Tektronix TDS 644A Sprinkler User Manual


 
Appendix B: Algorithms
Appendices
AĆ16
If the target waveform leads the reference waveform, phase is positive; if it
lags, negative.
Phase is not available in the Snapshot display.
Positive Duty Cycle
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%
Positive Overshoot
Amplitude (voltage) measurement.
PositiveOvershoot =
Max * High
Amplitude
100%
Note that this value should never be negative.
Positive Width
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)
Rise Time
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 AĆ3 shows a rising edge with the two crossings necessary to calcuĆ
late a Rise Time measurement.
1. Searching from Start to End, find the first sample in the measurement
zone less than LowRef.
2. From this sample, continue the search to find the first (positive) crossing
of LowRef. The time of this crossing is the low rise time or TLR. (Use
linear interpolation if necessary.)