Tektronix TDS 500C Graphics Tablet User Manual


 
Appendix B: Algorithms
TDS 500C, TDS 600B, & TDS 700C User Manual
B–13
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 = (MCross2MCross1)
else
PositiveWidth = (MCross3MCross2)
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.
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.)
Positive Duty Cycle
Positive Overshoot
Positive Width
Rise Time