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. 04, 1984
Filed:
Aug. 30, 1982
Patrick D Griffis, Indianapolis, IN (US);
RCA Corporation, New York, NY (US);
Abstract
A frequency translation phase-locked loop (PLL) is provided for detecting the audio information from a television signal. The PLL includes a mixer and a phase detector, responsive to the intermediate picture and sound carriers respectively, which carriers are amplified by a single IF amplifier. A first filter is coupled between the output of the television receiver tuner and the input of the IF amplifier and has a frequency response for passing the picture and sound carriers. The input of the mixer is coupled to the output of the IF amplifier and is substantially responsive to the amplified picture carrier. The phase detector has a first input also coupled to the output of the IF amplifier and is substantially responsive to the amplified sound carrier and a second input coupled to the output of the mixer. A second filter coupled to one of the first and second inputs of the phase detector has an amplitude versus frequency response which provides a predetermined attenuation at the frequency of the picture carrier and substantially less attenuation at the frequency of the sound carrier. A lowpass filter coupled to the output of the phase detector provides the detected audio information.