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.

Date of Patent:
Dec. 09, 2003

Filed:

Apr. 16, 2002
Applicant:
Inventors:

Hisae Terashima, Tokyo, JP;

Hiroyuki Ueda, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03L 7/00 ;
U.S. Cl.
CPC ...
H03L 7/00 ;
Abstract

A phase error signal indicating a most recent phase difference between an input clock signal and a feed-back signal is produced in a phase comparing unit. Also, the phase difference of the phase error signal is monitored in an abnormal condition detecting unit. When the phase difference is higher than a threshold value, the abnormal condition detecting unit judges that the input clock signal is set in an abnormal condition, and a frequency-controlled clock signal is produced in the voltage controlled oscillator according to the phase error signal. Therefore, the oscillation clock signal can be output without changing a phase of the oscillation clock signal while suppressing wonders or jitters.


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