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:
Dec. 29, 1987
Filed:
Jun. 26, 1986
Arthur H van Roermund, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
A switched-capacitor multiplier circuit for multiplying an information signal x(t) by a bipolar carrier signal d(t) consisting of a distributed multiplier circuit with which the bipolar carrier signal is normally associated. To reduce offset voltages in the output signal caused by the operational amplifiers used and caused as a result of clock feed-through, it is not the bipolar carrier signal itself, but a full-wave rectified version thereof that is associated with the distributed multiplier circuit. The output signal of the multiplier circuit is applied to an auxiliary multiplier circuit multiplying it by +1 or -1 dependent on the instantaneous polarity of the bipolar carrier signal d(t). The offset voltage is thereby transposed to a frequency which is at least equal to the fundamental frequency of the carrier signal so that, if desired, it can be suppressed with the aid of a suitably chosen low-pass filter without the desired signal being affected thereby.