JPS6318796A - Howling suppressing method - Google Patents
Howling suppressing methodInfo
- Publication number
- JPS6318796A JPS6318796A JP16089686A JP16089686A JPS6318796A JP S6318796 A JPS6318796 A JP S6318796A JP 16089686 A JP16089686 A JP 16089686A JP 16089686 A JP16089686 A JP 16089686A JP S6318796 A JPS6318796 A JP S6318796A
- Authority
- JP
- Japan
- Prior art keywords
- howling
- frequency
- microphone
- increasing ratio
- spectrum
- 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.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims description 9
- 238000001228 spectrum Methods 0.000 claims abstract description 28
- 238000001514 detection method Methods 0.000 abstract description 4
- 230000005540 biological transmission Effects 0.000 abstract 1
- 230000005236 sound signal Effects 0.000 description 5
- 230000001629 suppression Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 3
- 230000003321 amplification Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
Landscapes
- Circuit For Audible Band Transducer (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は、拡声装置等に利用するハウリング抑圧方法に
関するものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a howling suppression method used in a public address system or the like.
(従来の技術)
第2図は従来のハウリング抑圧方法を実施する装置のブ
ロック構成を示している。第2図におり)て、マイクロ
ホン20はエコーキャンセラ21に接続されており、エ
コーキャンセラ21は増幅器22に接続されている。2
3はホワイトノイズの発生装置である。24はスイッチ
であり、増幅器22とホワイトノイズ発生装置23との
両方に接続されている。25はスピーカであり、エコー
キャンセラ21とスイッチ24との両方に接続されてい
る。(Prior Art) FIG. 2 shows a block configuration of a device that implements a conventional howling suppression method. In FIG. 2), the microphone 20 is connected to an echo canceller 21, and the echo canceller 21 is connected to an amplifier 22. 2
3 is a white noise generator. 24 is a switch, which is connected to both the amplifier 22 and the white noise generator 23. 25 is a speaker, which is connected to both the echo canceller 21 and the switch 24.
次に、上記従来例の動作について説明する。第2図にお
いて、スイッチ24によりホワイトノイズ発生装置23
を選択すると、ホワイトノイズをスピーカ25から出力
し、マイクロホン20で受音し、仝ツーキャンセラ21
を動作させて、スピーカ25からマイクロホン20への
伝達特性を予め推定させる。Next, the operation of the above conventional example will be explained. In FIG. 2, the white noise generator 23 is activated by the switch 24.
When you select , white noise is output from the speaker 25, received by the microphone 20, and transmitted to the two-canceller 21.
is operated to estimate the transfer characteristics from the speaker 25 to the microphone 20 in advance.
その後、スイッチ24の選択で増i器22の出力信号を
スピーカから出力させる。Thereafter, by selecting the switch 24, the output signal of the i-multiplier 22 is outputted from the speaker.
このように、上記従来のハウリング抑圧方法でも、予め
スピーカからマイクロホンまでの伝達特性を推定すると
、ハウリング抑圧することができる。In this way, howling can be suppressed even in the conventional method for suppressing howling by estimating the transfer characteristics from the speaker to the microphone in advance.
(発明が解決しようとする問題点) しかしながら、上記従来のハウリング方法では。(Problem that the invention attempts to solve) However, in the conventional howling method described above.
予めスピーカからマイクロホンへの伝達特性を推定する
ため、推定をした後で伝達特性が変わると、ハウリング
を抑圧することができないという問題があった。Since the transfer characteristics from the speaker to the microphone are estimated in advance, there is a problem in that if the transfer characteristics change after the estimation, howling cannot be suppressed.
本発明は、このような従来の問題を解決するものであり
、適応的にハウリングを抑圧できる優れたハウリング抑
圧方法を提供することを目的とするものである。The present invention is intended to solve such conventional problems, and aims to provide an excellent howling suppression method that can adaptively suppress howling.
(問題点を解決するための手段)
本発明は上記目的を達成するために、マイクロホンの受
音信号に対して高速フーリエ変換(FFT)を行い、そ
こで得られたスペクトルの振幅情報によって、各スペク
トルの増加率と、全スペクトルの平均増加率とを調べ、
平均増加率よりも大きな増加率を示し、その状態が連続
している周波数でハウリングが発生するとみなし、その
周波数の成分を小さくすることを特徴とする。(Means for Solving the Problems) In order to achieve the above object, the present invention performs fast Fourier transform (FFT) on a sound signal received by a microphone, and uses the amplitude information of the spectrum obtained thereby to transform each spectrum. and the average increase rate of all spectra,
It is characterized in that it is assumed that howling occurs at a frequency that exhibits a larger rate of increase than the average rate of increase and continues in that state, and that the components of that frequency are reduced.
