Atec UPL User Manual

Audio Analyzer UPL

T h e solution for the budget-conscious

• For all interfaces:
analog, digital and combined

• Real dual-channel measure­ments

• Maximum dynamic range

• FFT analysis

• Jitter analysis

• Interface tester

• Freely programmable filters

• Versatile functions

• Compact unit with integrated PC

• Automatic test sequences

• Extensive online help

Audio analysis today and tomorrow

Analog and digital

Audio signal processing is nowadays
no longer conceivable without the use
of digital techniques. Yet, analog tech­nology continues to exist and under­goes constant improvement. State-of­the-art measuring instruments must
therefore be able to handle both ana­log and digital signal processing.

Audio Analyzer UPL performs practi­cally all types of analog measurement,
from frequency response measure­ments through to externally controlled
sweeps with reference traces, determi­nation of 3rd-order difference fre­quency distortion, spectral display of
demodulated wow and flutter signals,
etc. In contrast to many other audio

analyzers, UPL is capable of perform­ing real dual-channel measurements in
the audio-frequency range, ie there is
no need for switch-over between two
inputs and this type of measurement is
not limited to a few special cases.

The generator is every bit as versatile:
it supplies any conceivable signal from
sinewave and noise signals through to
multi-sinewave signals comprising up to
7400 frequencies.

In addition to all this, UPL features
excellent technical data: analog sine­wave generation with harmonics of
typ. −120 dB, spectrum displays with
a noise floor below −140 dB for ana­log and −160 dB for digital interfaces,
FFT with a maximum frequency resolu­tion of 0.05 Hz, etc.

UPL provides signal monitoring via
loudspeaker, jitter measurements on
digital audio signals, resynchroniza­tion of jittered digital audio signals by
means of a jitter-free clock signal, and
many more features.

Superior analysis concept

UPL performs all measurements using
digital signal processing. Analog sig­nals to be tested undergo elaborate
preprocessing before they are digi­tized and measured by means of dig­ital routines. For example, in THD
measurements, the fundamental is
attenuated by means of a notch filter
and the residual signal amplified by
30 dB before it is digitized. In this way,
the dynamic range can be extended

2 Audio Analyzer UPL

2 Audio Analyzer UPL

beyond that offered by the internal
20-bit converter. This provides suffi­cient margin for measuring converters
of the future, which will be technically
more advanced than those of present­day technology (see graph below). This
concept guarantees performance and
flexibility by far superior to instruments
providing purely analog or digital
measurements.

Performance

Purely
digital

measurements measurements

Purely

analog

• The filters, too, are implemented
digitally, resulting in an infinite
number of filters as it were, and
this also for measurements on ana­log interfaces. Simply choose the
type of filter (eg highpass), cutoff
frequency and attenuation: that’s
all you have to do to loop a new
filter into the test path

Digital

analysis

and analog

preprocessing

A future-proof investment

Nobody can accurately predict today
what effects future developments in dig­ital technology will have on the audio
world and what will be the resulting test
requirements. This is however no prob­lem for Audio Analyzer UPL. Since all
test functions are implemented digitally,
UPL can be adapted to changing
requirements by simply loading the
necessary software – and this also for
the analog interfaces.

And one more thing: Rohde & Schwarz
is the only manufacturer to equip its
audio analyzers with 32-bit floating­point signal processors throughout,
thus offering plenty of reserves beyond
the limits of today’s common 24-bit
technology.

The intelligent combination of analog and digital measurement
techniques paves the way for future applications

The above measurement concept offers
many other advantages over merely
analog concepts:

• In intermodulation measurements,
spurious components are mea­sured selectively for all frequencies
in accordance with the mathemati-

• The test routines for analog and
digital interfaces are identical. This
allows, for instance, the direct
comparison of IMD measurements
made ahead of and after a con­verter

• All test functions are available both
on the analog and the digital inter­faces. This makes it possible to
measure at any point of a common
analog and digital transmission
path. Only this ensures efficient
and complete testing

cal formula of the relevant test
standards. This procedure avoids
the measurement of adjacent com­ponents along with the spuria,
which is usually inevitable with an­alog test methods

