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:
Nov. 04, 1997
Filed:
Oct. 13, 1995
Douglas J Chapman, Lake Oswego, OR (US);
Jeffrey D Currin, Pleasanton, CA (US);
Credence Systems Corporation, Fremont, CA (US);
Abstract
A timing vernier produces a set of timing signals of similar frequency and evenly distributed in phase by passing an input reference clock signal through a succession of delay stages, each stage providing a similar signal delay. A separate one of the timing signals is produced at the output of each delay stage. The reference clock signal and timing signal output of the last delay stage are supplied as inputs to a phase lock controller through separate adjustable first and second delay circuits. The phase lock controller controls the delay of all stages so that the timing signal output of the last stage is phase locked to the reference clock. In accordance with the invention, the delays of the first and second delay circuits are adjusted to compensate for controller phase lock error.