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. 20, 1999
Filed:
Jan. 22, 1997
Felix Aschwanden, Thalwil, CH;
RCA Thomson Licensing Corporation, Princeton, NJ (US);
Abstract
A filtering method and apparatus in which an input signal is subjected to an analog filtering step, then an analog to digital conversion step and finally a digital filtering step to produce a filtered output signal. The pulse response of the digital filter is the mirror image of the pulse response of the analog filter and the cascaded filtering steps result in a filtered output signal which exhibits little or no group delay or phase distortion. The digital filter may be a FIR filter. Also disclosed is a phase error correction method whereby a pulse is inserted into a circuit or data stream prior to a group delay imparting device or function, a pulse response of the group delay imparting device or function is measured prior to a phase correcting device or function, mirror image filter coefficients are calculated using a window function and then incorporated into a phase correcting filter arrangement.