R3267 Series Spectrum Analyzer Operation Manual (Vol.1)
A.3 Glossary
A-12
Figure A-5 Occupied Bandwidth
Quasi Peak Value Measurements
Reception interference for wireless communication generally occurs as impulse noise. Interference due to
noise energy is evaluated in proportion to the quasi peak value. The parameters required for this evaluation,
such as measurement bandwidth, detection time constant and so on, are defined as the quasi peak value.
There are two standards which affect this sort of measurement: JRTC for Japan only, and CISPR (Interna-
tional Special Committee on Radio Interference) which applies internationally.
Residual FM
The short-term frequency stability of the local oscillators built in the spectrum analyzer is expressed as re-
sidual FM. The frequency width fluctuating per unit time is expressed as p-p. This also determines the mea-
surement limit value when measuring the residual FM of a signal.
Residual Response
Residual response is a measure of how much (in the input level calculation) the spurious signal generated by
the spectrum analyzer is suppressed. Residual response is generated by leaks of signals such as local oscilla-
tion output in the spectrum analyzer. This should be taken into consideration when analyzing a low-level in-
put signal.
Resolution Bandwidth
The spectrum analyzer uses the bandpass filter (BPF) to analyze the frequency components contained in the
input signal. The 3dB bandwidth of the BPF is called the resolution bandwidth (See Figure A-6(a) below).
BPF characteristics should be set according to the sweep width and the sweep speed used for the trace. This
spectrum analyzer sets the optimal value for the sweep width. In general, smaller bandwidths improve reso-
lution so the resolution of the spectrum analyzer should be expressed using the narrowest resolution band-
width (See Figure A-6(b) below).
P=0.5%
P=0.5%
P=99%
am
p
litu
d
e
FU
FL
Frequency
0
0
Occupied Bandwidth
