 to T 2 shown in Fig. 2 in which only the far-end speaker is speaking and in the receiving state, the acoustic coupling measurement amplitude ratio 25 is the magnitude of acoustic coupling in the echo path composed of the speaker and the microphone. Indicates. At time T 3 through T 4 near end speaker is Hanashidashi, because only the sending input amplitude 23 is increased, the amplitude ratio for acoustic coupling measurement
25 is a very large value. Therefore, in order to determine the magnitude of acoustic coupling in the echo path, this acoustic coupling measurement amplitude ratio 25
It can be seen that the minimum value of However,
As can be seen from the acoustic coupling measurement amplitude ratio 25 at times T 1 to T 2, the acoustic coupling measurement amplitude ratio 25 slightly changes. The degree of this variation greatly depends on the characteristics of the echo path. Therefore, the minimum value of the acoustic coupling measurement amplitude ratio 25 cannot be set as the acoustic coupling magnitude of the echo path. In the present invention, the acoustic coupling strength of the echo path is accurately calculated by the method described below.
まず、第一のデップホールド部12で音響結合測定用振幅
比25の最小値である最小振幅比信号251を求める。一方
音響結合測定用振幅比25はピークホールド部13にも入力
され音響結合測定用振幅比25のピークの上端をむすんだ
ピークの包絡線252を求める。次に第二のデップホール
ド部14でこのピークの包絡線252の最小値である最小ピ
ーク値253を求める。First, the first dephold unit 12 obtains the minimum amplitude ratio signal 251 which is the minimum value of the acoustic coupling measurement amplitude ratio 25. On the other hand, the acoustic coupling measurement amplitude ratio 25 is also input to the peak hold unit 13 to obtain an envelope curve 252 of the peak having the upper end of the peak of the acoustic coupling measurement amplitude ratio 25. Next, the second dephold unit 14 obtains the minimum peak value 253 which is the minimum value of the envelope 252 of this peak.
この最小振幅比251と最小ピーク値253を詳細に見ると、
最小振幅比251が反響路の音響結合強度の最小値を表
し、最小ピーク値253が最大値を表していることがわか
る。したがって、しきい値計算部15では、この最小振幅
比251と最小ピーク値253とから次式により、しきい値26
を計算する。Looking at this minimum amplitude ratio 251 and minimum peak value 253 in detail,
It can be seen that the minimum amplitude ratio 251 represents the minimum value of the acoustic coupling strength of the echo path, and the minimum peak value 253 represents the maximum value. Therefore, the threshold calculation unit 15 calculates the threshold value 26 from the minimum amplitude ratio 251 and the minimum peak value 253 by the following equation.
To calculate.
しきい値＝２＊最小ピーク値−最小振幅比 ……（１） 送受判定部16では、このようにして求めたしきい値26と
送受判定用振幅比24を比較して、送受判定用振幅比がし
きい値以上の時は送話、以下の時は受話と判定し、判定
信号27を受話減衰部２と送話減衰部５に送る。この２つ
の減衰部の減衰量は相反的に制御されており、一方の減
衰量が高くなった時は、必ずもう一方の減衰量が低くな
る。すなわち、受話状態では受話減衰部２の減衰量が小
さく、送話減衰部５の減衰量が大きくなる。送話状態で
は逆に受話減衰部２の減衰量は大きく、送話減衰部５の
減衰量は小さくなる。以上のようにして、受話減衰部２
の減衰量は28に示すように、送話減衰部５の減衰量は29
に示すように制御される。Threshold = 2 * minimum peak value-minimum amplitude ratio (1) In the transmission / reception determination unit 16, the transmission / reception determination amplitude is compared by comparing the threshold value 26 thus obtained with the transmission / reception determination amplitude ratio 24. When the ratio is equal to or higher than the threshold value, it is determined that the speech is transmitted, and when it is less than the threshold, it is determined that the speech is received, and the determination signal 27 is sent to the reception attenuation section 2 and the transmission attenuation section 5. The attenuation amounts of the two attenuating parts are controlled reciprocally, and when the attenuation amount of one increases, the attenuation amount of the other always decreases. That is, in the receiving state, the attenuation amount of the reception attenuation unit 2 is small and the attenuation amount of the transmission attenuation unit 5 is large. On the contrary, in the transmission state, the attenuation amount of the reception attenuation unit 2 is large and the attenuation amount of the transmission attenuation unit 5 is small. As described above, the reception attenuation unit 2
As shown in 28, the transmission attenuation unit 5 has 29
It is controlled as shown in.
