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:
Jul. 08, 2008
Filed:
Jan. 26, 2005
Yuji Hattori, Tokyo, JP;
Yuji Hattori, Tokyo, JP;
Seiko NPC Corporation, Tokyo, JP;
Abstract
The present invention provides a spread spectrum type clock generation circuit whose EMI for peripheral equipment is reduced. The clock generation circuit comprises a phase-locked loop circuit and a clock modulation circuit. The clock modulation circuit comprises a ΔΣ modulator, to frequency-modulate an output clock by modulating the frequency division number of a frequency divider in the phase-locked loop circuit by a digital circuit, and further comprises a modulation pattern controller for distributing the peak of a triangular waveform which is a modulation waveform generated by a modulation pattern generator to change the amplitude and the period thereof, thereby making it possible to eliminate dullness and distortion of a modulation waveform in a modulating method using a conventional analog circuit and to obtain an output clock having higher modulation efficiency than that in a case where a normal triangular waveform is employed in a conventional modulating method using a digital circuit.