The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 15, 1996
Filed:
Jan. 04, 1995
Donald L Duttweiler, Rumson, NJ (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
Failure to cancel echos at frequencies in which the frequency characteristics of sub-band filters in the X and Y analysis filter banks overlag in subband echo cancelers is overcome by employing an X-analysis filter bank in which the pass-band of the subband filters is wider than the pass-band of the corresponding subband filters in the Y-analysis filter bank. This insures that there is sufficient energy in the tap delay lines of the adaptive filters in the subband echo cancelers at all frequencies where echos are to be synthesized. More specifically, the keeping of sufficient energy in the tap delay lines of the adaptive filters in the subband echo cancelers avoids exciting eigenmodes associated with the small eigenvalues of the correlation matrix.