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, 1998
Filed:
Feb. 26, 1997
Jun Ueshima, Tokyo, JP;
Katsunori Sato, Kanagawa, JP;
Yoshiyuki Takayanagi, Kanagawa, JP;
Hideki Hirose, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
An active filter apparatus makes it possible for a filter adjusting circuit to require a small number of elements when the filter adjusting circuit is contained in an integrated circuit, to be not easily affected by variations in the characteristics of the elements which form the circuit, and to be capable of easily adjusting the frequency characteristics of the filter to be adjusted. A characteristics conversion device converts, on the basis of an input signal and an output signal of the filter, to a characteristics conversion signal whose amplitude when the adjustment is completed is considerably larger than that of the output signal. As a result, the amplification factor of the characteristics conversion device, necessary to detect a maximum or minimum value of a characteristics conversion signal, is considerably small. Therefore, it is possible to considerably decrease an offset error of the characteristics conversion device.