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. 11, 2014
Filed:
Sep. 16, 2010
Kazuo Akaike, Sayama, JP;
Nobuo Tsukamoto, Akishima, JP;
Tsukasa Kobata, Sayama, JP;
Nihon Dempa Kogyo Co., Ltd., Tokyo, JP;
Abstract
There is provided a frequency synthesizer capable of improving phase noise. A sinusoidal signal with a frequency set by a frequency setting part is output as a digital signal from a set signal output part, and the digital signal is D/A-converted. A difference between a sinusoidal signal with a frequency corresponding to an output frequency of a voltage controlled oscillating part and a sinusoidal signal output from a D/A converting part is amplified by a differential amplifier, and an amplified signal is input via an A/D converting part to a means for extracting a phase difference between the aforesaid sinusoidal signals. A voltage corresponding to a signal being the result of integration of the phase difference is input as a control voltage to the voltage controlled oscillating part. Then, a gain of the differential amplifier is set larger than a maximum value of phase noise degradation of the A/D converting part, whereby the phase noise degradation of the A/D converting part is cancelled.