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:
Jul. 16, 2002
Filed:
May. 18, 2000
James D. McVey, Palo Alto, CA (US);
Alcatel Canada Inc., Kanata, CA;
Abstract
A modulation system having in-phase and quadrature phase (IQ) calibration while on-line. The modulation system includes digital filters for converting I and Q data bit streams into filtered multilevel I and Q digital data streams, digital-to-analog converters, and an IQ modulator for converting the analog I and Q data streams into a modulated output signal having a representative IQ diagram having modulation states and transition locations between the modulation states. The system also includes an on-line correction data state detector, an IQ correction code, and a scalar amplitude detector. The on-line correction state detector monitors the data states in memories of the digital filters and detects the presence of particular data states that are expected to result in particular modulation states or transition locations. The amplitude detector monitors the modulated output signal and provides representative detected magnitudes. When one of the particular data states is detected the IQ correction code is triggered to compare the detected magnitude with magnitudes for others of the particular data states that have been detected and stored previously. The IQ correction code then uses the comparison to generate adjustments for I and Q offsets, I/Q phase, and I/Q gain. In a rotation embodiment, the modulation system further includes a rotation signal generator for generating rotation angles and an IQ rotator for applying the rotation angles for rotating the I and Q digital data streams. The rotation frequency may be used for tuning the frequency of the modulated output signal.