APPARATUS AND METHOD FOR PHASE NOISE AND POST TUNING DRIFT CANCELLATION

摘要

APPARATUS AND METHOD FOR PHASE NOISE AND POST TUNING DRIFT CANCELLATION The tuner section of a communications receiver 10 includes a gallium arsenide voltage controlled oscillator 48 for upconverting the received signal in mixer 18. Phase noise and post tuning drift associated with oscillator 48 is impressed onto the signal supplied by a second oscillator network 46. Thus, the outputs of mixers 18 and 78 both contain noise and post tuning drift associated with the gallium arsenide oscillator 48. Mixer 28 is used to subtract the noise and drift component on line 30 from that on line 32 to thereby provide an output 14 which is substantially free of the noise and drift associated with the efficient, but noisy gallium arsenide VCO 48.