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:
Jan. 21, 2003
Filed:
Jan. 18, 2002
Applicant:
Inventors:
Yuji Segawa, Kawasaki, JP;
Asao Kokubo, Kawasaki, JP;
Assignee:
Fujitsu Limited, Kawasaki, JP;
Primary Examiner:
Int. Cl.
CPC ...
H03K 5/00 ;
U.S. Cl.
CPC ...
H03K 5/00 ;
Abstract
The switched capacitor filter circuit comprises an amplifier whose feedback capacitance Cf is variable. This feedback capacitance is changed based on the control signals received from the outside. Two switches control charging/discharging of a first capacitor. Another Two switches control charging/discharging of a second capacitor. Frequency f of a signal for switching the four switches is changed so that a beat frequency varies within a range having no influence with respect to a cutoff frequency while always keeping a value of the f /Cf constant.