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. 09, 2008
Filed:
Nov. 13, 2006
Christopher G. Regier, Austin, TX (US);
Christopher G. Regier, Austin, TX (US);
National Instruments Corporation, Austin, TX (US);
Abstract
A front-end circuit suitable for digital multimeters and measurement devices may be configured with strictly capacitive attenuators replacing the resistive attenuators in the AC signal path. An inverting programmable-gain amplifier (PGA) may be built around an operational amplifier (op-amp), with a single resistor for DC feedback providing a 1-order response for AC coupling. The single resistor may be replaced by a more complex RC network to provide a 2-order response. The feedback circuit may also include active components such as additional op-amps, which may assist in shaping the overall response and/or reducing the DC offset at the output of the circuit. The capacitive load presented to the input by the front-end circuit may be minimized to compare to capacitances present in resistive implementations. The circuit would not present a DC load to the input since DC loads are typically the result of a resistive attenuator in the DC signal path.