Patent ID: 6687311
Filing Date: 2004-02-03
Classification: H04L

Abstract:
A direct quadrature amplitude modulation (QAM) apparatus, comprising:an analog modulator for providing in-phase and quadrature-phase QAM signal components; a radio-frequency (RF) driver responsive to said analog modulator for providing a RF signal comprising said QAM signal components; means for monitoring said RF signal components to provide at least one of phase and amplitude adjustment information therefor; a digital filter coupled to receive the adjustment information; said digital filter comprising a digital complex equalizer that is responsive to the adjustment information for providing a digital equalizing signal for compensating at least one of phase and amplitude errors in the analog modulator; a digital-to-analog converter coupled to receive the digital equalizing signal to provide a corresponding analog equalizing signal; and means for providing the analog equalizing signal to the analog modulator to adjust at least one of the phase and amplitude of the in-phase and quadrature-phase signal components provided thereat.