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:
Sep. 12, 1989
Filed:
Sep. 28, 1987
Akira Usui, Hamamatsu, JP;
Yamaha Corporation, Hamamatsu, JP;
Abstract
A digital filter of an FIR (non-recursive) type operating as an oversampling filter in digital signal processing such as for a stereophonic audio device comprises a memory storing impulse response coefficient data, a mantissa data producing circuit for converting the coefficient data to mantissa data, a multiplier for multiplying input data with the mantissa data, an accumulator for accumulating output data of the multiplier, and a bit-shifting circuit for bit-shifting accumulated output data of the accumulator by the number of bits substantially corresponding to the change in the number of bits of exponent data in the coefficient data. The mantissa data is combined with input data in the convolution operation and the exponent data is imparted, in accumulation of multiplied values, by the bit-shifting of the accumulation output data. In one aspect of the invention, the bit-shifting is performed in a decreasing direction starting from the coefficient of the smallest exponent.