PHASE-LOCKED LOOP UPDATE CANCELLATION

Organization Name

International Business Machines Corporation

Inventor(s)

John Borkenhagen of ROCHESTER MN US

Christopher Steffen of ROCHESTER MN US

Grant P. Kesselring of ROCHESTER MN US

James Strom of ROCHESTER MN US

PHASE-LOCKED LOOP UPDATE CANCELLATION

This abstract first appeared for US patent application 18492453 titled 'PHASE-LOCKED LOOP UPDATE CANCELLATION

Original Abstract Submitted

A pulse limiter circuit of a phase-locked loop (PLL) receives, from a phase frequency detector of the PLL, first second input pulses, where pulse widths of the first and second input pulses indicate whether a reference clock signal leads or lags a feedback clock signal. The pulse limiter circuit determines whether a pulse width of the first or second input pulse is greater than a selected duration indicative of transient phase jitter. Based on determining the pulse width of the first or second input pulse is greater than the selected duration, the pulse limiter circuit sets a pulse width of a first output pulse equal to a pulse width of a second output pulse width and outputs the first and second output pulses to a charge pump of the PLL, such that no phase adjustment to the feedback clock signal is made based on the first and second input pulses.