Atec Rohde-Schwarz-UPL - Manual (Page 14)

14 Audio Analyzer UPL
Fig. 16: Different signals for both channels may be generated
at the digital audio outputs
Low Distortion Generator UPL-B1
is essential for all applications requir-
ing extremely pure analog signals or
an extended frequency range up to
110 kHz. Its inherent distortion is well
below that of the built-in universal gen-
erator which already has excellent
specifications.
When digital audio data are pro-
duced by the universal generator, the
low distortion generator may generate
an analog signal or be used for super-
imposing jitter or common-mode inter-
ference.
Digital Interfaces UPL-B2/-B29
contain the digital audio interfaces
(balanced, unbalanced and optical)
for the standard sampling rates
44.1 kHz and 48 kHz, UPL-B29 also
for the extended rates up to 96 kHz.
Either UPL-B2 or UPL-B29 can be fitted.
For further information on options and
associated software extensions
(Digital Audio Protocol UPL-B21 and
Jitter and Interface Test UPL-B22) refer
to pages 8 and 9.
Audio Monitor UPL-B5
adds a headphones output and a built-
in loudspeaker to UPL. The input signal
of the analog and digital interfaces and
– with level, THD+N and rub & buzz
measurements – the filtered or
weighted signal can be monitored.
Fig. 15: Third-octave analysis used mainly in acoustics
Options and further applications
Fig. 13: Transfer and coherence function for determining the
transfer characteristic with the aid of complex test signals (eg
music or voice)
Fig. 14: Frequency response and rub & buzz function for qual-
ity assurance in loudspeaker production
Extended Analysis Functions UPL-B6
In modern audio systems, the transfer
characteristics are dynamically
adapted to the input signals. With con-
ventional, static test signals as input sig-
nals, the dynamic processes are not
activated and thus the signals cannot
be analyzed. Coherence and transfer
function are the solution to this prob-
lem: speech, music, noise, etc, are used
as test signals, and the transfer charac-
teristic is represented by analyzing the
output spectrum referred to the input
spectrum (Fig. 13). The required com-
plex test signals stored in various for-
mats can be directly called from the
UPL hard disk using the standard gen-
erator function Arbitrary.
With the rub & buzz measurement,
manufacturing defects of loudspeakers
can be found in no time by measuring
the unwanted signals in the frequency
range above that of typical distortion
products (Fig. 14).
The third-octave analysis is an impor-
tant measurement in acoustics. The lev-
els of up to 30 third-octave bands are
simultaneously measured in compli-
ance with class 0 of IEC1260
(Fig. 15).
In multitone signal generation, UPL-B6
allows also the phase and crest factor
to be set.
UPL-B6 is also required for generating
two-channel sinewave signals at the
digital outputs (Fig. 16).
Further functional extensions of UPL-B6
are under preparation.