Patent ID: 6526109
Filing Date: 2003-02-25
Classification: H03L,H04L

Abstract:
An apparatus for adjusting propagation delays within a phase lock loop circuit to match the phase of a first signal to the phase of a second signal the apparatus comprising:a delay cell for receiving the first signal, said cell delaying the first signal by an amount proportional to a delay control signal being received by the delay cell, and producing a delayed first signal; a bang bang phase detector for receiving the delayed first signal and comparing the phase of the delayed first signal to the phase of the second signal and outputting at least one phase signal indicating if the phase of the second signal is leading or lagging the phase of the delayed signal; a filter for integrating the phase signal and producing an averaging signal indicating whether, on the average if the phase of the second signal is leading or lagging the phase of the delayed signal; a comparator for receiving the averaging signal and producing a binary indication of whether on the average the second signal is leading or lagging the phase of the delayed signal; an up/down counter for receiving the binary indication and counting in a first direction if the second signal is leading the phase of the delayed signal and counting in a second direction if the second signal is lagging the phase of the delayed signal; and a counter output from the up/down counter coupled to the delay cell for producing the delay control signal.