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:
Dec. 21, 1976
Filed:
Apr. 07, 1975
William Peil, North Syracuse, NY (US);
Robert J McFadyen, Syracuse, NY (US);
General Electric Company, Syracuse, NY (US);
Abstract
A detector for AM or FM signals is described. The detector employs a differentially connected emitter follower pair to which an in-phase and a phase-shifted signal are respectively applied. The emitter follower pair produces an output waveform with controllably spaced zero crossings which is the 'greater of' the applied waveforms. For FM operation, the phase shift is made linearly frequency dependent, being in quadrature at resonance. In FM operation, the zero crossings are sensed to produce a succession of variable width unidirectional pulses whose widths are proportional to the frequency deviation. Amplitude variations in the variable width pulses may then be removed and integration in a filter with an audio frequency time constant recovers the FM modulation information. For AM operation, a phase shift of 180.degree. is used, producing full wave rectification. The AM information is then recovered from the rectified signal using the same integrating filter used for FM. The invention has preferred application to integrated circuit fabrication.