Rohde & Schwarz R&S UPP, User Manual

Page: 404 / 938

Instrument Functions
R&S
®
UPP
388 User Manual 1411.1055.32 ─ 10
"Auto" The fundamental frequency is determined (separately for each chan-
nel) by means of internal frequency measurement.
Recommended for use with an external signal source.
"Value " Fixed fundamental frequency; the value must be entered in the
parameter field below.
Recommended for signals with a high noise component if an external
generator is used as the signal source.
"Gen Track" The fundamental frequency changes with the generator (nominal) fre-
quency. This can be changed by means of manual entry in the Gener-
ator Function panel or owing to a generator frequency sweep. Setting
reliability in the case of signals with a high noise component is thus
improved and measurement speed is increased.
An error message is output if an unsuitable signal function is selected
in the generator (e.g. a multi-tone signal or noise signal).
Recommended when using the internal universal generator.
Remote command:
SENSe[1]:VOLTage:FUNDamental:MODE
on page 760
SENSe[1]:VOLTage:FUNDamental
on page 759
Refinement
Improvement of the signal-to-noise ratio
"1" The refinement factor 1 is suitable for the THD measurement on sig-
nals with good S/N ratio.
"2, 4, 8"
With an adverse S/N ratio and low total harmonic distortion, the noise
signal can receive a higher level than the distortion product in the
analysis bandwidth, thereby leading to hardly any informative mea-
surement results. With the refinement factors 2, 4 or 8, the analysis
bandwidth is reduced accordingly, thereby increasing the frequency
resolution, which leads to an improvement in the S/N ratio in incre-
ments of 3 dB each.
Remote command:
SENSe[1]:FUNCtion:REFNment
on page 758
Distortion Measurements