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:
Feb. 12, 2008
Filed:
Jul. 18, 2006
Applicant:
Koji Nakamuta, Kawasaki, JP;
Inventor:
Koji Nakamuta, Kawasaki, JP;
Assignee:
Fujitsu Limited, Kawasaki, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03L 7/06 (2006.01);
U.S. Cl.
CPC ...
Abstract
The invention relates to a digital synchronization network, and provides a DPLL circuit having a holdover function that generates a high-precision reference clock with a temperature correction to perform a free-running frequency control at a holdover time. In a holdover mode of the DPLL circuit using a DDS, the DPLL circuit having a holdover function adds a correction value calculated from a temperature characteristic of a slave oscillator to a fixed DDS control value during a detection of a holdover, thereby changing the DDS control value according to the temperature characteristic.