Tektronix TVS600 & TVS600A Series Computer Accessories User Manual


 
Appendix C: Algorithms
C–12
TVS600 & TVS600A Command Reference
Amplitude (voltage) measurement. Overshoot finds the first positive-going edge
in the waveform record (or gated area) and calculates value as follows:
Overshoot =
Max * High
Amplitude
100%
This measurement ignores settings of the CALCulate:WMParameter:EDGE and
:SLOPE commands when locating the edge to measure.
Timing measurement. The time relative to the trigger point at which the
positive-going crossing that you specify occurs. The PCROSs measurement
searches for the N
th
occurrence of an edge; during the search it counts only
positive edges.
1. Searching from Start to End of waveform record, find the first positive-go-
ing transition through MREF (middle reference).
2. Continue the search process until the N
th
positive-going crossing is found
(user specifies N).
3. PCross = Time@pcrossing, whereTime@trigger = 0.
Pretrigger crossings return negative times; posttrigger crossings return
positive times.
Positive values for N force the search at the start of the waveform record;
Negative values and zero, at the end (zero designates the last crossing, –1 the
next to the last crossing, and so on in the waveform record).
Amplitude measurement. The absolute difference between the maximum and
minimum amplitude.
PeaktoPeak = MaxMin
Timing measurement. Time taken for one complete signal cycle. The reciprocal
of frequency. Measured in seconds.
Period = MCross3MCross1
Timing measurement. The amount of phase shift, expressed in degrees of the
target waveform cycle, between the MidRef crossings of two different wave-
forms. Waveforms measured should be of the same frequency or one waveform
should be a harmonic of the other.
Phase is a dual waveform measurement; that is, it is measured from a target
waveform to a reference waveform. To get a specific phase measurement, you
must specify the target and reference sources.
Overshoot
Pcross
Peak to Peak
Period
Phase