HP 54540 Series - Page 136

DEFINE HEAS
standard
user defined
+ Width
TT Mioth |
[trom edge #
‘ Tat mid
to Biedge #
2 at mid
Define Measure Menu
Define Measurement Menu
The upper threshold softkey and lower threshold softkey allows you to set
the upper and lower measurement thresholds. The upper and lower
thresholds must be set to levels that fall on the displayed waveform. The
message "not found" is displayed if either threshold is not on the waveform.
This feature is used when measuring excessive overshoot or ringing. By
defining the measurements, you can test for pass/fail criteria of any choice.
You can test from the front panel, or you can set the oscilloscope in the limit
test over HP-IB allowing the oscilloscope to collect measurement data
without supervision.
If time measurements are performed and the signal does not exceed 8 A/D
levels or 8 vertical pixel levels, the message "not found" is displayed in the
measurement area. Expand the signal vertically so the oscilloscope can make
the measurement.
Measurements The measurements selection allows you to further
customize the +width, -width, and Atime (delay) measurements. Width
measurements allow you to select the threshold (upper, middle, or
lower). Where these thresholds occur is defined by the thresholds
softkey.
The Atime choice allows you to select positive or negative slope, edge
number, and threshold (upper, middle, or lower). The oscilloscope starts
counting edges from the left edge of the screen, not at the reference point.
The selected edge must be displayed. If the edge is not displayed, the
message "not found" is displayed in the measurement results area below the
screen.
You can use Atime when measuring source-to-source delays or measuring
time separation on the same source or a different source. The Atime
measurement is defined by edge slope, edge count (from 1 to 4000), and the
part of the transition edge (upper, lower, mid) used as a reference point.
When setting edge count fields, use the fine key. In the coarse mode the
oscilloscope increments/decrements by ten (1, 11, 21,...,4000). In the fine
mode the increment/decrement sequence is by 1.
Because Atime measurements are made between two sources, the display
prompts you to select the source (c#, f#, m#) and the source number for each
source.
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