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:
Sep. 15, 1981
Filed:
May. 16, 1980
Donald L Fraser, Jr, Warren Township, Somerset County, NJ (US);
Armando J Vera, Methuen, MA (US);
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
Abstract
A switched capacitor filter circuit which closely matches single pole RC filters at voice frequency. The filter pole is determined by the ratio of a first and second capacitor (C.sub.1 and C.sub.2). Any resulting loss is compensated for by an operational amplifier (13) in combination with third and fourth capacitors (C.sub.3 and C.sub.4) operating as a voltage divider circuit. A switch (16) may be provided for discharging one of the latter capacitors during nonsampling intervals. A further switch (17) may also be provided to cancel charge due to gate-to-drain overlap of the first switch.