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:
Jan. 26, 1999
Filed:
Mar. 27, 1997
Timothy J Everett, Horley, GB;
U.S. Philips Corporation, New York, NY (US);
Abstract
Techniques for applying attenuation to audio signal frames in MPEG and similar compression systems are described, together with a method for mixing such signals without decompression. Each entry in a data frame (F) has an associated scale-factor index (SF), identifying a respective entry in a sequentially arranged and spaced table of scale-factor values. The attenuation technique (20), which suitably precedes mixing for at least one channel involves simple addition to scale factor index values to refer to a different scale-factor value. Respective sub-band data groups from each channel are compared in terms of their respective scale factors and following scaling the data for the two groups is added together. The scale-factor table spacing, which suitable corresponds to a 1 dB attenuation, is used for quick scaling of the results of the addition if overflow is determined to have occurred.