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:
Oct. 06, 1998
Filed:
Feb. 06, 1997
Shigeru Otsuka, Tokyo, JP;
Kanada Nakayasu, Saitama, JP;
NEC Corporation, Tokyo, JP;
Abstract
A voltage-controlled oscillator generates an oscillation signal having a frequency corresponding to a control signal. A phase comparator detects a phase difference between a reference signal and a frequency-divided signal derived from the oscillation signal and generates a phase difference signal. A control circuit, which comprises an A/D converter, a high-speed processor, and a D/A converter, generates a control voltage so as to reduce a time-dependent change in the phase difference signal to synchronize the oscillation signal with the reference signal. When the synchronization of the oscillation signal with the reference signal is completed, the control circuit secures a control voltage at the time time-dependent change in the phase difference signal becomes equal to or smaller than a phase difference stored in a flash ROM.