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:
Apr. 24, 1990
Filed:
Jul. 31, 1989
Masahiro Takeda, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A recursive digital filter comprises an input terminal receiving an input signal, an output terminal for outputting a filtered signal, an offset value circuit for outputting a predetermined offset value, an adder having a first input connected to the input terminal and a second input connected to receive the predetermined offset value from the offset value circuit, and a recursive digital filter loop having an input connected to an output of the adder and an output connected to the output terminal. With this arrangement, the recursive digital filter loop receives the input signal added wtih the predetermined offset value, so that, even if the input signal is zero the recursive digital filter loop will process some signal which is not zero, and accordingly, the result of the processing of the recursive digital filter loop never becomes zero. Accordingly, the limit cycle caused due to accumulation of rounding error will not occur.