公开(公告)号：BR9305647A

公开(公告)日：1996-12-24

申请号：BR9305647

申请日：1993-09-24

Applicant: QUALCOMM INC

Inventor： SIH GILBERT C

IPC: H04M1/60 ,  G10L19/012 ,  H04B3/23 ,  H04M9/08

Abstract: An echo canceller and method for cancelling in a return channel signal an echoed receive channel signal where the echoed receive channel signal is combined by an echo channel with an input return channel signal. The echo canceller has a first filter which generates first filter coefficients, generates a first echo estimate signal with the first filter coefficients, and updates the first filter coefficients in response to a first filter control signal. A first summer subtracts the first echo estimate signal from a combined return channel and echo receive channel signal to generate a first echo residual signal. A second filter generates second filter coefficients, generates a second echo estimate signal with the second filter coefficients, and updates the second filter coefficients in response to a second filter control signal. A second summer subtracts the second echo estimate signal from the combined signal to generate a second echo residual signal, and provides upon the return channel the second echo residual signal. A control unit determines from the receive channel signal, the combined signal, and the first and second echo residual signals, one of a plurality of control states wherein a first control state is indicative of a receive channel signal above a first predetermined energy level, wherein when the control unit is in the first control state it generates the first control signal and generates the second control signal when at least one of a first energy ratio of the first echo residual signal and the combined signal and a second energy ratio of the second echo residual signal and the combined signal exceed a predetermined level.

公开(公告)号：BR9407935A

公开(公告)日：1996-11-26

申请号：BR9407935

申请日：1994-10-27

Applicant: QUALCOMM INC

Inventor： SIH GILBERT C ,  ANTONIO FRANKLIN P

IPC: H03H21/00 ,  H04B3/23

Abstract: An apparatus that automatically adjusts the adaptation block size for a least-mean square (LMS) adaptive filter depending on the input signal-to-noise ratio (SNR) is disclosed. The apparatus monitors the instantaneous SNR and continually adjusts the block size to provide high noise immunity, thereby increasing the convergence speed of the filter and decreasing the asymptotic mean-square error. An exemplary embodiment of the present invention is presented in the context of acoustic echo cancellation, though it is noted that the adaptive filter of the present invention is useful in any environment in which the noise characteristics are subject to change.

公开(公告)号：FI961824A0

公开(公告)日：1996-04-29

申请号：FI961824

申请日：1996-04-29

Applicant: QUALCOMM INC

Inventor： SIH GILBERT C ,  ANTONIO FRANKLIN P

IPC: H03H21/00 ,  H04B3/23 ,  H04B

Abstract: An apparatus that automatically adjusts the adaptation block size for a least-mean square (LMS) adaptive filter depending on the input signal-to-noise ratio (SNR) is disclosed. The apparatus monitors the instantaneous SNR and continually adjusts the block size to provide high noise immunity, thereby increasing the convergence speed of the filter and decreasing the asymptotic mean-square error. An exemplary embodiment of the present invention is presented in the context of acoustic echo cancellation, though it is noted that the adaptive filter of the present invention is useful in any environment in which the noise characteristics are subject to change.

公开(公告)号：BG98780A

公开(公告)日：1995-08-28

申请号：BG9878094

申请日：1994-05-18

Applicant: QUALCOMM INC

Inventor： SIH GILBERT C

IPC: H04M1/60 ,  G10L19/012 ,  H04B3/23 ,  H04M9/08

Abstract: The system can be applied in the field of communications engineering, and in particular in digital telephone systems. It guarantees high degree of dynamic echo neutralization including when a digital communication system is connected to an analogue one, and when calls are simultaneously conducted on both sides of the line. The channel signal produced as an echo is combined with an input reverse channel signal by an echochannel (142). The echo compensator contains first filter (156) which renews first filter coefficients in response to the first control filter signal; first adder (148) which generates first echo-residual signal; second filter (158) which renews second filter coefficients in response of second control filter signal; second adder (150) which generates second echo-residual signal, and control unit (152) determining one of the multiple control states the first control state is an indicative for receiving channel signal above the preset first energy level. In the first control state, the control unit (152) generates first control signal. The second control signal is generated when the preset level has been exceeded in at least one first energy degree of the first echo-residual signal and the combined signal or in a second energy degree of the second echo-residual signal and the combined signal.

公开(公告)号：AU8096294A

公开(公告)日：1995-05-23

申请号：AU8096294

申请日：1994-10-27

Applicant: QUALCOMM INC

Inventor： SIH GILBERT C ,  ANTONIO FRANKLIN P

IPC: H03H21/00 ,  H04B3/23

Abstract: An apparatus that automatically adjusts the adaptation block size for a least-mean square (LMS) adaptive filter depending on the input signal-to-noise ratio (SNR) is disclosed. The apparatus monitors the instantaneous SNR and continually adjusts the block size to provide high noise immunity, thereby increasing the convergence speed of the filter and decreasing the asymptotic mean-square error. An exemplary embodiment of the present invention is presented in the context of acoustic echo cancellation, though it is noted that the adaptive filter of the present invention is useful in any environment in which the noise characteristics are subject to change.

