Appendix B: Algorithms
B–10
TDS 684A, TDS 744A, & TDS 784A User Manual
Phase =
MCross1Ref * MCross1Target
Period
360
If the target waveform leads the reference waveform, phase is positive; if it lags,
negative.
Phase is not available in the Snapshot display.
Timing measurement. The ratio of the positive pulse width to the signal period,
expressed as a percentage.
PositiveWidth is defined in Positive Width, following.
If Period = 0 or undefined then return an error.
PositiveDutyCycle =
PositiveWidth
Period
100%
Amplitude (voltage) measurement.
PositiveOvershoot =
Max * High
Amplitude
100%
Note that this value should never be negative.
Timing measurement. The distance (time) between MidRef (default = 50%)
amplitude points of a positive pulse.
If MCross1Polarity = ‘+’
then
PositiveWidth = (MCross2 – MCross1)
else
PositiveWidth = (MCross3 – MCross2)
Timing measurement. Time taken for the leading edge of a pulse to rise from a
LowRef value (default = 10%) to a HighRef value (default = 90%).
Figure B–3 shows a rising edge with the two crossings necessary to calculate a
Rise Time measurement.
1. Searching from Start to End, find the first sample in the measurement zone
less than LowRef.
Positive Duty Cycle
Positive Overshoot
Positive Width
Rise Time
