JPS6427325A - Echo canceller - Google Patents
Echo cancellerInfo
- Publication number
- JPS6427325A JPS6427325A JP18235787A JP18235787A JPS6427325A JP S6427325 A JPS6427325 A JP S6427325A JP 18235787 A JP18235787 A JP 18235787A JP 18235787 A JP18235787 A JP 18235787A JP S6427325 A JPS6427325 A JP S6427325A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- noise
- voice
- correlation coefficient
- circuit
- 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
Landscapes
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
PURPOSE:To improve the characteristic of an echo canceller by providing a correlation coefficient calculation section so as to obtain the correlation coefficient of a transmission side input signal from a 2-wire side to a 4-wire side, thereby deciding whether the signal is voice or noise and discriminating accurately the actual double talk state from the case with a large nearby noise. CONSTITUTION:A correlation coefficient calculation section 25 obtains a correlation coefficient of a transmission side input signal Sin outputted from a hybrid circuit 11 to a 4-wire side so as to decide whether the signal is voice or noise. When a double talk detection section 17 decides it as the double talk state, a deciding signal '1' is fed to a coefficient correction section 15 and an AND circuit 26. When the coefficient calculation section 25 decides noise, a noise deciding signal '1' is fed to an AND circuit 26. Thus, the attenuation of a variable attenuator 27 is increased by an output signal '1' of the AND circuit 26 and a transmission side output signal Sout is obtained, where the level of the echo residual signal including nearby end noise is reduced. Moreover, in case of the double talk state, when the section 25 decides voice, the attenuation of the variable attenuator 27 is kept zero, the voice signal is not attenuated but becomes the transmission side output signal Sout.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18235787A JPS6427325A (en) | 1987-07-23 | 1987-07-23 | Echo canceller |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP18235787A JPS6427325A (en) | 1987-07-23 | 1987-07-23 | Echo canceller |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS6427325A true JPS6427325A (en) | 1989-01-30 |
Family
ID=16116900
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP18235787A Pending JPS6427325A (en) | 1987-07-23 | 1987-07-23 | Echo canceller |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS6427325A (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5193112A (en) * | 1990-01-24 | 1993-03-09 | Nec Corporation | Arrangement and method for rapidly detecting double talk in long distance telephone communications system |
US6445792B1 (en) | 1996-04-25 | 2002-09-03 | Mitsubishi Denki Kabushiki Kaisha | Echo canceller for decreasing a deterioration factor of a speech quality |
JP2007231581A (en) * | 2006-02-28 | 2007-09-13 | Nippon Steel & Sumikin Coated Sheet Corp | Roof structure and method of constructing the same |
JP2008219088A (en) * | 2007-02-28 | 2008-09-18 | Oki Electric Ind Co Ltd | Echo canceler and echo cancellation method |
US8208623B2 (en) | 2006-11-21 | 2012-06-26 | Fujitsu Limited | Echo processing method and device |
-
1987
- 1987-07-23 JP JP18235787A patent/JPS6427325A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5193112A (en) * | 1990-01-24 | 1993-03-09 | Nec Corporation | Arrangement and method for rapidly detecting double talk in long distance telephone communications system |
US6445792B1 (en) | 1996-04-25 | 2002-09-03 | Mitsubishi Denki Kabushiki Kaisha | Echo canceller for decreasing a deterioration factor of a speech quality |
JP2007231581A (en) * | 2006-02-28 | 2007-09-13 | Nippon Steel & Sumikin Coated Sheet Corp | Roof structure and method of constructing the same |
US8208623B2 (en) | 2006-11-21 | 2012-06-26 | Fujitsu Limited | Echo processing method and device |
JP2008219088A (en) * | 2007-02-28 | 2008-09-18 | Oki Electric Ind Co Ltd | Echo canceler and echo cancellation method |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CA2139895A1 (en) | Residual Echo Elimination with Proportionate Noise Injection | |
CA2205926A1 (en) | Echo cancelling arrangements | |
CA2004379A1 (en) | Echo canceller with means for determining filter coefficients from autocorrelation and cross-correlation coefficients | |
EP0135843B1 (en) | Echo canceller systems | |
KR960032929A (en) | Adaptive echo cancellation used for echo suppression to reduce long or short duration echo | |
JPS6442929A (en) | All double data transmission tranceiver | |
EP1229709A3 (en) | Echo sound signal suppressing apparatus | |
JPS6427325A (en) | Echo canceller | |
US5982755A (en) | System and method for providing high terminal coupling loss in a handsfree terminal | |
JPS5742242A (en) | Two-wire type bidirectional amplifier system | |
JPS5735457A (en) | Loudspeaker telephone set system | |
JPS57114832A (en) | Deector for leakage of liquid transport pipeline | |
JPS54130819A (en) | Two-way variable gain amplifier | |
JPS645233A (en) | Echo canceller | |
JPS6016773B2 (en) | two way call detector | |
JPS57145500A (en) | Reverberation sound adder | |
JPS55135407A (en) | Sound volume adjustor for speaker | |
JPS6221457B2 (en) | ||
JPS573441A (en) | Echo eliminator | |
JPS6424660A (en) | Voice conference equipment | |
JPS57129033A (en) | Echo suppressor | |
JPS5787246A (en) | Echo canceller | |
JPS55118238A (en) | Adaptive type echo block unit | |
JPS5789337A (en) | Echo erasing device | |
JPH02146827A (en) | Echo canceler |