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. 11, 1995
Filed:
Aug. 04, 1993
Isoshi Takeda, Ukyo, JP;
Shigeyoshi Hayashi, Ukyo, JP;
Rohm Co., Ltd., Kyoto, JP;
Abstract
A stereo signal demodulator circuit demodulates a stereo signal by using a PLL circuit including a voltage-controlled oscillator (VCO) for generating a first oscillation signal and a second oscillation signal having a phase different from that of the first oscillation signal by 90.degree.. The voltage-controlled oscillator circuit includes a first amplifier for outputting a signal whose phase is different from that of an input signal by 90.degree., a second amplifier for outputting a signal whose phase is different from that of an input signal by 90.degree., and a third amplifier for outputting a signal whose phase is different from that of an input signal by 180.degree.. The first, second and third amplifiers are connected in series so that an output signal of the third amplifier is different, in phase, from the input signal of the first amplifier by 360.degree., and a positive feedback loop for feeding back the output signal of the third amplifier to the input of the first amplifier and operating currents of the first and second amplifiers are controlled by the control voltage such that the first oscillation signal is derived from the output of one of the first amplifier and second amplifiers, and the second oscillation signal is derived from one of the input and output of one of the first and second amplifiers.