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:
Jul. 08, 2008
Filed:
Apr. 04, 2003
Mathew F. Easley, Woodstock, GA (US);
Roger Darr, Sugar Hill, GA (US);
Matthew Barnhill, Duluth, GA (US);
Mathew F. Easley, Woodstock, GA (US);
Roger Darr, Sugar Hill, GA (US);
Matthew Barnhill, Duluth, GA (US);
Other;
Abstract
An algorithm calculates spectral compression/expansion filter coefficients using a value proportional to a reciprocal of a feedback/feedforward signal and stores the coefficients to a lookup table. The lookup table is indexed by a pre-selected set of coefficient bits to generate a filter coefficient function. A first portion of the lookup table stores a plurality of discrete values at index points of a line segment corresponding to a filter coefficient function approximation, so as to generate an initial discrete value corresponding to the filter coefficient function at a value of the high order bits and a second portion stores a plurality of slope values, which indicates a slope of the filter coefficient function. A linear circuit interpolates/decimates an approximation of the compression/expansion filter coefficient function based on the slope value, the initial discrete value and a preselected set of low order bits of the reciprocal value.