Patent ID: 7120396
Filing Date: 2006-10-10
Classification: H03C,H03L,H04L

Abstract:
1. A transmitter circuit means comprising: a phase lock loop including a phase detector means, a summation means, and a voltage controlled oscillator arranged in series, and a controllable frequency divider arranged to feedback an output of the voltage controlled oscillator to an input of the phase detector; and a baseband modulation source arranged to generate a modulation signal corresponding to information to be transmitted; a modulation correlation circuit means arranged to receive said modulation signal and to correlate said signal with residual modulation in the phase lock loop to generate one or more modulation correction signals; a delta-sigma modulator means arranged to receive said modulation signal and generate a delta-sigma control signal therefrom; and a modulation amplitude scaling means arranged to receive the modulation signal and the modulation correction signals and to scale the amplitude of the modulation signal in response thereto; wherein the scaled modulation signal is applied to the phase lock loop at the summation means in order to modulate the voltage controlled oscillator to produce a modulated RF output signal; and the delta-sigma control signal is applied to the controllable frequency divider in order to control the divide ratio thereof whereby the controllable frequency divider acts to substantially remove the modulation from the modulated RF output signal at the input to the phase detector.