• Measurement speed is as a rule
higher than with analog techniques
since digital test routines can
adapt their speed to the input fre­quency. And – last but not least:

• Operation is the same for the ana­log and the digital interfaces. A
feature that should not be under­estimated

Certified Quality System

ISO 9001

DQS REG. NO 1954-04

A competent partner

The name of Rohde & Schwarz stands
for excellent quality – thousands of
audio analyzers have proven records
at satisfied customers and have been in
operation successfully for many years.
After the purely analog UPA and UPD,
which still holds the top position in
today’s audio measurement technology,
Audio Analyzer UPL has been devel­oped to complete the product line.

As a competent partner we shall be
pleased to advise you on the optimum
use of our instruments. Our representa­tives are available for you all over the
world, and our customer support center
and application engineers in Munich
help you find the right solution to your
measurement tasks. In addition, you
will find a wealth of proposals and
solutions in our application notes and
software.

Naturally, Rohde & Schwarz instru­ments are certified in compliance with
ISO 9001 and ISO 14001.

Audio Analyzer UPL 3

Fig. 1: Automatic marking of harmonics in THD+N measure­ments makes nonharmonics visible at a glance

Fig. 2: In THD measurements, single harmonics, all harmonics
or any combination of harmonics can be measured

Fig. 3: The waveform function displays the test signal in the
time domain. The example shows a sinewave burst

Fig. 4: The transient characteristics of an AGC play an impor­tant role in testing hearing aids or automatic volume control on
tape recorders

Test signals – as you like it

The generators of UPL supply an

extremely wide variety of analog and –
with options UPL-B2 or UPL-B29 –
digital test signals:

• Sinewaves
for level and harmonic distortion
measurements. The signal can be
applied to an equalizer with user­selectable nominal frequency re­sponse, eg for compensating the
frequency response of the test as­sembly

• Two-tone signal
for modulation distortion analysis.
Various amplitude ratios can be se­lected and the frequencies are con­tinuously adjustable

• Difference tone signal
for intermodulation measurements
with continuous setting of both fre­quencies

• Multitone signal
comprising up to 17 sinewaves of
any frequency and with the same
or different amplitude; setting the
phase is also possible with UPL-B6

• Sine burst signal
with adjustable interval and on­time as well as programmable low
level, eg for testing AGCs

2

• Sine

• Special multitone signal

burst

also with adjustable interval and
on-time, eg for testing rms rectifier
circuits

comprising up to 7400 frequencies
with selectable amplitude distribu­tion. The frequency spacing can be
linked to the resolution used for the
fast Fourier transform, thus en­abling rapid and precise single­shot measurements of the frequen­cy response of a DUT

An allrounder

• Noise

with a variety of probability distri­butions, eg for acoustic measure­ments; setting of crest factor with
UPL-B6

• Arbitrary waveforms

for generating any voltage curve
of up to 16k points. Test signals
can be output in different file for­mats, eg voice and music signals
stored as WAV files

• Two-channel sinewave signals

for the two digital output channels
when UPL-B6 is used

• AM and FM

for sinewave signals

• DC

also with sweep function

Signals can be generated with an
offset. Moreover, digital audio signals
can be dithered with adjustable level
and selectable amplitude distribution.

4 Audio Analyzer UPL

Versatile test functions

UPL offers a wealth of measurement

functions both for analog and – with
option UPL-B2/-B29 – for digital inter­faces.

