Patent ID: 6271737
Filing Date: 2001-08-07
Classification: H03B,H03D,H03L,H04B

Abstract:
A communications device comprising frequency conversion means having a first input for a signal to be frequency converted and a second input for a converting signal generated by a frequency generating means, the frequency generating means comprising a voltage controlled oscillator (VCO) including an active element having a control electrode, a current supply electrode and an output electrode, a dc voltage source coupled between the current supply electrode and the output electrode, frequency determining reactive elements coupled to the active element for determining the frequency to be generated, at least one of the reactive elements being adjustable in response to an applied voltage and means for deriving a dc signal from the dc voltage of the dc voltage source which signal includes at least a component responsive to voltage perturbations in said dc voltage, and means for phase modulating the VCO in response to said dc signal in an opposite sense to a phase modulation caused by modulation of parameters of the active element due to said voltage perturbations.