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. 11, 1976
Filed:
Nov. 20, 1974
Martin V Seitz, Fox River Grove, IL (US);
Harry A Hennen, Bloomingdale, IL (US);
Motorola, Inc., Chicago, IL (US);
Abstract
Apparatus and method for determining when a phase lock loop is in a state of lock is disclosed. The input frequency and the VCO frequency of a phase locked loop are combined by a difference multiplier to produce a signal having their difference frequency. The difference frequency signal is transformed into a squarewave by a limiter and the squarewave is then fed into a binary counter which counts the frequency of the squarewave pulses. Circuitry including a clock, two monostables, an AND gate, and a one cycle memory flip-flop periodically monitors the count of the binary counter and produces a signal indicating a state of unlock when the count of the binary counter exceeds a predetermined limit. An inhibit signal which prevents the binary counter from continuing to count is generated when the predetermined count limit has been reached in any one monitored time period.