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:
Oct. 11, 1977
Filed:
Nov. 02, 1976
Johnny Collins, Oak Park, IL (US);
Zenith Radio Corporation, Glenview, IL (US);
Abstract
A low-pass filter useful in association with a phase locked loop for controlling the frequency of a voltage controlled oscillator on the basis of an error signal resulting from a comparison between a reference signal and the oscillator's output. The low-pass filter comprises means responsive to the error signal for developing an output current for charging or discharging a capacitive network according to the frequency and phase deviations represented by the error signal. For large frequency and phase deviations extended charging or discharging currents provide high acquisition speeds whereas, as the frequency and phase deviation represented by the error signal decreases, drastically reduced charging or discharging currents result thereby effectively reducing the bandwidth of the filter for facilitating reference signal sideband supression as frequency 'lock-on' is approached and when phase lock is achieved.