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:
May. 10, 1977
Filed:
Jul. 08, 1976
Peter H Alfke, Los Altos Hills, CA (US);
Charles H Alford, Santa Clara, CA (US);
Eric G Breeze, Los Altos, CA (US);
Fairchild Camera and Instrument Corporation, Mountain View, CA (US);
Abstract
A phase-locked loop frequency synthesizer is described not having the uncontrolled modulation of its output normally associated with such a synthesizer due to a detection dead band inherent in the phase/frequency comparator which is a principal part thereof. The frequency synthesizer includes, as is conventional, a reference oscillator and an oscillator for generating the synthesizer output. The comparator is also included as is conventional to detect unwanted deviations of the phase and frequency of the synthesizer output so they can be corrected. In order to compensate for the inability of the comparator to detect small unwanted deviations, a pulse generator is added to the synthesizer to apply what is, in effect, an intentional periodic phase error signal greater than the dead band difference. This causes the phase of the desired output to be corrected in a controlled manner which will prevent undesired frequency modulation of its output.