Patent ID: 7129791

Claim:
A circuit arrangement for generating selected frequencies, comprising: a first frequency divider having a reference frequency input adapted to have a reference frequency applied thereto, and a first divider output; a loop filter having a loop filter output, and a loop filter input set including at least one loop filter input: an oscillator having an oscillator control input connected to said loop filter output, and an oscillator output; a second frequency divider having a signal input connected to said oscillator output, and a second divider output; a phase/frequency detector having first and second detector inputs respectively connected to said first and second divider outputs, and a detector output; a charge pump having a charge pump input connected to said detector output and a charge pump output connected to at least one loop filter input selected from said loop filter input set; and a regulating signal generator that has at least one input connected respectively to at least one of said first and second frequency dividers, and a regulating signal output connected at least intermittently to said charge pump and/or at least one loop filter input selected from said loop filter input set; wherein at least one of said first and second frequency dividers is a respective controllable first or second frequency divider that is adapted to divide a frequency of an input signal received at said respective input thereof by a respective controllable variable divider ratio to produce at said divider output thereof a resulting divider output signal having a divided frequency; and wherein, via said at least one input of said regulating signal generator, said regulating signal generator is adapted to receive information regarding said controllable variable divider ratio, and said regulating signal generator is adapted to produce at said regulating signal output a regulating signal responsive to and dependent on said information regarding said controllable variable divider ratio, and said regulating signal generator is adapted to vary said regulating signal in response to a change of said controllable variable divider ratio so that an output voltage produced at said loop filter output and provided to said oscillator control input is varied in a controlled manner.