JPS63155938A - Sound switch circuit - Google Patents
Sound switch circuitInfo
- Publication number
- JPS63155938A JPS63155938A JP30432586A JP30432586A JPS63155938A JP S63155938 A JPS63155938 A JP S63155938A JP 30432586 A JP30432586 A JP 30432586A JP 30432586 A JP30432586 A JP 30432586A JP S63155938 A JPS63155938 A JP S63155938A
- Authority
- JP
- Japan
- Prior art keywords
- amplitude
- receiving
- transmitting
- peak
- amplitude ratio
- 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.)
- Granted
Links
- 230000008878 coupling Effects 0.000 claims abstract description 42
- 238000010168 coupling process Methods 0.000 claims abstract description 42
- 238000005859 coupling reaction Methods 0.000 claims abstract description 42
- 230000005540 biological transmission Effects 0.000 claims abstract description 18
- 238000005259 measurement Methods 0.000 claims description 22
- 238000001514 detection method Methods 0.000 abstract description 5
- 230000035945 sensitivity Effects 0.000 abstract description 5
- 238000010586 diagram Methods 0.000 description 7
- 238000004891 communication Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発ｑｕ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。DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a voice switch circuit for preventing howling used in two-way communication devices such as speakerphones and teleconference systems.
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、ソチ回路が使用されている。BACKGROUND OF THE INVENTION In recent years, speakerphones and teleconference systems have become widespread, and these devices use voice switching and sochi circuits 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 an audio 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
。Hereinafter, a conventional audio switch circuit will be explained using FIGS. 3 and 4 with reference to the drawings. FIG. 3 shows a block diagram of a conventional audio 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、３６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３
ｅ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４ｏ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３６の減衰量は低く設定される。In FIG. 3, 31 is an input terminal for receiving input signals, 32
33 is a speaker, 34 is a microphone, and 36 is a transmitting input signal output from the microphone 34, which attenuates the receiving input signal and outputting it as a receiving output signal to the speaker 33; 33 is a speaker; 34 is a microphone; Output terminal 3
36 is an output terminal for a transmitting output signal; 37 is a receiving amplitude calculation unit that rectifies and smoothes the receiving input signal to obtain the receiving amplitude; 38 rectifies and smoothes the transmitting input signal and transmits the signal. 39 is a dividing unit that divides the sending amplitude by the receiving amplitude to obtain an amplitude ratio; 40 compares this amplitude ratio with a preset threshold;
A transmitting/receiving determination section that determines that a call is being sent when the amplitude ratio is above a threshold value and determining that a call is being received when the amplitude ratio is below a threshold value, and when the determination signal of this transmitting/receiving determining section 4o is in a receiving state, receiving attenuation is performed. The attenuation amount of the transmitting attenuation section 32 is set low and the attenuation amount of the transmitting attenuation section 35 is set high, and conversely, in the transmitting state, the attenuation amount of the receiving attenuation section 32 is set high and the attenuation amount of the transmitting attenuation section 36 is set low. be done.
以上のように構成された従来の音声スイ・ノテ回路につ
いて、以下その動作について説明する。The operation of the conventional audio switch/note circuit configured as described above will be explained 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 parts of the conventional example of FIG. 3, and the operation of FIG. 3 will be explained using this diagram.
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０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４ｏ内
部のしきい値のレベル、４７は２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３６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 receiving input signal at point A in FIG. 3, 42 is the waveform of the transmitting input signal at point B in FIG. 3, and 43
is the waveform of the receiving amplitude at point 0, 44 is the waveform of the transmitting amplitude at point D, 45 is the waveform of the amplitude ratio at point E, 46 is the level of the threshold inside the sending/receiving judgment unit 4o, and 47 is the judgment at 2 points. signal waveform,
48 shows how the attenuation amount of the receiving attenuation section 32 changes, and 49 shows how the attenuation amount of the sending attenuation section 36 changes.
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 party's side is called the far-end speaker, and these terms will be used in the following description.
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３６ケ通って送話出
力信号となり、出力端子３６から出力される。除算部３
９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。The receiving input signal 41 of FIG. 4 is the voice signal of the far end speaker.
is rectified and smoothed by the reception amplitude calculation unit 37 in FIG.
