Tektronix WFM2200A, User Manual, Page: 161 / 276

Timing displays for simple
versus complex timing
The number of circles, with each representing a time offset, varies with the
complexity of the timing between the reference and input signals.
Integer multiples of reference rates.
If you are timing input signals with rates that
are integer multiples of the reference rates, the instrument can measure the timing
deterministically and displays the relationship as one circle (offset) relative to the
cross-hair.
Such cases include timing an NTSC input (multiplier of 1) or a 525 SDI input
whose frame time is 33.36 ms (multiplier of 2), against an NTSC reference,
which has a frame time of 66.73 ms.
Non-integer multiples of reference rates. If you time input rates that are not integer
multiples of the reference rates, the instrument cannot measure the timing
deterministically, so it displays the relationships as several circles. Each circle
represents a possible timing offset measurement relative to the reference cross-
hair. Display emphasis is given to the circle that times closest to zero offset and
the numerical readouts track this pair.
Figure 48: Timing display of non-integer multiples of reference rates
Non-deterministic cases include timing of slow rate inputs against fast frame-rate
references or when timing video against film rates.
Display modes
WFM2300 and WFM2200A Waveform Monitors User Manual 139