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. 15, 1987
Filed:
Dec. 10, 1984
Fred T Cheng, Cupertino, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An AM stereo receiver uses an AM detector (208) and an asynchronous PM detector (206) to decode AM stereo signals. The AM stereo broadcast signal has a carrier signal phase modulated with a modified phase shifted left channel minus right channel (L-R) audio signal, which is then amplitude modulated with a phase shifted left channel plus right channel (L+R) audio signal. The AM detector (208) within the receiver decodes the phase shifted L+R signal, while the PM detector 206 within the receiver decodes the modified phase shifted L-R signal. A phase shifter (214) restores the L+R and L-R signals to their proper phase relationship. A matrix circuit (228) regenerates the left and right channel signals from the L+R and L-R signals.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile