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:
Jul. 11, 1989
Filed:
Nov. 25, 1987
James S Butcher, Phoenix, AZ (US);
Siemens Transmission Systems, Inc., Phoenix, AZ (US);
Abstract
A high resolution digital phase-lock loop circuit is described, which is implemented with an input clock reference frequency which is approximately the same as the output frequency of the phase-lock loop. The output is derived from delaying the input clock a variable number of gate delays ranging from no delay to one period of the input clock. A shift register controls the number of gate delays and a 360 degree phase detector initializes the shift register when the output is delayed by one period of the input clock to provide no delay. Gate delay variations due to integrated circuit process, voltage and temperature are compensated for to provide a relatively constant clock phase correction.