HP 8590 E-Series User Manual page 340

frequency resolution
The ability of a spectrum analyzer to separate closely spaced spectral components and
display them individually. Resolution of equal amplitude components is determined by
resolution bandwidth. Resolution of unequal amplitude signals is determined by resolution
bandwidth and bandwidth selectivity.
frequency response
The peak-to-peak variation in the displayed signal amplitude over a specified center
frequency range. Frequency response is typically specified in terms of &dB relative to the
value midway between the extremes. It also may be specified relative to the calibrator
signal.
frequency span
The magnitude of the displayed frequency component. Span is represented by the
horizontal axis of the display. Generally, frequency span is given as the total span across the
full display. Some analyzers represent frequency span (scan width) as a per-division value.
frequency stability
The stability of a frequency component to remain unchanged in frequency or amplitude
over short- and long-term periods of time. Stability refers to the local oscillator's ability
to remain fixed at a particular frequency over time. The sweep ramp that tunes the local
oscillator influences where a signal appears on the display. Any long-term 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, and 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 spectrum analyzer scans the entire frequency band of an
analyzer.
function
The action or purpose which a specific item is intended to perform or serve. The spectrum
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
firmware 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 a spectrum analyzer where the displayed amplitude of
the signal is a specific number of dB too low due just to mixer saturation. The signal level
is generally specified for 1 dB or 0.5 dB compression and is usually between -3 dBm and
-10 dBm.
gated measurement
See time-gate.
hard copy
Information or data printed onto paper as opposed to its being stored on disk or in the
instrument's memory.
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