User`s guide

measurement units
Trace information is stored in trace arrays made up of measurement units. The
measurement-unit range is restricted to integers between -32,768 and +32,767. In
a logarithmic scale, a measurement unit is one-hundredth of a dBm, or represented
mathematically as: (value in dBm) x 100 = measurement units. As an example,
-10.115 dBm x 100 = -1012 measurement units, not -1011.5. Measurement units for
linear-trace information are from zero, for the bottom of the display, to 10,000 for the top
of the display, or the reference level.
memory
A storage medium, device, or recording medium into which data can be stored and held
until some later time, and from which the entire original data may be retrieved.
memory card
A small, credit-card-shaped memory device that can store data or programs. The programs
are sometimes called personalities and give additional capabilities to your instrument.
Typically, there is only one personality per memory card. Refer also to personality.
menu
The spectrum analyzer functions that appear on the display and are selected by pressing
front-panel keys. These selections may evoke a series of other related functions that
establish groups called menus.
narrowband response
A response measured under conditions in which there is only one spectral component
at a time in the passband of a spectrum analyzer’s resolution filter. This condition occurs
for continuous wave signals and repetitive signals whose repetition rate is greater than
about twice the resolution bandwidth of the analyzer. Note that a signal can have a spread
spectrum and still be viewed in the narrowband mode on the spectrum analyzer. The same
checks that were listed under broadband response are used here but with different results:
n Change the frequency span. The frequency separation of the components remains
unchanged.
n Change the resolution bandwidth. The amplitude of the responses does not change with
resolution bandwidth changes (as long as the bandwidth remains narrow relative to the
separation of the responses).
n Change the sweep time. The separation of the responses is independent of sweep time.
n Change the video bandwidth. The amplitude of the responses is unaffected by changes in
video bandwidth.
negative peak
The minimum, instantaneous value of an incoming signal. On digital displays, each
displayed point of the signal indicates the minimum value of the signal for that part of the
frequency span or time interval represented by the point.
noise figure
The ratio, usually expressed in dB, of the signal-to-noise ratio at the input of a device
(mixer, amplifier, and so on) to the signal-to-noise ratio at the output of the device.
noise marker
A marker whose readout represents the noise level in a 1 Hz noise power bandwidth. When
the noise marker is selected, the sample display detection mode is activated, the values
of a number of consecutive trace points about the marker (the number depends on the
type of analyzer) are averaged, and this average value is normalized to an equivalent value
in a 1 Hz noise power bandwidth. The normalization process accounts for detection and
bandwidth plus the effect of the log amplifier when we select the log-display mode.
Glossary-l II