公开(公告)号：EP0829147B1

公开(公告)日：2007-09-26

申请号：EP96916826.9

申请日：1996-05-31

Applicant: QUALCOMM INCORPORATED

Inventor： SIH, Gilbert C.

IPC: H04B3/23

CPC classification number: H04B3/23

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 (304) is used in an echo canceller (300) to estimate an echo signal produced by an unknown echo channel (360). The estimated echo signal (328) is subtracted from the return signal (324) to remove the echo (362) produced by the unknown echo channel (360). To prevent the echo canceller (300) 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 (304) 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.

公开(公告)号：EP1454494B1

公开(公告)日：2018-09-26

申请号：EP02784710.2

申请日：2002-12-03

Applicant: QUALCOMM INCORPORATED

Inventor： SIH, Gilbert C. ,  TIAN, Yushi

IPC: H04N19/43 ,  H04N19/423

CPC classification number: H04N19/423 ,  H04N19/43 ,  H04N19/503 ,  H04N19/61

Abstract: In general, the invention is directed toward a device for processing digital video data, such as an encoder, a decoder or an encoder/decoder (CODEC). The device makes use of an innovative architecture in which functionality is partitioned between an embedded processor, a digital signal processor and dedicated hardware to achieve increased performance. In addition, the device includes a programmable video direct memory access (VDMA) controller to retrieve video data from memory in response to a command specifying a multidimensional block of video data.

公开(公告)号：EP1402631B1

公开(公告)日：2011-05-18

申请号：EP02709570.2

申请日：2002-02-15

Applicant: QUALCOMM INCORPORATED

Inventor： LI, Tao ,  HOLENSTEIN, Christian ,  KANG, Injup ,  WALKER, Brett, C. ,  PETERZELL, Paul, E. ,  CHALLA, Raghu ,  SEVERSON, Matthew, L. ,  RAGHUPATHY, Arun ,  SIH, Gilbert C.

IPC: H03G3/30 ,  H03D3/00 ,  H04B1/40

CPC classification number: H03G3/3078 ,  H03G3/3068 ,  H03G3/3089

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：EP0829147A1

公开(公告)日：1998-03-18

申请号：EP96916826.0

申请日：1996-05-31

Applicant: QUALCOMM INCORPORATED

Inventor： SIH, Gilbert C.

IPC: H03H21 ,  H04B3 ,  H04M1 ,  H04Q3

CPC classification number: H04B3/23

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 (304) is used in an echo canceller (300) to estimate an echo signal produced by an unknown echo channel (360). The estimated echo signal (328) is subtracted from the return signal (324) to remove the echo (362) produced by the unknown echo channel (360). To prevent the echo canceller (300) 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 (304) 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.