This is the receiving amplitude 43 in the figure. On the other hand, this reception input signal 41
passes through the reception attenuator 32 shown in FIG. 3, becomes a reception output signal, and is amplified by the speaker 33. The microphone 34 picks up the echo from the speaker 33 and the voice of the near-end speaker speaking into the microphone 34, and outputs a transmission input signal 42. This transmitting input signal 42 is rectified and smoothed by a transmitting amplitude calculating section 38 to obtain a transmitting amplitude 44 . on the other hand,
This transmitting input signal 42 passes through the transmitting attenuator 36 to become a transmitting output signal, which is output from the output terminal 36. Division part 3
9, the transmitting amplitude 43 is divided by the receiving amplitude 44 to obtain the amplitude ratio 45.
get. The transmission/reception determination unit 40 compares the threshold value 46 with this amplitude ratio 45, and when the amplitude ratio is greater than or equal to the threshold value, it is determined that the call is being transmitted, and when it is less than the threshold, it is determined that the call is being received, and the determination signal 47 is sent to the reception attenuation unit 32 and the voice transmission. It is sent to the attenuation section 35. The attenuation amounts of these two attenuation sections are controlled reciprocally by the determination signal 47, and when the attenuation amount of one becomes high, the attenuation amount of the other always 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３
５の減衰量は小さくなる。That is, in the receiving state, the amount of attenuation of the receiving attenuator 32 is small, and the amount of attenuation of the transmitting attenuator 35 is large. Conversely, in the transmitting state, the attenuation amount of the receiving attenuator 32 is large;
5 has a small attenuation amount.
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３６の減衰量は４９に示すように
制御される。As described above, the amount of attenuation of the receiving attenuator 32 is controlled as shown at 48, and the attenuation amount of the sending attenuator 36 is controlled as shown at 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、大音量での通話が
可能となる。In this way, the amplitude of the receiving input signal and the amplitude of the transmitting input signal are compared, and the one with the larger amplitude is output without attenuation, and the one with the smaller amplitude is outputted with attenuation. That is, the voice of the near-end speaker and the far-end speaker who is speaking in a louder voice is given priority and output. Therefore, the loop gain can be lowered, making it possible to talk at a high volume without causing 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 configuration has the disadvantage that if the acoustic coupling in the echo path between the speaker 33 and the microphone 34 is too large, a malfunction called reception blocking occurs. If the received input signal is amplified from the speaker 33 without being attenuated in a state where the acoustic coupling of the echo path is large, high-level reverberant sound will be incident on 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
断が目たち、通話品質が劣化する。As a result, the value of the amplitude ratio becomes extremely large, exceeding 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 into the reception input signal. In other words, the voice of the far end speaker is cut off, resulting in an extremely unnatural conversation. To prevent this phenomenon, it is possible to set the threshold high in advance, but if it is set higher than necessary, the sensitivity to the transmitting input signal, that is, the voice of the near-end speaker will decrease, and the beginning of speech will be cut off. Call quality deteriorates.
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。The conventional configuration does not have a function to accurately estimate the magnitude of acoustic coupling in the echo path from the speaker 33 to the microphone 34, so it is impossible to control the threshold by following the magnitude of the acoustic coupling. 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、誠ピーカの位置、部屋
の残響特性が変化しても、受話プロ・ソキングを起こさ
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 makes it possible to control the threshold value by following the magnitude of acoustic coupling in the reverberation path between the speaker and the microphone, so that the positions of the microphone and the speaker and the reverberation characteristics of the room change. Another object of the present invention is to provide a voice switch circuit that can detect a transmitting signal with high accuracy without causing reception pro-soaking.
問題点を解決するための手段
と、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・ンブ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
のデツプホールド部と、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ツプホールド部と、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。In order to solve the problem and achieve the object, the voice switch circuit of the present invention attenuates the receive input signal, which has a small attenuation amount when receiving a call and a large attenuation amount when transmitting a call. a receiving attenuator that outputs a receiving output signal; a transmitting attenuator that attenuates a transmitting input signal, which is controlled to have a large attenuation amount during reception and a small attenuation amount during transmitting, and outputs a transmitting output signal;
a receiving input amplitude calculating section for calculating the amplitude of the receiving input signal; a receiving output amplitude calculating section for calculating the amplitude of the receiving output signal; a transmitting input amplitude calculating section for calculating the amplitude of the transmitting input signal; a first dividing unit that divides the amplitude of the input signal by the amplitude of the receiving input signal to obtain an amplitude ratio for transmitting/receiving determination;
a second dividing unit that divides the amplitude of the transmitting input signal by the amplitude of the receiving output signal to obtain an amplitude ratio for acoustic coupling measurement; and the amplitude for acoustic coupling measurement that fluctuates rapidly by repeating peak-to-peak. a first depth-hold section that obtains the minimum amplitude ratio, which is the minimum value of the ratio; a peak-hold section that obtains the envelope of the peak that connects the upper end of the peak of the amplitude ratio for acoustic coupling measurement; a second depth hold section that calculates a minimum peak value that is a value; a threshold calculation section that sets a threshold value from the minimum amplitude ratio and the minimum peak value; and a threshold calculation section that sets a threshold value from the minimum amplitude ratio and the minimum peak value; a transmitting/receiving determination unit that compares the amplitude ratio for transmitting/receiving determination, and determines that the transmitting/receiving determination amplitude ratio is larger than the threshold value, and determining that the received call is received when the amplitude ratio is smaller than the threshold, and sends the determination result to the receiving/receiving attenuator and the transmitting/receiving attenuator. It is composed of.
