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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