HP 8591C User Manual page 341

variation in local oscillator frequency (drift) with respect to the sweep
ramp causes a signal to shift its horizontal position on the display slowly.
Shorter-term local oscillator instability can appear as random FM or phase
noise on an otherwise stable signal.
front-panel key
Keys, typically labeled, located on the front panel of an instrument. The
key labels identify the function the key activities. Numeric keys and step
keys are two examples of front-panel keys.
full span
A mode of operation in which the analyzer scans the entire frequency
band of an analyzer.
function
The action or purpose that a speciEc item is intended to perform or serve.
The analyzer contains functions that can be executed via front-panel key
selections, or through programming commands. The characteristics of
these functions are determined by the Ermware in the instrument. In
some cases, a DLP (downloadable program) execution of a function allows
you to execute the function from front-panel key selections.
gain compression
The signal level at the input mixer of an analyzer where the displayed
amplitude of the signal is a speciEc number of dB too low due just to
mixer saturation. The signal level is generally speciEed for 1 dB or 0.5 dB
compression and is usually between -3 dBm and -10 dBm.
gated measurements
The tests requiring Option 107 that allow carrier-to-noise, CSO, and
in-channel frequency response measurements to be performed without
disrupting service.
hard copy
Information or data printed onto paper as opposed to its being stored on
disk or in the instrument's memory.
Pushbutton keys on the analyzer front panel that control frequency, span,
amplitude, instrument state, markers, controls, and data functions.
Glossary8