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:
May. 21, 2013
Filed:
Mar. 06, 2009
Mark Whittington, Austin, TX (US);
Zaher G. Harb, Round Rock, TX (US);
Mark Whittington, Austin, TX (US);
Zaher G. Harb, Round Rock, TX (US);
National Instruments Corporation, Austin, TX (US);
Abstract
Various embodiments of a self-calibration circuit may solve the problem that arises in high performance oscilloscopes and in particular, RF oscilloscopes, of internally providing a precision calibration signal without degrading the bandwidth, flatness of the frequency response, and input return loss of the oscilloscope. The self-calibration circuit may be configured to implement an impedance transformation technique where active and passive circuit elements with carefully chosen values are configured in an impedance converter. During self-calibration, switching elements comprised in the self-calibration circuit may be toggled to create a servo loop comprising an amplifier within the circuit, with an attenuator and resistive component acting as feedback elements. The circuit may hence become an impedance gyrator and behave as a precision source with an impedance matching the input impedance of the load circuit.