HP 54540 Series - Page 237

Figure 13-4
Measurements
Calculating Minimum and Maximum from the Data Record
Calculating Minimum and Maximum from the Data
Record
The maximum and minimum voltage levels are determined from the
histogram. If the waveform is clipped, this information is also recorded. After
the minimum and maximum measurements are complete, the Vmin, Vmax,
Vp-p, Tmin, Tmax, and Tvolt measurements can be made. The remaining
primitives of the measurement process (calculate thresholds, find edge, and
period) are executed only if other measurements, such as fall time,
frequency, or delta time, are requested.
Calculating Top and Base
The next measurements made are the top and base of the waveform. These
measurements come directly from the histogram. The top 40 percent is
scanned for the top, and the bottom 40 percent of the histogram is scanned
for the base. The center portion of the histogram is not searched to prevent
a baseline value from being chosen as the top or base as shown in figure 13-4.
100%__._ ™ax
top
60%—
upper
mid “hysteresis
40%
lower
ox base
min
top/base will not find baseline
when search is restricted to
upper to max and lower to min
The middle 20 percent of the waveform is ignored
13-6