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:
Aug. 18, 1992
Filed:
May. 25, 1990
Applicant:
Inventors:
Raymond A Birgenheier, Spokane, WA (US);
David M Hoover, Newman Lake, WA (US);
Assignee:
Hewlett-Packard Company, Palo Alto, CA (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04L / ;
U.S. Cl.
CPC ...
375 67 ; 332103 ; 36472404 ;
Abstract
In a conventional ROM-based digital filtering methodology, N past samples of M-bit input symbols are used to address a memory containing a desired filtered output signal. This memory must have an address space of 2.sup.M*N. According to the present invention, a desired filtered output signal is defined as a composition of signal terms, each of which is a function of less than M*N bits. Individual ROMs are provided for each of these component terms. Address bits for the ROMs are derived from the N past samples of the M-bit input symbols. The ROM outputs are combined to yield the desired filtered output signal.