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. 04, 1995
Filed:
Aug. 05, 1993
Applicant:
Inventors:
Kevin T Collier, Gardena, CA (US);
Kevin T Chan, Pasadena, CA (US);
Assignee:
Hughes Aircraft Company, Los Angeles, CA (US);
Primary Examiner:
Int. Cl.
CPC ...
H04H / ;
U.S. Cl.
CPC ...
381-7 ; 375259 ; 375340 ; 331 20 ; 331 25 ;
Abstract
A digital FM stereo decoder uses the phase characteristics of linear phase FIR filters, together with a trignometric operation, to generate a 38 kHz subcarrier signal from a 19 kHz pilot. The subcarrier signal is mixed with the input composite signal from which the pilot has been removed to shift its L-R component to baseband; the linear phase FIR filters also maintain phase coherence between the subcarrier and the composite signals. A low distortion output is obtained without the use of a phase locked loop for the regeneration of the subcarrier signal.