Appendix B: Algorithms
TDS 684A, TDS 744A, & TDS 784A User Manual B–11
2. From this sample, continue the search to find the first (positive) crossing of
. The time of this crossing is the low rise time or . (Use linear
interpolation if necessary.)
3. From , continue the search, looking for a crossing of . Update
 if subsequent  crossings are found. If a  crossing is
found, it becomes the high rise time or . (Use linear interpolation if
necessary.)
4.  =  – 
High
HighRef
LowRef
Low
THRTLR
Rise Time
Figure B–3: Rise Time
Amplitude (voltage) measurement. The true Root Mean Square voltage.
If  =  then  = the (interpolated) value at .
Otherwise,
 = ŕ

Ă(())2dt
( *) 
Ǹ
For details of the integration algorithm, see below.

RMS: