Patent ID: 7817768

Claim:
A phase locked loop frequency generator for generating an output signal with a settable target frequency, the phase locked loop frequency generator comprising: a voltage-controlled oscillator for generating the output signal; a switchable frequency divider connected to the voltage-controlled oscillator for deriving a frequency-divided signal whose instantaneous frequency is based on a value of an adjustable divisor from the output signal; a switchable delay unit connected to the frequency divider for generating a delayed signal by delaying the frequency-divided signal by delay times that are based on a control word; and a controller connected to the switchable delay unit for determining the control words, the controller having a sigma-delta modulator and determines the control words based on at least one signal provided by the sigma-delta modulator, said controller including an input for receiving a parameter determining said target frequency for said output signal, wherein the sigma-delta modulator includes an accumulator, which accumulates an input signal of the sigma-delta modulator and provides an accumulated signal, and wherein the controller determines the control words based on the accumulated signal.