Phase locked loop
AssigneeCambridge Silicon Radio Limited
InventorsPasquale Lamanna, Davide Orifiamma
Life of this patent
Estimating the term…
Abstract
A phase locked loop that includes a signal generator arranged to output a feedback signal, a first phase detector arranged to detect a phase difference between the feedback signal and a reference signal and to output a first phase detect signal in dependence on that detection, a second phase detector arranged to detect a phase difference between the feedback signal and a delayed version of the reference signal or between the reference signal and a delayed version of the feedback signal and to output a second phase detect signal in dependence on that detection, and an adjustor. The adjustor is arranged to determine which of the first and second phase detect signals commutes first and to alter the frequency of the feedback signal in dependence on the result of the determination.
Claims23
A phase locked loop, comprising:
- a signal generator arranged to output a feedback signal;
- a first phase detector arranged to detect a phase difference between the feedback signal and a reference signal and to output a first phase detect signal in dependence on that detection;
- a second phase detector arranged to detect a phase difference between the feedback signal and a delayed version of the reference signal or between the reference signal and a delayed version of the feedback signal and to output a second phase detect signal in dependence on that detection;
- and
- an adjustor arranged to determine which of the first and second phase detect signals commutes first and to alter the frequency of the feedback signal in dependence on the result of the determination.
A method for altering the frequency of a feedback signal comprising the steps of:
- detecting a phase difference between the feedback signal and a reference signal and outputting a first phase detect signal in dependence on that detection;
- detecting a phase difference between the feedback signal and a delayed version of the reference signal or between the reference signal and a delayed version of the feedback signal and outputting a second phase detect signal in dependence on that detection;
- determining which of the first and second phase detect signals commutes first;
- and
- altering the frequency of the feedback signal in dependence on the result of the determining step.
Dependencies are inferred from the claim text.