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:
Nov. 06, 1984
Filed:
May. 17, 1982
Johan M Schmidt, Eindhoven, NL;
U.S. Philips Corp., New York, NY (US);
Abstract
FM-broadcasting system comprising a FM-transmitter (1-16, 32-34) and a receiver (14-31, 35, 36) cooperating therewith, the transmission signal of which comprises a multiplex signal which is frequency-modulated on a main carrier wave, which multiplex signal comprises an audio-frequency information signal (L+R) and, in the case of a stereo transmission, a stereo information signal (L-R) modulated on a (38 kC) suppressed stereo subcarrier wave, also comprising a (19 kC) stereo pilot which is situated between the frequency spectra of the two information signals and a binary, differentially coded code signal which is phase-modulated on a (16.625 kC) code subcarrier wave which is situated outside the frequency spectra, and does not coincide with the (19 kC) stereo pilot, the receiver (14-31, 35, 36) comprising a pilot regeneration circuit (22-25) for regenerating the (19 kC) stereo pilot, the code signal having a bit repetition period which is an integral number of times the period of the (19 kC) stereo pilot. The signal delay (.tau.) required for differentially decoding the code signal is stabilized by a clock signal derived from the (19 kC) stereo pilot, use then being made of the fixed frequency relationship between the bit frequency of the code signal and the stereo pilot frequency, so that disturbances due to variations in the signal delay are avoided.