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。Effect: With this configuration, the magnitude of acoustic coupling in the echo path from the speaker to the microphone can be constantly measured, and a threshold value commensurate with this measured value can be automatically set. Therefore, it is possible to always perform transmission/reception judgment with high sensitivity and without false detection, and it is possible to perform two-way communication without howling or disconnection at the beginning of a conversation.
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。EXAMPLE An example of the present invention will be described below with reference to the drawings.
第１図において、１＋′ｉ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・ツブを繰り返して激し
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・ンブホールド部、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
デツプホールド部、１６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シ大きい場合に
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, 1+'i input terminal for receiving input signal, 2
3 is a speaker, 4 is a microphone, and 5 is a transmitting attenuation unit which attenuates the transmitting input signal output from the microphone 4 and outputting the transmitting output signal by attenuating the receiving input signal. 6 is an output terminal for a transmitting output signal;
Reference numeral 7 refers to a receiver input amplitude calculation unit that rectifies and smoothes the receiver input signal to calculate the amplitude of the receiver input signal, 8 refers to a receiver output amplitude calculator that rectifies and smoothes the receiver output signal to obtain the amplitude of the receiver output signal, and 9 indicates a transmitter. A transmitting input amplitude calculating section 10 calculates the amplitude of the transmitting input signal by rectifying and smoothing the input signal, and 10 is a first transmitting input amplitude calculating section that divides the amplitude of the transmitting input signal by the amplitude of the receiving input signal to obtain an amplitude ratio for transmitting/receiving determination. A dividing unit 11 is a second dividing unit that divides the amplitude of the transmitting output signal by the amplitude of the receiving input signal to obtain an amplitude ratio for acoustic coupling measurement. 13 is a peak hold unit that determines the envelope of the peak that connects the upper end of the peak of the amplitude ratio for acoustic coupling measurement; 14; 16 is a second depth hold unit that calculates a minimum peak value that is the minimum value of the envelope of this peak; 16 is a threshold calculation unit that sets a threshold value from the minimum amplitude ratio and the minimum peak value;
compares this threshold with the amplitude ratio for transmission/reception determination,
A transmission/reception determination section that determines that a call is being sent when the amplitude ratio for transmission/reception determination is larger than the threshold value, and a reception when it is smaller; In the transmitting state, the attenuation amount of the receiving attenuation section 2 is set high and the attenuation amount of the transmitting attenuation section 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 parts of the embodiment shown in FIG. 1, and the operation of the embodiment shown in FIG. 1 will be explained using this diagram.
第２図において、２１は第１図のＥ点の受話人力振幅の
波形、２２は第１図のＢ点の受話出力振幅の波形、２３
は０点の送話人力振幅の波形、２４はＤ点の送受判定用
振幅比の波形、２６はＥ点の音響結合測定用振幅比の波
形、２６１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、２６３はＨ点の最小ピーク値の
波形、２６は１点のしきい値の波形、２７は３点の判定
信号の波形、２ＢＦｉ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 the waveform of the receiver's human power amplitude at point E in FIG. 1, 22 is the waveform of the receiver's output amplitude at point B in FIG. 1, and 23
24 is the waveform of the amplitude ratio for transmission/reception determination at point D, 26 is the waveform of the amplitude ratio for acoustic coupling measurement at point E, 261 is the waveform of the minimum amplitude ratio at point F, 252 is the waveform of the peak envelope of point G, 263 is the waveform of the minimum peak value of point H, 26 is the waveform of the threshold value of 1 point, 27 is the waveform of the judgment signal of 3 points, and 2BFi reception attenuation unit 2 attenuation 29 shows how the amount of attenuation of the transmitting attenuator 5 changes.
