Linear all-digital phase locked loop

Details Linear all-digital phase locked loop Linear all-digital phase locked loop

1986-10-09

1987-12-08

Heyman, John S.

Electrical pulse counters, pulse dividers, or shift registers: c

Systems

Having phase shift

377 47, 328 63, 331 1A, H03L 718, H04L 702

Patent

active

047122234

ABSTRACT:
A digital phase locked loop to function as a stable reference clock given a gapped, or pulse stuffed, input clock signal which may have a frequency offset relative to the nominal specified frequency and a phase jitter relative to the average frequency of the input signal, the digital phase locked loop comprising an input synchronizer for synchronizing the input clock signal to a stable high frequency reference clock. The output of the input synchronizer increments a write counter and resets a phase counter to zero at the begininning of each cycle of the input clock signal. The outputs of the write counter and the phase counter are sampled by a sampling circuit which interprets the sampled data in two's complement form. A digital filter receives the output of the sampling circuit and performs a low pass filter function on the sampled data and calculates a linearized approximation of the frequency to be generated by the offset (non-symmetric) digitally controlled oscillator (ODCO) which receives the output of the digital filter. The ODCO uses its input to determine the frequency of discrete phase adjustments placed in its output signal. The output of the ODCO is divided by a read counter. Each time the read counter enters a predetermined state, the sampling circuit is caused to sample the input clock signal and the process is repeated again and again.

REFERENCES:
patent: 4577163 (1986-03-01), Culp
patent: 4627080 (1986-12-01), Debus, Jr.

Affiliated with

Also associated with

Rating

Linear all-digital phase locked loop does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Linear all-digital phase locked loop, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Linear all-digital phase locked loop will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-25282