(作 用)
本発明は上記のような構成であり、本発明によれば、マ
イクロホンの受音信号のスペクトルの増力η率を調べて
全スペクトルの平均増加率よりも大きな状態の続いてい
る周波数を検出する。そして。(Function) The present invention has the above-described configuration, and according to the present invention, the amplification η rate of the spectrum of the sound signal received by the microphone is checked, and the frequencies at which the increase rate continues to be larger than the average increase rate of the entire spectrum are determined. Detect. and.
その周波数の利得を下げることで、適応的にハウリング
を抑圧することができる効果を有する。By lowering the gain of that frequency, it has the effect of adaptively suppressing howling.
(実施例)
第1図は、本発明の方法を実施するための装置の構成の
一例を示している0本装置はマイクロホン10と、マイ
クロホン10の受音信号をスペクトル分解するFFT回
路11と、各スペクトルからハウリングを検出するハウ
リング検出回路12と、ハウリングの発生した周波数の
利得を下げるイコライザ回路13と、増幅器14と、ス
ピーカ15とを備えたものである。(Example) FIG. 1 shows an example of the configuration of an apparatus for carrying out the method of the present invention. This apparatus includes a microphone 10, an FFT circuit 11 that spectrally decomposes a sound signal received by the microphone 10, The system includes a howling detection circuit 12 that detects howling from each spectrum, an equalizer circuit 13 that reduces the gain of the frequency at which howling occurs, an amplifier 14, and a speaker 15.
次に、上記実施例の動・作について説明する。第1図に
おいて、マイクロホンlOの受音信号を、FFT回路1
1により、各スペクトルFi(i=l〜N)の大きさに
変換する。ハウリング検出回路12では、各スペクトル
Fiの前回のスペクトルからの増加率を調べる。そして
、すべてのスペクトルの平均増加率を求める0次に、各
スペクトルの増加率と、平均増加率とを比較して、平均
増加率をあるレベルより大きく上まわっているスペクト
ルを検出し、その状態がM回連続していたら、その周波
数でハウリングが発生していると判断して。Next, the operation of the above embodiment will be explained. In FIG. 1, the sound reception signal of the microphone IO is converted into
1 to convert the magnitude of each spectrum Fi (i=l to N). The howling detection circuit 12 examines the rate of increase of each spectrum Fi from the previous spectrum. Next, the average increase rate of all spectra is calculated. Next, the increase rate of each spectrum is compared with the average increase rate, and a spectrum whose average increase rate is much higher than a certain level is detected, and its state is If this occurs M times in a row, it is determined that howling is occurring at that frequency.
その周波数での利得を下げるようにイコライザを自動調
節する。これを第3図を用いて説明すると、第3図(a
)から第3図(b)、あるいは第3図(c)にスペクト
ルが変化した時は、ハウリングとは考えず、入力信号が
変化したか、増幅器の増幅率が変化したと考える。しか
し、第3図(a)から第3図(d′)に変化した時は、
図の左から3番目のスペクトルは平均増加率よりも大き
な増加率を示して□いるので、この状態が連続して生じ
るときハウリングと考える。Automatically adjusts the equalizer to reduce the gain at that frequency. To explain this using Figure 3, Figure 3 (a
) to Fig. 3(b) or Fig. 3(c), do not consider this to be howling, but consider that the input signal has changed or the amplification factor of the amplifier has changed. However, when changing from Figure 3(a) to Figure 3(d'),
Since the third spectrum from the left in the figure shows an increase rate larger than the average increase rate, it is considered howling when this state occurs continuously.
上記実施例によると、マイクロホンの受音信号のスペク
トルを常時観測して、全スペクトルの平均増加率よりも
、増加率の大きな状態が続いているスペクトルを減衰さ
せるため、スピーカからマイクロホンへの回り込みの伝
達関数の変化にも追従でき、適応的にハウリングを抑圧
できる効果が為る。According to the above embodiment, the spectrum of the sound signal received by the microphone is constantly observed, and in order to attenuate the spectrum in which the increase rate continues to be larger than the average increase rate of all spectra, the feedback from the speaker to the microphone is reduced. It can also follow changes in the transfer function and has the effect of adaptively suppressing howling.
(発明の効果)
本発明は、全スペクトルの平均増加率よりも、増加率の
大きな状態が続いている周波数をハウリング発生周波数
とみなし、その周波数の利得を下げることで、スピーカ
とマイクロホンの間の伝達関数の振幅特性の補正を行い
、適応的にハウリングを抑圧することができる。(Effects of the Invention) The present invention regards a frequency where the increase rate continues to be larger than the average increase rate of the entire spectrum as the howling generation frequency, and lowers the gain of that frequency, thereby increasing the frequency between the speaker and the microphone. Howling can be adaptively suppressed by correcting the amplitude characteristics of the transfer function.
