NARDA IDA, Руководство по эксплуатации, Страница: 282 / 292

19 Glossary
274
IDA - 3106 Narda
RBW
R
esolution
b
and
w
idth
Resolution bandwidth
Signal selectivity.
Only signals having a frequency spacing that is
greater than the defined resolution bandwidth
can be distinguished from one another. The
RBW selected for measuring signals having
very close frequency spacing must be
correspondingly small. A larger resolution
bandwidth can be used for measuring wideband
signals.
• The indicated level will be too low if the RBW
is too small.
• Individual signals cannot be separated from
one another if the RBW is too big.
RL
R
eference Level
Reference Level
Parameter that determines the drive range and
sensitivity of the instrument. This parameter
sets the input attenuator among other things.
Signals below the reference level can be
measured without clipping. Smaller reference
levels reduce intrinsic noise and yields
increased sensitivity.
RMS
R
oot
M
ean
S
quare
Root Mean Square
The root mean square is an average value
formed by taking the square root of the average
of the sum of the squares of the individual
values, e.g. when measuring high frequency
electromagnetic fields. It corresponds to taking
the linear average of power densities.
Spectrogram Spectrogram A spectrogram is used to display the variation in
the signal strength of a spectrum versus time.
The recorded spectrums are shown as lines.
Different signal levels are represented by
different colors. This enables changes in the
spectral distribution to be seen rapidly.
Squelch Noise suppression Squelch is frequently used in walkie-talkies to
suppress the noise during pauses in speech
and transmission. The squelch threshold value
is settable.
Trace Measurement curve The trace display can be altered using
arithmetical functions. Depending on the
selected trace type, minimum or maximum
values can be held, or curves averaged. The
number of data points is not changed by this.
USB
U
pper
S
ide
B
and
Upper side band
The higher of the two sidebands that occur
through amplitude modulation.
Term or
Abbreviation
Meaning Function / Explanation