Variation in the timing of a signal edge relative to a defined reference or expected event time.
Also called: timing jitter; sensor signal jitter; signal edge timing variation.
Defining the reference for timing jitter
Timing jitter is variation relative to a defined nominal event or time reference. For product detection, specify whether the comparison is between a repeatable optical event and sensor output, or between that output and a later controller record. Those observation points answer different questions.
Variation in the arrival times of different products is not automatically sensor jitter. Keep the reference event and sensing conditions sufficiently defined to distinguish variation in product arrival from variation in the response being measured.
Can average delay stay the same while timing variation changes?
Yes. The average delay can remain unchanged while individual delays spread farther apart. A jitter value therefore needs a statistic and observation set. The example below calculates peak-to-peak span; it does not assume a distribution.
Is an extra pulse the same fault as timing jitter?
No. An intended edge arriving earlier or later differs from an unintended extra transition. Name which phenomenon appears in the evidence before discussing filtering or debouncing. A timing-span result alone cannot show whether a product was missed, counted twice or correctly counted. Follow the event through the signal path and compare it with an independent product reference.