このようにして、音響結合測定用振幅比の値から、反響
路の音響結合強度に見合ったしきい値を自動的に設定す
ることができる。したがって、常に高感度で誤検出の少
ない音声スイッチ動作が可能となる。In this way, a threshold value corresponding to the acoustic coupling strength of the echo path can be automatically set from the value of the acoustic coupling measurement amplitude ratio. Therefore, it is possible to always perform the voice switch operation with high sensitivity and less false detection.
発明の効果 本発明は、音響結合測定用振幅比の最小値である最小振
幅比を求める第一のデップホールド部と、音響結合測定
用振幅比のピークの上端をむすんだピークの包絡線を求
めるピークホールド部と、このピークの包絡線の最小値
である最小ピーク値を求める第二のデップホールド部
と、前記最小振幅比と前記最小ピーク値とからしきい値
を設定するしきい値計算部とで、しきい値設定手段を構
成しており、ピーク・デップを繰り返して激しく変動す
る前記音響結合測定用振幅比から反響路の音響結合強度
を正確に求め、これに見合ったしきい値を自動的に設定
することができる。EFFECTS OF THE INVENTION The present invention finds a first dephold section for obtaining a minimum amplitude ratio, which is the minimum value of the amplitude ratio for acoustic coupling measurement, and an envelope curve of the peak in which the upper end of the peak of the amplitude ratio for acoustic coupling measurement is swollen. A peak hold part, a second dep hold part for obtaining the minimum peak value which is the minimum value of the envelope of the peak, and a threshold value calculation part for setting a threshold value from the minimum amplitude ratio and the minimum peak value. The threshold setting means is configured to accurately obtain the acoustic coupling strength of the echopath from the acoustic coupling measurement amplitude ratio that fluctuates sharply by repeating peak and dip, and automatically sets the threshold value corresponding to this. Can be set as desired.
また、反響路の音響結合強度が大きい場合には、しきい
値を高く、音響結合強度が小さい場合はしきい値を低
く、自動的に設定できるため、常に高感度で、誤検出の
無い音声スイッチ回路が実現できる。When the acoustic coupling strength of the echo path is large, the threshold value is high, and when the acoustic coupling strength is small, the threshold value is low. A switch circuit can be realized.
第１図は本発明の一実施例における音声スイッチ回路の
ブロック図、第２図は第１図の各部における信号の波形
図、第３図は従来の音声スイッチ回路のブロック図、第
４図は第３図の各部における信号の波形図である。 ２……受話減衰部、５……送話減衰部、７……受話入力
振幅計算部、８……受話出力振幅計算部、９……送話入
力振幅計算部、10……第一の除算部、11……第二の除算
部、12……第一のデップホールド部、13……ピークホー
ルド部、14……第二のデップホールド部、15……しきい
値計算部、16……送受判定部。FIG. 1 is a block diagram of a voice switch circuit according to an embodiment of the present invention, FIG. 2 is a waveform diagram of signals in each part of FIG. 1, FIG. 3 is a block diagram of a conventional voice switch circuit, and FIG. FIG. 4 is a waveform chart of signals in each part of FIG. 3. 2 ... Reception attenuation unit, 5 ... Transmission attenuation unit, 7 ... Reception input amplitude calculation unit, 8 ... Reception output amplitude calculation unit, 9 ... Transmission input amplitude calculation unit, 10 ... First division Section, 11 ...... second division section, 12 ...... first dep hold section, 13 ...... peak hold section, 14 ...... second dep hold section, 15 ...... threshold calculation section, 16 ...... Transmission / reception determination unit.