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図の受話人力振
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、送話人力振幅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、送話人力振幅２３を受話人力振幅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、送話人力振幅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 receiving input signal, which is the voice signal of the far-end speaker, is rectified and smoothed by the receiving input amplitude calculation unit 7 shown in FIG. 1, and becomes the receiving human power amplitude 21 shown in FIG. On the other hand, this reception input signal passes through the reception attenuation section 2 shown in FIG. 1, becomes a reception output signal, and 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 collects the echoed sound from the speaker 3 and the voice of the near-end speaker speaking into the microphone 4, and outputs a transmission input signal. This transmitting input signal is rectified and smoothed by a transmitting input amplitude calculating section 9 to become a transmitting human power amplitude 23. On the other hand, this transmission input signal passes through the transmission attenuation section 5 and becomes a transmission output signal, which is output from the output terminal 6. In the first division unit 10, the transmitter's human force amplitude 23 is converted into the receiver's human force amplitude 22.
The amplitude ratio 25 for transmission/reception determination is obtained. The second dividing unit 9 divides the human power amplitude 24 of the transmitter by the output amplitude 23 of the receiver to obtain an amplitude ratio 25 for measuring acoustic coupling.
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
時刻で１〜Ｔ２では、この音響結合測定用ｆｆｉ幅比２
５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で３〜
で４では、送話人力振幅２３だけが上昇するため、音響
結合測定用振幅比２６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、時刻で１〜Ｔ２の音響結合測定用
振幅比２６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。At times 1 to T2 shown in FIG. 2 when only the far-end speaker is speaking and is in the receiving state, this ffi width ratio for acoustic coupling measurement is 2.
5 indicates the magnitude of acoustic coupling in the reverberant path consisting of a speaker and a microphone. 3~ at the time when the near-end speaker started speaking
In case 4, only the transmitting human power amplitude 23 increases, so the acoustic coupling measurement amplitude ratio 26 becomes a very large value. Therefore, it can be seen that in order to determine the magnitude of acoustic coupling in the echo path, it is sufficient to find the minimum value of this acoustic coupling measurement amplitude ratio 25. However, as can be seen from the acoustic coupling measurement amplitude ratio 26 from 1 to T2 at time, this acoustic coupling measurement amplitude ratio 25 fluctuates minutely.
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。The degree of this variation varies greatly depending on the characteristics of the echo path. Therefore, the minimum value of the acoustic coupling measurement amplitude ratio 25 cannot be taken as the magnitude of the acoustic coupling 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、第一のデツプホールド部１２で音響結合測定用振
幅比２６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２６はピークホールド部１
３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２６２を求める。次に第二
のデツプホールド部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２６３を求める。First, a minimum amplitude ratio signal 251, which is the minimum value of the acoustic coupling measurement amplitude ratio 26, is obtained in the first depth hold section 12. On the other hand, the amplitude ratio 26 for acoustic coupling measurement is
The envelope 262 of the peak connected to the upper end of the peak of the amplitude ratio 25 for acoustic coupling measurement which is also input to 3 is determined. Next, the second depth hold section 14 obtains a minimum peak value 263, which is the minimum value of the envelope 252 of this peak.
この最小振幅比２６１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２６１と最小ピーク値２６３とから次式に
より、しきい値２６を計算する。A detailed look at the minimum amplitude ratio 261 and the minimum peak value 253 reveals 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 value calculation unit 15 calculates the threshold value 26 from the minimum amplitude ratio 261 and the minimum peak value 263 using the following equation.
しきい値＝２傘最小ピーク値−最小振幅比・・・・・・
（１）
送受判定部１６では、このよってして求めたしきい値２
６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。Threshold = 2 Umbrella Minimum peak value - Minimum amplitude ratio...
(1) The transmission/reception determination unit 16 uses the threshold value 2 thus obtained.
6 and the amplitude ratio for sending/receiving judgment 24, when the amplitude ratio for sending/receiving judgment is above the threshold value, it is judged as sending, and when it is below, it is judged as receiving. Send to Section 5.
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６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６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６の
減衰量は２９に示すように制御される。The attenuation amounts of these two attenuation parts are controlled reciprocally,
When the attenuation amount of one becomes high, the attenuation amount of the other always becomes low. That is, in the receiving state, the amount of attenuation of the receiving attenuator 2 is small, and the amount of attenuation of the transmitting attenuator 6 is large. Conversely, in the transmitting state, the amount of attenuation of the receiving attenuator 2 is large and the amount of attenuation of the transmitting attenuator 6 is small. As described above, the attenuation amount of the receiving attenuator 2 is controlled as shown at 28, and the attenuation amount of the transmitting attenuator 6 is controlled as shown at 29.
