Patent ID: 6914489

Claim:
A circuit comprising: a frequency synthesizing circuit comprising a voltage controlled circuit ( 40 ) for generating an oscillating signal from an input voltage, and the frequency synthesizing circuit being configured to operate in a phase locked loop mode under control of an error signal representative of a phase differential between the oscillating signal and a reference signal; a digital processing unit ( 60 ) configured determine a first and a second frequency of the oscillating signal obtained in response to respective first and second input voltage values and, further configured to generate a control value from the two frequencies and the reference signal; a digital to analog converter ( 70 ) configured to preset the input voltage to a preset value in response to the control value; and a loop filter whose output is connected to an input of the voltage controlled circuit, and wherein the output of the digital to analog converter is directly connected to an input of the loop filter and the digital to analog converter sets the input of the loop filter to the preset value.