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:
Aug. 16, 2005
Filed:
Apr. 18, 2003
Linley F. Gumm, Beaverton, OR (US);
Linley F. Gumm, Beaverton, OR (US);
Tektronix, Inc, Beaverton, OR (US);
Abstract
An improved self-adjusting I-Q modulator system has a quadrature modulated carrier output that is input to a waveform acquisition circuit for obtaining a full waveform from which both amplitude and phase measurements are obtained. Calibration occurs by setting respective I and Q inputs to the multipliers to zero and adjusting corresponding variable offset voltages to null the modulated carrier output. Then a voltage reference is selected by each I and Q input path in turn, and the amplitude and phase of the modulated carrier output for each I and Q channel are measured. Respective phase shifters for a carrier signal are adjusted to move the outputs of the phase shifters toward a quadrature relationship in response to the measured amplitude and phase of the full waveform. These steps are repeated until the phases of the I and Q channels are in quadrature.