HP 8591C User Manual page 346

Any analyzer programming command having the distinct function of
returning a response. These commands may end with a question mark
analyzer display.
quiet line
A horizontal line with no video modulation used when performing
non-interfering measurements of carrier-to-noise and CSO.
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.
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.
real number
A positive or negative number with both a decimal and a fractional part.
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.
reference trace
The trace previously taken and later compared to the currently displayed
trace. For example, a trace taken at the headend for system frequency
response measurements.
resolution
Refer to frequency resolution.
resolution bandwidth
The ability of an analyzer to display adjacent responses discretely
(hertz, hertz decibel down). This term is used to identify the width of
the resolution bandwidth Elter of an analyzer at some level below the
minimum insertion-loss point (maximum deflection point on the display).
I -
Glossary- 13