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:
Sep. 03, 1996
Filed:
Sep. 05, 1995
Raymond L Barrett, Jr, Ft. Lauderdale, FL (US);
Barry W Herold, Boca Raton, FL (US);
Grazyna A Pajunen, Delray Beach, FL (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
A method and apparatus determine an instantaneous phase difference (207) between a reference signal (103) and a controlled signal (120). The reference signal (103) is derived by frequency dividing a first signal by a counter (106) including an output (107) having K sequential states, wherein K is an integer value equal to the frequency of the first signal (103) divided by the frequency of the desired reference signal, and wherein the output (107) changes by no more than one bit between any adjacent states of the K sequential states. The output (107) of the counter (106) is recorded (206) at a time concurrent with a first predetermined event occurring in the controlled signal (120), thereby generating a recorded count value that is free from metastability induced errors. The recorded count value is decoded (208) to produce a sequential state number S.sub.E corresponding to the first predetermined event. The instantaneous phase difference (207) is then calculated (210) from S.sub.E, K, and other predetermined constants.