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:
Feb. 17, 1987
Filed:
Oct. 27, 1982
William G Crouse, Raleigh, NC (US);
David R Irvin, Raleigh, NC (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
The subject suppressor is an improved form of echo suppressor used in conjunction with adaptive sub-band speech coders. The suppressor analyzes and uses N contiguous sub-bands of a sub-band speech coder. The intermediate results calculated during the normal operation of such speech coders may be analyzed in the suppressor to determine predictions for the echo levels of each sub-band and to set break in and break out thresholds. A substantial performance improvement with little increase in complexity over current echo suppressors is achieved. The subject suppressor may also be used with adaptive transform speech coders in which the corner frequency points define the edges of 'sub-bands' for purposes of this invention. Sub-bands are defined here as contiguous segments of the frequency-energy spectrum. The sub-bands so defined can be formed or analytically divided by a bank of filters as in normal sub-band coders or they can be identified or analyzed as noted above by the corner points of an adaptive transform coder.