第1図は本発明の一実施例におけるハウリング抑圧方法
のブロック図、第2図は従来のハウリング抑圧方法のブ
ロック図である。第3図はマイクロホンの受音信号のス
ペクトルを示したものである。
lO・・・マイクロホン、11・・・FFT回路、12
・・・ハウリング検出回路、13・・・イコライザ回路
、 14・・・増幅器、 15・・・スピーカ。
20・・・マイクロホン、 21・・・エコーキャンセ
ラ、 22・・・増幅器、 23・・・ホワイトノイズ
発生装置、24・・・スイッチ、 25・・・スビー力
。
特許出願人 松下電器産業株式会社
第1図
第3
(C)
(b)
(d)FIG. 1 is a block diagram of a howling suppression method according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional howling suppression method. FIG. 3 shows the spectrum of the sound signal received by the microphone. lO...Microphone, 11...FFT circuit, 12
...Howling detection circuit, 13...Equalizer circuit, 14...Amplifier, 15...Speaker. 20...Microphone, 21...Echo canceller, 22...Amplifier, 23...White noise generator, 24...Switch, 25...Subey power. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1, No. 3 (C) (b) (d)
Claims (1)
い、そこで得られたスペクトルの振幅情報によって、各
スペクトルの増加率と、全スペクトルの平均増加率とを
調べ、平均増加率よりも大きな増加率を示し、その状態
が連続している周波数でハウリングが発生するとみなし
、その周波数の成分を小さくすることを特徴とするハウ
リング抑圧方法。Fast Fourier transform is performed on the signal received by the microphone, and the increase rate of each spectrum and the average increase rate of all spectra are investigated using the amplitude information of the spectrum obtained. 1. A method for suppressing howling, which assumes that howling occurs at a frequency where the state is continuous, and reduces the component of that frequency.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16089686A JPS6318796A (en) | 1986-07-10 | 1986-07-10 | Howling suppressing method |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP16089686A JPS6318796A (en) | 1986-07-10 | 1986-07-10 | Howling suppressing method |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS6318796A true JPS6318796A (en) | 1988-01-26 |
Family
ID=15724700
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP16089686A Pending JPS6318796A (en) | 1986-07-10 | 1986-07-10 | Howling suppressing method |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6318796A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02143700A (en) * | 1988-11-25 | 1990-06-01 | Toshiba Corp | Howling preventing device |
EP0486679A1 (en) * | 1990-06-13 | 1992-05-27 | Sabine Musical Manufacturing C | Method and apparatus for adaptive audio resonant frequency filtering. |
US5206913A (en) * | 1991-02-15 | 1993-04-27 | Lectrosonics, Inc. | Method and apparatus for logic controlled microphone equalization |
EP0599450A2 (en) * | 1992-11-25 | 1994-06-01 | Matsushita Electric Industrial Co., Ltd. | Sound amplifying apparatus with automatic howl-suppressing function |
DK200970303A (en) * | 2009-12-29 | 2011-06-30 | Gn Resound As | A method for the detection of whistling in an audio system and a hearing aid executing the method |
-
1986
- 1986-07-10 JP JP16089686A patent/JPS6318796A/en active Pending
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH02143700A (en) * | 1988-11-25 | 1990-06-01 | Toshiba Corp | Howling preventing device |
EP0486679A1 (en) * | 1990-06-13 | 1992-05-27 | Sabine Musical Manufacturing C | Method and apparatus for adaptive audio resonant frequency filtering. |
US5206913A (en) * | 1991-02-15 | 1993-04-27 | Lectrosonics, Inc. | Method and apparatus for logic controlled microphone equalization |
EP0599450A2 (en) * | 1992-11-25 | 1994-06-01 | Matsushita Electric Industrial Co., Ltd. | Sound amplifying apparatus with automatic howl-suppressing function |
EP0599450A3 (en) * | 1992-11-25 | 1994-11-17 | Matsushita Electric Ind Co Ltd | Sound amplifying apparatus with automatic howl-suppressing function. |
US5442712A (en) * | 1992-11-25 | 1995-08-15 | Matsushita Electric Industrial Co., Ltd. | Sound amplifying apparatus with automatic howl-suppressing function |
DK200970303A (en) * | 2009-12-29 | 2011-06-30 | Gn Resound As | A method for the detection of whistling in an audio system and a hearing aid executing the method |
EP2355548A3 (en) * | 2009-12-29 | 2011-09-21 | GN ReSound A/S | A method for the detection of whistling in an audio system |
US8477976B2 (en) | 2009-12-29 | 2013-07-02 | Gn Resound A/S | Method for the detection of whistling in an audio system |
US9794695B2 (en) | 2009-12-29 | 2017-10-17 | Gn Hearing A/S | Detection of whistling in an audio system |
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