<p>A phase-locked loop comprising; an oscillator configured to output an oscillating signal in dependence on the control signal at an input of the oscillator; a phase detector and loop filter configured to output a low frequency compensation signal in dependence on the output of the oscillator and a reference signal; a correlator configured to frequency correlate an interferer signal and the low frequency compensation signal, and in dependence on that correlation generate a correlation signal; and an adaptive filter configured to adapt the interferer signal in dependence on the correlation signal to output a high frequency compensation signal; and a summation unit configured to combine the low frequency compensation signal and the high frequency compensation signal to form a control signal to drive the input of the oscillator.</p>