公开(公告)号：CA2723046C

公开(公告)日：2013-02-19

申请号：CA2723046

申请日：2002-02-15

Applicant: QUALCOMM INC

Inventor： LI TAO ,  HOLENSTEIN CHRISTIAN ,  KANG INYUP ,  WALKER BRETT C ,  PETERZELL PAUL E ,  CHALLA RAGHU ,  SEVERSON MATTHEW L ,  RAGHUPATHY ARUN ,  SIH GILBERT C

IPC: H03G1/00 ,  H04B1/16 ,  H03G3/00 ,  H03G3/20 ,  H03G3/30 ,  H04B1/30 ,  H04J13/00 ,  H04L27/22 ,  H04L27/38

Abstract: A direct downconversion receiver architecture having a DC loop to remove DC offset from the signal components, a digital variable gain amplifier (DVGA) to provide a range of gains, an automatic gain control (AGC) loop to provide gain control for the DVGA and RF/analog circuitry, and a serial bus interface (SBI) unit to provide controls for the RF/analog circuitry via a serial bus. The DVGA may be advantageously designed and located as described herein. The operating mode of the VGA loop may be selected based on the operating mode of the DC loop, since these two loops interact with one another. The duration of time the DC loop is operated in an acquisition mode may be selected to be inversely proportional to the DC loop bandwidth in the acquisition mode. The controls for some or all of the RF/analog circuitry may be provided via the serial bus.

公开(公告)号：CA2324219C

公开(公告)日：2011-05-10

申请号：CA2324219

申请日：1999-03-04

Applicant: QUALCOMM INC

Inventor： SIH GILBERT C ,  ZOU QUIZHEN ,  JHA SANJAY K ,  LIN JIAN ,  MOTIWALA QUAEED ,  JOHN DEEPU ,  ZHANG LI ,  ZHANG HAITAO ,  LEE WAY-SHING ,  SAKAMAKI CHARLES E ,  KANTAK PRASHANT A ,  KANG INYUP

IPC: G06F9/30 ,  G06F9/32 ,  G06F9/38 ,  G06F12/08 ,  G06F12/0886 ,  G06F15/78

Abstract: A circuit for digital signal processing calls for the use of a variable length instruction set. An exemplary DSP includes a set of three data buses (108, 110, 112) over which data may be exchanged with a register bank (120) and three data memories (102, 103, 104). A register bank (120) may be used that has registers accessible by at least two processing units (128, 130). An instruction fetch unit (156) may be included that receives instructions of variable length stored in an instruction memory (152). The instruction memory (152) may be separate from the set of three data memories (102, 103, 104).

公开(公告)号：DE69839260T2

公开(公告)日：2009-04-16

申请号：DE69839260

申请日：1998-01-27

Applicant: QUALCOMM INC

Inventor： SIH GILBERT C ,  MAURO ANTHONY P

IPC: H04B3/23 ,  H04M1/60 ,  H04B3/20 ,  H04M9/08

Abstract: A method and apparatus for controlling various functional elements in a digital telephone system using state determination from an echo canceller. An echo canceller is used to evaluate which one of five talk states two speakers are engaged in during a telephone conversation. This state determination information is used to control a tone detector function, a noise suppressor function, an adaptive equalizer function, a transmission mute function, and a vocoder encoder function within a vocoder. During the talk state where the far-end speaker is active and the near-end speaker is inactive, the echo canceller provides a signal which disables background noise estimates from being performed in the noise suppressor and the vocoder encoder. The same signal is used to disable the tone detector and to enable the transmission mute function during this talk state.

公开(公告)号：CA2343741C

公开(公告)日：2009-01-13

申请号：CA2343741

申请日：1999-09-03

Applicant: QUALCOMM INC

Inventor： ZOU QUIZHEN ,  SIH GILBERT C

IPC: G01S19/03 ,  G01S1/00 ,  G01S19/48 ,  H04Q7/34 ,  H04W64/00

Abstract: The present invention is a novel and improved method and apparatus for performing position location in wireless communications system. One embodiment of the invention comprises a method of performing position location in a wireless subscriber unit having a local oscillator, including the steps of receiving a position location request, acquiring a timing signal when a sufficient period of time has elapsed since the local oscillator has been corrected and correcting said local oscillator using a correction signal based on said timing signal, substantially freezing the connection signal, performing a position location procedure using the local oscillator with the correction signal applied, and ending said position location procedure.

公开(公告)号：DE69637266T2

公开(公告)日：2008-06-26

申请号：DE69637266

申请日：1996-05-31

Applicant: QUALCOMM INC

Inventor： SIH GILBERT C

IPC: H03H21/00 ,  H04B3/23 ,  H04M1/00 ,  H04Q3/42

Abstract: A system and method for detecting convergence in an echo canceller prevent false convergence from occurring as a result of receiving only tones in an input signal. An adaptive filter is used in an echo canceller to estimate an echo signal produced by an unknown echo channel. The estimated echo signal is subtracted from the return signal to remove the echo produced by the unknown echo channel. To prevent the echo canceller from falsely converging on a signal which contains only tones a system and method are provided for detecting the presence of tones in the absence of other frequencies. Filter taps of the adaptive filter are filtered to produce a filtered signal. The amount of energy in the filtered signal is compared to the amount of energy in the unfiltered filter taps to determine whether only tones have been present. If only tones have been present, the echo canceller is not allowed to reduce the adaptation step size of the adaptive filter.