[Ether]

Given a 128 CPR encoder running at approx 3280 rpm (per post#1), there will be approx 70 counts every 10 ms.

If a 10ms timed loop is used and the rate is computed by reading the raw sample count and dividing by sample time, a 1-count jitter will equal approx 1/70 of 3280, or 47rpm jitter.

Using this processing method and decoding at 4x instead of 1x should reduce the jitter, although perhaps not by a factor of 4 (because of the tolerances of the edge locations).