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. 12, 2010
Filed:
Jul. 12, 2006
Applicant:
Kazuhisa Ishiguro, Gunma, JP;
Inventor:
Kazuhisa Ishiguro, Gunma, JP;
Assignee:
Ricoh Co., Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04B 3/04 (2006.01);
U.S. Cl.
CPC ...
Abstract
A second operational amplifier () is arranged, as an interface circuit (), between a first operational amplifier () outputting the control voltage (Vcd) of a dummy filter () and a main filter (), and the reference voltage (Vr) of the second operational amplifier () is optimized such that the control voltage (Vcd) obtained by using the dummy filter () is converted through the interface circuit () into a control voltage (Vcm) most suitable for the main filter (), thereby obtaining a control voltage (Vcm) most suitable for regulating the frequency characteristics of the main filter () to desired characteristics.