• Level or S/N

with rms, peak or quasi-peak
weighting;
high measurement speeds due to
automatic adaptation of integra­tion times to input signal

• Selective level
The center frequency of the band­pass filter can be swept or coupled
to the generator frequency, to the
frequencies of a multitone signal (eg
for fast frequency response mea­surements) or to the input signal

• SINAD or THD+N
The sum of all harmonics and noise
is measured (Fig. 1)

• Total harmonic distortion (THD)
Individual harmonics, all the har­monics or any combination of har­monics can be measured (Fig. 2)

• Modulation distortion

to DIN-IEC 268-3. 2nd and 3rd or­der intermodulation is measured

• Intermodulation

using the difference tone method.
2nd and 3rd order intermodulation
is measured

• Wow and flutter

to DIN IEC, NAB, JIS or the
2-sigma method to DIN IEC where
the demodulated-signal spectrum is
also displayed

• DC voltage

• Frequency, phase and group delay

• Polarity

Signal paths are checked for
reversed polarity

• Crosstalk

• Waveform function

for representing the test signal in the
time domain (Fig. 3). Waveforms
can be smoothed by interpolation.
Slow sequences can be displayed
compressed, eg for analyzing the
transient response of compander or
AGC circuits (Fig. 4)

•

Extended Analysis Functions
UPL-B6:
coherence and transfer functions

for determining the transfer charac­teristics of complex test signals;

third octave analysis

mainly for

acoustic measurements;

rub & buzz

measurements in loud-

speaker production

Tests on hi-fi components call for increasingly complex measurement techniques. Results
obtained in the test lab must be verified in production, where as a rule not the whole range
of test functions is needed but economical solutions to cater for large batches. UPL is an

ideal choice for this task. It optimally complements its “bigger brother“, Audio Analyzer
UPD, which is mainly employed in development. The operating concept of the two units
based on the same IEC/IEEE-bus commands is identical, so there is no problem using them
jointly

Audio Analyzer UPL 5

All-in package

Fig. 5: FFT spectrum of two-tone signal shown on full screen

Fig. 6: With the zoom FFT function, sidebands spaced only a
few hertz from the signal can be displayed

Fig. 7: Filters can be defined by entering just a few
parameters

Spectrum analysis

With its FFT analyzer, UPL is also capa­ble of spectrum analysis. The number of
samples for fast Fourier transform can
be selected between 256 and 16k in
binary steps (Fig. 5). A special feature
is zoom FFT. The signal to be measured
is digitally preprocessed to increase the
frequency resolution by a factor of 2 to
128 over a selectable range. In this
way, a maximum resolution of 0.05 Hz
is attained. It should be emphasized
that this is not just a scale expansion
but the measurement is really made at
a higher resolution (Fig. 6).

Programmable filters

The filters of UPL are software-imple­mented so that the user can define any
number of filters. The most common
weighting filters are provided as
standard. Further filters can be pro­grammed in a few seconds by enter­ing the type (lowpass, highpass, band­pass, bandstop, notch, third octave or
octave), frequency and attenuation

(Fig. 7). The instrument’s open archi­tecture shows its strength in particular
where special requirements have to be
met: special filters can be imple­mented using commercial filter design
programs. The data are transferred to
UPL and the created filter is looped
into the signal path.

A variety of sweep functions

For continuous variation of the test
signals, UPL offers amplitude and fre­quency sweeps and for bursts addi­tionally sweeps of interval and on­time. Sweeps are defined either by
means of a table or via parameters
such as start value, number of steps,
linear/ log stepping or time interval. It
is also possible to sweep two variab­les simultaneously.

In measurements of external signals,
these can be used for analyzer sweeps
(external sweeps). Many different start
conditions can be set, allowing mea­surements to be triggered by a variety
of events. Results will be stable even
for DUTs with unknown or unstable
transient response thanks to the
settling function.

Fig. 8: Tolerance curves enable fast go/nogo tests

6 Audio Analyzer UPL

The strengths of UPL
show up especially in
mobile use. The unit is
compact and light­weight and requires no
additional equipment.
Results are stored in the
built-in PC and thus
available for later use.
Routine measurements
can be repeated easily
using stored instrument
settings

Audio Analyzer UPL is a compact unit
with an integrated controller. It avoids
the disadvantages of external PC con­trol, which is found in other audio ana­lyzers.

The instrument is easy to transport as it
requires no external equipment such
as keyboard, monitor or other PC
peripherals.

UPL features elaborate screening such
as magnetically shielded power trans­formers and coated filter pane in front
of the display.

And a real boon: the price of UPL
includes the internal PC.

