Rohde & Schwarz R&S UPP, Руководство пользователя

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Instrument Functions
R&S
®
UPP
381 User Manual 1411.1055.32 ─ 10
For more settings, see Chapter 5.21, "Level Measurements" , on page 359.
S/N Sequence
Used for activating the S/N sequence in order to determine the signal to noise.
Signal-to-noise measurement can thus be performed in the "RMS" and "Peak" level
measurement modes.
"deactivated" The S/N sequence is disabled.
A pure level measurement is carried out.
"activated" The S/N sequence is enabled
Level measurement is performed with the generator signal switched
on and then with it switched off. The S/N measurement result is deter-
mined from this.
Remote command:
SENSe[1]:FUNCtion:SNSequence
on page 757
5.23 Distortion Measurements
The R&S UPP provides various methods for measuring distortions. These methods
can be used to determine harmonic or intermodulation distortions of a DUT.
The measurement signals required in each case can be generated by the internal gen-
erator (recommended) or by an external signal source.
●
THD (total harmonic distortion) is a distortion measurement over the first 8 harmon-
ics or over any given combination of the first 8 harmonics. The noise between the
harmonics is not measured. An ultra-pure sine-wave signal is required as the mea-
surement signal.
●
THD+N & SINAD (total harmonic dist noise) is a distortion measurement
that measures the energy of the broadband noise and (optionally) of all harmonics
within a selectable frequency band. An ultra-pure sine-wave signal is required as
the measurement signal.
●
Mod Dist is a modulation factor analysis that determines the total intermodulation
factor of the 2nd and 3rd order of a low-frequency interfering signal to a high-fre-
quency useful signal. The interfering signal should have the same or a higher
amplitude than the useful signal (preferably an amplitude ratio of 4
: 1).
●
DFD is a difference-tone factor analysis that determines the 2nd and 3rd order
intermodulation products generated by two sine-wave signals of the same ampli-
tude.
The individual distortion components can be assessed visually using the bar graph or
(Post) FFT, see also
Chapter 5.26.3, "Post FFT" , on page 411.
The measured values can only have the full dynamic range if both the signal source
and the analyzer are at full-scale level. If the measured values are worse than expec-
ted, the following rules should be checked and observed.
Distortion Measurements