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:
Feb. 01, 1977
Filed:
Sep. 26, 1975
Daniel B Talbot, Cornwell Heights, PA (US);
Jerrold Electronics Corporation, Horsham, PA (US);
Abstract
Homodyne automatic frequency control circuitry maintains the mean or center output frequency of a controlled oscillator, e.g., the output of a voltage controlled oscillator effecting frequency modulation, equal to the output frequency of a reference oscillator. The composite AFC circuitry employs ganged sampling switches and a common mode error obviating common frequency detector (e.g., a discriminator) to alternately store voltages representative of the reference and controlled oscillator frequencies in capacitors connected to the inputs of a difference amplifier. The difference amplifier acts through an integrator to supply any necessary correction potential to the control port of the controlled oscillator when the signals stored in the two capacitors differ, signalling that the mean output frequency of the controlled oscillator has departed from that of the reference oscillator.