QUADRATURE MODULATION CIRCUITS AND SYSTEMS SUPPORTING MULTIPLE MODULATION MODES AT GIGABIT DATA RATES

摘要

Quadrature modulation systems, circuits and methods are provided to support various modulation modes including ASK (amplitude shift key), FSK (frequency shift key) and PSK (phase shift key) modulation at high data rates (e.g., gigabit data rates). For example, a modulation circuit includes a mixer circuit including an integrated sign modulation control circuit and a plurality of mixer ports. The mixer ports include a first input port, a second input port, an output port and a sign modulation control port. The modulation circuit generates a modulated signal by operation of the mixer circuit multiplying a modulating signal applied to the first input port with a carrier signal applied to the second input port to generate a mixed signal output from the output port, and by operation of the integrated sign modulation control circuit controlling polarity switching of a signal at one of the mixer ports in response to a sign modulation control signal input to the sign modulation control port. The sign modulation control signal can be a digital data signal having binary data encoded into the modulated signal.