• Built-in hard disk and disk drive

• Connectors for keyboard, mouse,
monitor, printer and plotter

• Centronics interface for connecting
printer or network

• Drivers for commercial printers are
supplied as standard

• Remote control via IEC/IEEE bus or
RS-232-C interface

• Postprocessing of results directly in
UPL using standard software

• All results available in the common
data formats, making it easy to im­port graphics into documents, for
example

• Easy loading of function and soft­ware extensions via floppy disk

• Automatic test sequences and mea­surement programs with universal
sequence controller. Easy genera­tion of programs with built-in pro­gram generator

UPL is supplied ready for use. Installa­tion is nothing more than unpacking
the unit and switching it on for starting
the measurement. The user is not bur­dened with problems that cropped up
in the past with the installation of inter­face cards or PC software.

With audio analyzers controlled from
an external PC, interference may be
radiated from the PC, monitor or inter­face connections, which distorts mea­surement results. Not so with UPL: the
instrument has specified EMC charac­teristics which also include the internal
PC. In contrast to conventional PCs,

Audio
monitor
(option)

Balanced

Analog

pre-

processing

Analyzers

Disk

drive

Centronics

Digital

analysis

Hard disk

RS-232-C

Unbalanced

Optical

Balanced

Reference

Sync

Sync

Digital I/Os (option)

Software options:

- digital interface analysis

- digital protocol analysis

- automatic sequence controller

- extended analysis functions

External keyboard External monitor

RS-232-C

Reference

Optical

Unbalanced

Balanced

Digital

signal

generation

Block diagram of UPL

Balanced

Low distortion

Analog
outputs

Generators

generator

(option)

IEC/IEEE

bus

(option)

Audio Analyzer UPL 7

Interfaces, protocol analysis, jitter

Fig. 9: Individual interference components can easily be
found with the aid of the jitter spectrum

Fig. 10: Display of jitter signal in time domain

Fig. 11: Complete measured-value tables can be output for
all functions

Fig. 12: UPL generates and analyzes additional data in digi­tal data streams in line with all common standards. The data
are represented in binary form, as hexadecimal numbers, as
ASCII characters or evaluated in consumer or professional
format

Analog interfaces

• Balanced inputs with high common­mode rejection and various imped­ances commonly used in the studio.
Measurements can be made on
lines with phantom feed

• Balanced outputs, floating (eg to
prevent hum loops)

• The generator outputs can be inter­nally connected to the analyzer
inputs so that different types of
measurement can be made without
the need for changing the cabling

Digital audio interfaces
(options UPL-B2 and UPL-B29)

• Balanced (XLR), unbalanced (BNC)
and optical (TOSLINK) inputs and
outputs for connecting consumer
electronics and professional studio
equipment

• The levels of the balanced and un­balanced outputs are adjustable so
that the sensitivity of digital audio
inputs can be determined

• The format of the generated chan­nel status data may be profession­al or consumer irrespective of the
selected interface

• A reference (XLR) and a synchroni­zation (BNC) input provided on the
rear panel allow both the analyzer
and the generator to be synchro­nized to the digital audio reference
signal (DARS) to AES 11, and the
generator in addition to word­clock, video sync signals (PAL/
SECAM/NTSC) and to 1024 kHz
reference clocks

• Both generator and analyzer can
be driven at clock rates of 35 kHz
to 106 kHz. The clock signal can
also be produced internally by the
generator

• The clock rates of the analyzer and
generator are independent of each
other. This allows measurements on
sample rate converters

• The word length can be selected
between 8 and 24 bits independ­ently for generator and analyzer

Improvement of audio quality of sound cards and multi-

media equipment – a task for UPL

Digital protocol analysis and
generation (option UPL-B21)

This software option extends the func­tions of options UPL-B2 and UPL-B29 by
an in-depth analysis and generation of
additional digital data:

• Analysis of channel status and user
data. The data are output in binary
form, as hexadecimal numbers, as
ASCII characters or, in the case of
channel status data, evaluated in
the professional or consumer for­mat to AES 3 or IEC 958 (Fig. 12)

8 Audio Analyzer UPL