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. 18, 1986
Filed:
Aug. 16, 1982
Edward R Klinkovsky, Brenham, TX (US);
William A Severin, Houston, TX (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
A PSK integrated circuit modem employs multi-mode filters in its switched capacitor circuitry for providing a plurality of filter response to accomodate a plurality of modem protocols. Each capacitor is selectively connected or disconnected from the circuit by a transistor switch, and selectively connected and disconnected from the circuit voltage reference by a transistor switch. The switches operate out of phase with each other so that when any capacitor is connected in the circuit, it is disconnected from the reference voltage and when any capacitor is disconnected from the circuit, it is connected to the reference voltage. The modem switch minimizes the effect of stray capacitance from the unselected capacitors and their associated transistor switches that have been turned off.