HP 8590 E-Series User Manual page 338

detector mode
The manner in which analog, video information is processed prior to being digitized and
stored in memory. Refer also to negative peak, positive peak, quasi-peak detector,
rosenfell, and sample.
digital display
A display that uses vectors drawn between a series of data points (analog video) that are
first digitized and stored in memory, then displayed. The number of stored data points is a
function of the particular analyzer. The displayed information is refreshed (old data points
are replaced with new data points stored in memory) at a flicker-free rate. The data in
memory is updated at the sweep rate of the analyzer.
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
dB/division, 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 a spectrum analyzer.
On purely analog analyzers (those analyzers that display trace information immediately and
do not store, then recall the data to the screen), these differences are displayed on the
screen and the graticule is used to evaluate the measurement. Many analyzers with digital
displays (refer to digital display) have markers that can be used to measure the signal. As a
result, measurement differences are stored in memory, and the ambiguity of the display is
eliminated from the measurement.
display range
The calibrated range of the display for a particular display mode or scale factor. Refer also
to linear display, log display, and scale factor.
displayed average noise level
The noise level viewed on the analyzer's display after narrowing the video bandwidth
setting enough to reduce the peak-to-peak noise fluctuations. The resulting noise display
is essentially a straight line. Usually this term refers to the analyzer's own internally
generated noise as a measure of sensitivity. It is typically specified in dBm under conditions
of minimum resolution bandwidth and minimum input attenuation.
DLP
The abbreviation for downloadable program. A single programming command or a sequence
of programming commands used to perform specific operations. DLPs can be made up
of several functions, variables, and traces defined by the program creator. The DLP can
be downloaded from one electronic storage medium into another and executed without a
controller.
drift
The slow (relative to sweep time) change of signal position on the display as a result of a
change in local oscillator frequency versus sweep voltage. While analyzer drift may require
periodic retuning, it does not impair frequency resolution.
dynamic range
The power ratio (dB) between the smallest and largest signals simultaneously present at the
input of an analyzer that can be measured with some degree of accuracy. Dynamic range
generally refers to measurement of distortion or intermodulation products.
Glossary-4