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random-access memory
RAM (random-access memory) or read-write memory, is a storage area
allowing access to any of its storage locations. Data can be written to or
retrieved from RAM, but data storage is only temporary. When the power
is removed, the information disappears. User-generated information
appearing on a display is RAM data.
raster display
A television-like display in which the image is formed by scanning the
electron beam rapidly across and slowly down the CRT face and gating
the beam on as appropriate. The scanning rates are fast enough to
produce a flicker-free display. Refer also to vector display and sweep
time.
read-only memory
ROM (read-only memory) that is encoded into the analyzer’s firmware.
The data can be accessed (read) only; it cannot be altered by the user.
reference level
The calibrated vertical position on the display used as a reference for
amplitude measurement in which the amplitude of one signal is compared
with the amplitude of another regardless of the absolute amplitude of
either.
relative amplitude accuracy
The uncertainty of an amplitude measurement in which the amplitude
of one signal is compared with the amplitude of another, regardless of
the absolute amplitude of either. Distortion measurements are relative
measurements, Contributors to uncertainty include frequency response
and display fidelity and changes of input attenuation, IF gain, scale factor,
and resolution bandwidth.
relative-marker mode
The active marker is positioned relative to the position of the reference
marker. Marker readout shows amplitude, frequency, or time differences
between the two markers.
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