HP 8591C, User Manual, Page: 338 / 373

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current trace
The displayed trace on the analyzer screen.
default
The preset conditions, options, or parameters of an instrument. The
default state may be changed by choosing key selections or writing
programming commands to use other conditions.
delta marker
An analyzer mode in which a fixed reference marker is established, then
a second active marker becomes available so it can be placed anywhere
along the trace. A readout indicates the relative frequency separation and
amplitude difference between the reference and active markers.
depth of modulation
Measures the percentage of amplitude modulation on the video carrier
between the horizontal synchronization-pulse and the vertical interval test
signal white level.
differential gain
This is the change in amplitude of the chrominance subcarrier as the
luminance changes from a blanking level towards white level. It is
measured as the difference in amplitude between the largest and smallest
segments, divided by the largest and expressed in percent.
differential phase
As by the NTC, this is the maximum peak-to-peak change in
phase of the chrominance subcarrier as the luminance changes from a
blanking level towards white level.
As by the FCC, the greatest phase difference in degrees between
each segment of the chrominance signal and the reference signal.
display dynamic range
The maximum dynamic range over which both the larger and smaller
signal can be viewed simultaneously on the display. For analyzers with a
maximum logarithmic display of 10 the actual dynamic range
may be greater than the display dynamic range. Refer also to dynamic
range.
display fidelity
The measurement uncertainty of relative differences in amplitude on an
analyzer. On purely analog analyzers (those analyzers that display trace
Glossary-5