Patent ID: 9001955
Filing Date: 2015-04-07
Classification: H03L,H04L

Abstract:
1. A phase-locked loop having: an oscillator for forming an oscillating output signal; a frequency divider connected to receive the output of the oscillator and frequency divide it by a value dependent on a division control signal; and a phase comparator for comparing the phase of the divided signal and a reference signal to generate a control signal, the operation of the oscillator being dependent on the control signal; a first mode of operation in which the frequency divider is configured to operate in dependence on a first division control signal such that the resultant oscillating output signal has a first frequency and first phase, a second mode of operation in which the frequency divider is configured to operate in dependence on a second division control signal such that the resultant oscillating output signal has a second frequency and second phase different from the first frequency and first phase, the first division control signal being generated independently of the oscillating output signal such that, when the phase-locked loop is operating in the second mode, the first division control signal remains operative to produce the same phase as when the phase-locked loop is operating in the first mode.