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:
Feb. 07, 1989
Filed:
Mar. 31, 1986
Toshimichi Nishimura, Kanagawa, JP;
Atsushi Kikuchi, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
An n-th degree switched capacitor filter having transfer characteristics expressed by a transfer function H(Z) can be configured by expanding the transfer function H(Z) to an n-element linear simultaneous state equation of n state voltages inclusive of an output voltage. The coefficients of the linear state equation a.sub.11 to a.sub.n2, b.sub.11 to b.sub.nn are determined in a range within which the filter circuit can be configured by hardware and further each state voltage is below a maximum output voltage. In practice, the filter is configured by plural leapfrog type differential operational amplifiers having base capacitors C.sub.o, plural transmission gates, and plural electric charge transfer capacitors C.sub.T so as to determine each coefficient on the basis of ratios C.sub.T /C.sub.o. The filter is realized by a monolithic integrated circuit (IC) and provided with a higher signal-to-noise (S/N) ratio and a wider dynamic range without deteriorating electrical characteristics and increasing cost.