US Patent No: 6,473,409

Number of patents in Portfolio can not be more than 2000

Adaptive filtering system and method for adaptively canceling echoes and reducing noise in digital signals

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Abstract

The present invention is embodied in a system and method for performing spectral analysis of a digital signal having a discrete duration by spectrally decomposing the digital signal at predefined frequencies uniformly distributed over a sampling frequency interval into complex frequency coefficients so that magnitude and phase information at each frequency is immediately available to produce a modulated complex lapped transform (MCLT). The system includes real and imaginary window processors and real and imaginary transform processors. The real and imaginary window processors receive the input signal and apply and compute butterfly coefficients for the real and imaginary parts of the signal to produce resulting real and imaginary vectors, respectively. The real and imaginary transform processors compute spatial transforms on the real and imaginary vectors to produce real and imaginary transform coefficient of the MCLT, respectively. The MCLT is a biorthogonal spectral transformation system, in the sense that the original time domain signal can be reconstructed exactly by an inverse MCLT operator.

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First Claim

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Patent Owner(s)

Patent OwnerAddressTotal Patents
MICROSOFT CORPORATIONREDMOND, WA24226

International Classification(s)

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  • [Patents Count]

Inventor(s)

Inventor Name Address # of filed Patents Total Citations
Malvar, Henrique S Sammamish, WA 114 1721

Cited Art

Patent Info (Count) # Cites Year
 
AEROSPACE CORPORATION, THE (1)
5,859,788 Modulated lapped transform method 41 1997
 
ERICSSON INC. (1)
6,163,608 Methods and apparatus for providing comfort noise in communications systems 73 1998
 
LUCENT TECHNOLOGIES INC. (1)
5,566,167 Subband echo canceler 44 1995
 
NIPPON TELEGRAPH AND TELEPHONE CORPORATION (1)
5,761,318 Method and apparatus for multi-channel acoustic echo cancellation 21 1996
 
ROCKSTAR BIDCO, LP (1)
6,108,413 Echo cancellation method and echo canceller implementing such a process 16 1998
 
TELEFONAKTIEBOLAGET LM ERICSSON (PUBL) (1)
5,793,801 Frequency domain signal reconstruction compensating for phase adjustments to a sampling signal 132 1996
 
TQ DELTA, LLC (1)
5,497,398 Multi-carrier transceiver 72 1993
 
UNIVERSITY OF MARYLAND, BALTIMORE (1)
5,339,265 Optimal unified architectures for the real-time computation of time-recursive discrete sinusoidal transforms 18 1992

Patent Citation Ranking

Forward Cites

Patent Info (Count) # Cites Year
 
MICROSOFT CORPORATION (28)
7,062,445 Quantization loop with heuristic approach 28 2001
7,206,453 Dynamic filtering for lossy compression 2 2001
7,120,197 Motion compensation loop with filtering 6 2002
7,609,763 Advanced bi-directional predictive coding of video frames 2 2003
7,383,180 Constant bitrate media encoding techniques 9 2003
7,343,291 Multi-pass variable bitrate media encoding 26 2003
7,251,322 Systems and methods for echo cancellation with arbitrary playback sampling rates 2 2004
7,590,179 Bitplane coding of prediction mode information in bi-directionally predicted interlaced pictures 1 2004
7,299,175 Normalizing to compensate for block size variation when computing control parameter values for quality and rate control for digital audio 11 2005
7,295,973 Quality control quantization loop and bitrate control quantization loop for quality and rate control for digital audio 10 2005
7,283,952 Correcting model bias during quality and rate control for digital audio 10 2005
7,277,848 Measuring and using reliability of complexity estimates during quality and rate control for digital audio 10 2005
7,263,482 Accounting for non-monotonicity of quality as a function of quantization in quality and rate control for digital audio 18 2005
7,260,525 Filtering of control parameters in quality and rate control for digital audio 18 2005
7,340,394 Using quality and bit count parameters in quality and rate control for digital audio 3 2005
7,200,276 Rate allocation for mixed content video 2 2005
7,295,971 Accounting for non-monotonicity of quality as a function of quantization in quality and rate control for digital audio 10 2006
8,238,424 Complexity-based adaptive preprocessing for multiple-pass video compression 0 2007
8,254,455 Computing collocated macroblock information for direct mode macroblocks 0 2007
7,644,002 Multi-pass variable bitrate media encoding 1 2007
8,160,132 Reducing key picture popping effects in video 0 2008
8,325,800 Encoding streaming media as a high bit rate layer, a low bit rate layer, and one or more intermediate bit rate layers 0 2008
8,379,851 Optimized client side rate control and indexed file layout for streaming media 0 2008
8,370,887 Media streaming with enhanced seek operation 0 2008
7,949,775 Stream selection for enhanced media streaming 0 2008
7,925,774 Media streaming using an index file 1 2008
8,265,140 Fine-grained client-side control of scalable media delivery 0 2008
8,189,666 Local picture identifier and computation of co-located information 0 2009
 
PANASONIC CORPORATION (8)
7,164,724 Communication apparatus 3 2003
7,760,810 Receiver and method for digital multi carrier transmission 0 2004
7,526,044 Transmitter and method for digital multi-carrier transmission 2 2004
7,529,308 Communication apparatus and communication method using digital wavelet multi carrier transmission system 3 2005
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7,590,185 Communication apparatus 1 2006
7,561,614 Communication apparatus and communication method using digital wavelet multi carrier transmission system 2 2008
8,189,698 Communication apparatus 0 2008
 
QNX SOFTWARE SYSTEMS LIMITED (8)
7,680,652 Periodic signal enhancement system 2 2004
8,170,879 Periodic signal enhancement system 0 2005
7,610,196 Periodic signal enhancement system 2 2005
7,949,520 Adaptive filter pitch extraction 4 2005
7,716,046 Advanced periodic signal enhancement 5 2005
8,306,821 Sub-band periodic signal enhancement system 0 2007
8,209,514 Media processing system having resource partitioning 0 2009
8,150,682 Adaptive filter pitch extraction 1 2011
 
STARKEY LABORATORIES, INC. (2)
7,542,580 Microphone placement in hearing assistance devices to provide controlled directivity 2 2006
7,809,149 Microphone placement in hearing assistance devices to provide controlled directivity 0 2009
 
THOMSON LICENSING (2)
7,292,638 Transform-based alias cancellation multi-channel tuner 1 2003
7,054,281 Multi-channel tuner using a discrete cosine transform 6 2003
 
NEC CORPORATION (1)
6,580,794 Acoustic echo canceler with a peak impulse response detector 4 1999
 
STMICROELECTRONICS N.V. (1)
8,045,703 Apparatus and method for echo-cancellation 0 2003

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