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:
Apr. 28, 2015
Filed:
May. 11, 2012
Eizo Ichihara, Tokyo, JP;
Eizo Ichihara, Tokyo, JP;
Asahi Kasei Microdevices Corporation, Tokyo, JP;
Abstract
There are provided an accumulator-type fractional N-PLL synthesizer for suppressing the fractional spurious caused by periodically switching a frequency division number of a fractional frequency divider, and a control method thereof. In an accumulator-type fractional N-PLL synthesizer (), a pulse signal proportional to a fractional phase error occurring between a reference signal and an output signal of a fractional divider () for feeding back an output of a VCO () of an output stage to a preceding stage is generated using an error signal from an accumulator (). Through the use of the pulse signal, pulse widths of a UP signal and a DN signal output from a phase detector () are controlled so as to reduce a fractional phase error occurring between the UP signal and the DN signal. Thus, the fractional spurious caused by periodically switching the frequency division number of the fractional divider () is suppressed.