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, it is possible to automatically set a threshold value that matches the acoustic coupling strength of the echo path from the value of the acoustic coupling measurement amplitude ratio. Therefore, voice switch operation with high sensitivity and less false detection is possible.
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ツプホールド部と、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ツプホールド部と
、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 provides a first depth hold section for determining the minimum amplitude ratio, which is the minimum value of the amplitude ratio for acoustic coupling measurement, and a peak holding section for determining the envelope of the peak connecting the upper end of the peak of the amplitude ratio for acoustic coupling measurement. a hold unit, a second depth hold unit that calculates a minimum peak value that is the minimum value of the envelope of this peak, and a threshold calculation unit that sets a threshold from the minimum amplitude ratio and the minimum peak value, It constitutes a threshold setting means, and accurately determines the acoustic coupling strength of the echo path from the amplitude ratio for acoustic coupling measurement, which fluctuates rapidly due to repeated peaks and dips, and automatically sets a threshold corresponding to this. Can be set.
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。In addition, when the acoustic coupling strength of the echo path is high, the threshold value can be set high, and when the acoustic coupling strength is low, the threshold value can be set automatically, so the sound sensitivity is always high and there is no false detection. 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
プロ・ツク図、第２図Ｖｉ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、１ｏ・・・・・・第一の除算部、１１・・・・・・
第二の除算部、１２・・・・・・第一のデツプホールド
部、１３・・・・・・ピークホールド部、１４・・・・
・・第二のデツプホールド部、１６・・・・・・しきい
値計算部、１６・・・・・・送受判定部。
代理人の氏名 弁理士 中 尾 敏 男 ほか１名−ｑ
コ
第２図
第 ３ 図FIG. 1 is a block diagram of an audio 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 audio switch circuit, The figure is a waveform diagram of signals at each part in FIG. 3. 2... Receiving voice attenuation section, 5... Sending voice attenuation section, 7... Receiving voice input amplitude calculation section, 8...
Receiving output amplitude calculating section, 9... Sending input amplitude calculating section, 1o... First dividing section, 11...
Second division section, 12...First depth hold section, 13...Peak hold section, 14...
. . . second depth hold section, 16 . . . threshold value calculation section, 16 . . . transmission/reception determination section. Name of agent: Patent attorney Toshio Nakao and 1 other person-q
Figure 2 Figure 3
Claims (1)
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。There is a receiving attenuation section that attenuates the receiving input signal to produce a receiving output signal, which has a small attenuation amount when receiving a call and a large attenuation amount when transmitting a call, and a receiving attenuation section that attenuates a receiving input signal to produce a receiving output signal, and a large attenuation amount when receiving a call, and a small attenuation amount when transmitting a call. a transmitting attenuator that attenuates a transmitting input signal to produce a transmitting output signal, a receiving input amplitude calculating section that calculates the amplitude of the receiving input signal, and a receiving output amplitude calculator that calculates the amplitude of the receiving output signal. a transmitting input amplitude calculation unit that calculates the amplitude of the transmitting input signal;
a first dividing unit that divides the amplitude of the transmitting input signal by the amplitude of the receiving input signal to obtain an amplitude ratio for transmitting/receiving determination; and dividing the amplitude of the transmitting input signal by the amplitude of the receiving output signal. A second divider section that calculates the amplitude ratio for acoustic coupling measurement and a peak
A first dep hold section that determines a minimum amplitude ratio that is the minimum value of the amplitude ratio for acoustic coupling measurement which fluctuates drastically by repeating the dip, and an envelope of the peak connecting the upper end of the peak of the amplitude ratio for acoustic coupling measurement. a peak hold unit that calculates the minimum peak value, which is the minimum value of the envelope of this peak, and a threshold calculation that sets a threshold value from the minimum amplitude ratio and the minimum peak value. This threshold value is compared with the amplitude ratio for transmitting/receiving determination, and if the amplitude ratio for transmitting/receiving determination is larger than the threshold, it is determined that the call is being transmitted, and if it is smaller than the threshold, it is determined that the call is being received. 1. A voice switch circuit comprising: a reception attenuation section; and a transmission/reception determination section that sends a signal to the transmission attenuation section.
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 true JPS63155938A (en) | 1988-06-29 |
| JPH0691579B2 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) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007315679A (en) * | 2006-05-25 | 2007-12-06 | Air Cycle Sangyo Kk | Ventilation device |
-
1986
- 1986-12-19 JP JP30432586A patent/JPH0691579B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007315679A (en) * | 2006-05-25 | 2007-12-06 | Air Cycle Sangyo Kk | Ventilation device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0691579B2 (en) | 1994-11-14 |
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