Patent ID: 6646478
Filing Date: 2003-11-11
Classification: H03D

Abstract:
A phase and frequency detector (PFD) operable to detect phase and frequency differences between a first input signal and a second input signal, comprising:a first and second logical component operable to capture phase differences between the first and second input signals of up to about Â±360Â°, wherein the first logical component captures phase differences in the positive direction and the second logical component captures phase differences in the negative direction; a third and fourth logical component operable to capture phase differences between the first and second input signals of between about Â±360Â° to about Â±540Â°, wherein the third logical component captures phase differences in the positive direction and the fourth logical component captures phase differences in the negative direction; a plurality of resetting control blocks operable to reset the first, second, third and fourth logical components; a first summation block to combine an output of the first logical component and an output of a third logical component to produce an up output signal that represents the positive input phase difference; and a second summation block to combine an output of the second logical component and an output of the fourth logical component to produce a down output signal that represents the negative input phase difference.