Claims (1)
量が大きく制御されるところの受話入力信号を減衰させ
て受話出力信号とする受話減衰部と、受話時には減衰量
が大きく送話時には減衰量が小さく制御されるところの
送話入力信号を減衰させて送話出力信号とする送話減衰
部と、前記受話入力信号の振幅を求める受話入力振幅計
算部と、前記受話出力信号の振幅を求める受話出力振幅
計算部と、前記送話入力信号の振幅を求める送話入力振
幅計算部と、前記送話入力信号の振幅を前記受話入力信
号の振幅で除して送受判定用振幅比を求める第一の除算
部と、前記送話入力信号の振幅を前記受話出力信号の振
幅で除して音響結合測定用振幅比を求める第二の除算部
と、ピーク・デップを繰り返して激しく変動する前記音
響結合測定用振幅比の最小値である最小振幅比を求める
第一のデップホールド部と、前記音響結合測定用振幅比
のピークの上端をむすんだピークの包絡線を求めるピー
クホールド部と、このピークの包絡線の最小値である最
小ピーク値を求める第二のデップホールド部と、前記最
小振幅比と前記最小ピーク値とからしきい値を設定する
しきい値計算部と、このしきい値と前記送受判定用振幅
比とを比較して、前記送受判定用振幅比が前記しきい値
より大きい場合に送話、小さい場合に受話と判定し、判
定結果を前記受話減衰部と前記送話減衰部とに送る送受
判定部とを具備したことを特徴とする音声スイッチ回
路。1. A reception attenuating unit for attenuating a reception input signal to produce a reception output signal, where the attenuation amount is small during reception and the attenuation amount is controlled large during transmission, and the attenuation amount is large during transmission and attenuation during transmission. A transmission attenuation unit that attenuates a transmission input signal whose amount is controlled to be a small amount as a transmission output signal, a reception input amplitude calculation unit that obtains the amplitude of the reception input signal, and an amplitude of the reception output signal. A desired reception output amplitude calculation unit, a transmission input amplitude calculation unit that determines the amplitude of the transmission input signal, and an amplitude ratio for transmission / reception determination by dividing the amplitude of the transmission input signal by the amplitude of the reception input signal. A first divider, a second divider that divides the amplitude of the transmission input signal by the amplitude of the reception output signal to obtain an amplitude ratio for acoustic coupling measurement, and a peak-deep repetition that fluctuates drastically. Amplitude for acoustic coupling measurement The first dephold section for obtaining the minimum amplitude ratio, which is the minimum value of, the peak hold section for obtaining the envelope curve of the peak with the upper end of the peak of the amplitude ratio for acoustic coupling measurement, and the minimum of the envelope curve of this peak. A second dephold unit for obtaining a minimum peak value which is a value, a threshold value calculation unit for setting a threshold value from the minimum amplitude ratio and the minimum peak value, and the threshold value and the transmission / reception determination amplitude ratio. When the transmission / reception determination amplitude ratio is larger than the threshold value, it is transmitted, and when it is smaller, it is determined to be reception, and the determination result is transmitted to the reception attenuation unit and the transmission attenuation unit. And a voice switch circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30432586A JPH0691579B2 (en) | 1986-12-19 | 1986-12-19 | Voice switch circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30432586A JPH0691579B2 (en) | 1986-12-19 | 1986-12-19 | Voice switch circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63155938A JPS63155938A (en) | 1988-06-29 |
| JPH0691579B2 true JPH0691579B2 (en) | 1994-11-14 |
Family
ID=17931654
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP30432586A Expired - Lifetime JPH0691579B2 (en) | 1986-12-19 | 1986-12-19 | Voice switch circuit |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0691579B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4861746B2 (en) * | 2006-05-25 | 2012-01-25 | エアサイクルハウジング株式会社 | Ventilation equipment |
-
1986
- 1986-12-19 JP JP30432586A patent/JPH0691579B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63155938A (en) | 1988-06-29 |
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