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Class Information
Number: 379/390.02
Name: Telephonic communications > Substation or terminal circuitry > For loudspeaking terminal > Amplification or attenuation level control > Filtering (fir, hpf, widrow-hoff, lms)
Description: Subject matter including circuitry for selectively allowing the passing through or blocking certain signals or frequencies.
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 7590419 |
Frequency correction channel burst detector in a GSM/EDGE communication system |
Sep. 15, 2009 |
| 7457405 |
Enhanced low pass filter |
Nov. 25, 2008 |
| 7352857 |
Method and apparatus for spectral containment over telephone service lines |
Apr. 1, 2008 |
| 7227944 |
Echo reduction for a headset or handset |
Jun. 5, 2007 |
| 7187765 |
Method of capturing constant echo path information in a full duplex speakerphone using default coefficients |
Mar. 6, 2007 |
| 7095846 |
Half duplex device and signal processing method thereof |
Aug. 22, 2006 |
| 7079646 |
ADSL receiver high pass filter architecture |
Jul. 18, 2006 |
| 7043013 |
Method for adaptive control of multichannel acoustic echo cancellation system and device therefor |
May. 9, 2006 |
| 7039179 |
Echo reduction for a headset or handset |
May. 2, 2006 |
| 7020275 |
Method and apparatus for spectral containment over telephone service lines |
Mar. 28, 2006 |
| 7003093 |
Tone detection for integrated telecommunications processing |
Feb. 21, 2006 |
| 6978011 |
Enhanced low pass filter |
Dec. 20, 2005 |
| 6975140 |
Adaptive data transmitter having rewriteable non-volatile storage |
Dec. 13, 2005 |
| 6928161 |
Echo cancellation apparatus, systems, and methods |
Aug. 9, 2005 |
| 6925177 |
Echo canceler compensating for amplifier saturation and echo amplification |
Aug. 2, 2005 |
| 6904146 |
Full duplex echo cancelling circuit |
Jun. 7, 2005 |
| 6898280 |
Line card and method for supporting pots, asymmetric DSL and symmetric DSL services |
May. 24, 2005 |
| 6888938 |
Dynamically adjustable digital gyrator having extendable feedback for stable DC load line |
May. 3, 2005 |
| 6845252 |
Programmable echo cancellation filter |
Jan. 18, 2005 |
| 6842517 |
Meter pulse filtering circuit for analog modems |
Jan. 11, 2005 |
| 6842516 |
Digital adaptive filter and acoustic echo canceller using the same |
Jan. 11, 2005 |
| 6836546 |
Apparatus and method of coupling home network signals between an analog phone line and a digital bus |
Dec. 28, 2004 |
| 6831975 |
Digital subscriber line (DSL) modem compatible with home networks |
Dec. 14, 2004 |
| 6795547 |
Full duplex speaker-phone providing increased loop stability |
Sep. 21, 2004 |
| 6792107 |
Double-talk detector suitable for a telephone-enabled PC |
Sep. 14, 2004 |
| 6751313 |
Method and apparatus for an improved echo canceller |
Jun. 15, 2004 |
| 6711260 |
Method and apparatus for spectral containment over telephone service lines |
Mar. 23, 2004 |
| 6691073 |
Adaptive state space signal separation, discrimination and recovery |
Feb. 10, 2004 |
| 6608898 |
Band pass and notch filters for echo reduction with less phase distortion |
Aug. 19, 2003 |
| 6570985 |
Echo canceler adaptive filter optimization |
May. 27, 2003 |
| 6553118 |
Method and apparatus for calculating DC offset in a digital gyrator |
Apr. 22, 2003 |
| 6044150 |
Method and apparatus for a host-based personal computer speakerphone |
Mar. 28, 2000 |
| 6009165 |
Full duplex speakerphone system |
Dec. 28, 1999 |
| 5999618 |
Telephone interface for simultaneous audio presentation at separate locations utilizing amplitude modulated carrier signals |
Dec. 7, 1999 |
| 5796818 |
Dynamic optimization of handsfree microphone gain |
Aug. 18, 1998 |
| 5774536 |
Balanced network for use in a keyphone system |
Jun. 30, 1998 |
| 5768398 |
Signal amplification system with automatic equalizer |
Jun. 16, 1998 |
| 5680450 |
Apparatus and method for canceling acoustic echoes including non-linear distortions in loudspeaker telephones |
Oct. 21, 1997 |
| 5664019 |
Systems for feedback cancellation in an audio interface garment |
Sep. 2, 1997 |
| 5644635 |
Method of and device for echo cancellation |
Jul. 1, 1997 |
| 5617472 |
Noise suppression of acoustic signal in telephone set |
Apr. 1, 1997 |
| 5555272 |
Signal processing device using several different filterings, especially for audio-frequency coding of voice signals |
Sep. 10, 1996 |
| 5533120 |
Acoustic feedback cancellation for equalized amplifying systems |
Jul. 2, 1996 |
| 5502717 |
Method and apparatus for estimating echo cancellation time |
Mar. 26, 1996 |
| 5410592 |
Class `D` audio speaker amplifier circuit with state variable feedback control |
Apr. 25, 1995 |
| 5406622 |
Outbound noise cancellation for telephonic handset |
Apr. 11, 1995 |
| 5398278 |
Digital musicians telephone interface |
Mar. 14, 1995 |
| 5379450 |
Radio loudspeaker telephone device capable of automatically preventing howling on execution of calling operation |
Jan. 3, 1995 |
| 5327494 |
Dial tone annunciating system and method |
Jul. 5, 1994 |
| 5323457 |
Circuit for suppressing white noise in received voice |
Jun. 21, 1994 |
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