Atec Agilent-U8903A User Manual
Capabilities
• Select generator, analyzer,
graph, and sweep modes with
one-button access
• Measure at DC and from 10 Hz
to 100 kHz
Agilent U8903A Audio Analyzer
Make an Audible Difference
Data Sheet
• Characterize signal-to-noise
ratio, SINAD, IMD, DFD,
THD+N ratio, THD+N level,
crosstalk, and more
• Apply weighting functions,
standard filters, and custom
filters
• Stimulate the device with
high-quality signals and
arbitrary waveforms
• View numerical and graphical
displays of measurement
results
• Connect to a PC through
GPIB, LAN/LXI C, and USB
interfaces
• Code compatible with
HP8903B
• 2 in 1 screen (generator and
analyzer in the same display
screen)
Whether listening to mono, stereo, or surround, the human ear knows what
sounds good. Measuring “how good,” however, can be a challenge. The Agilent
U8903A audio analyzer helps you measure and quantify audio performance in
applications such as wireless audio, analog components and ICs, and consumer
audio.
Across the audio spectrum and beyond, this scalable, single-unit solution
provides versatile measurement functions, diverse test signals, and powerful
analysis capabilities.
The U8903A audio analyzer combines the functionality of a distortion meter,
SINAD meter, frequency counter, AC voltmeter, DC voltmeter, and FFT analyzer
with a low-distortion audio source. On the bench or in a test system, its accuracy and versatility helps you make an audible difference in your end product.
LXI class C certified
Replace your 8903B and add
next-generation capabilities
For nearly two decades, the HP 8903B
provided unparalleled versatility and
performance in audio applications.
The U8903A builds on the legacy of
the 8903B by offering faster singlepoint measurements (0.4 sec versus
3.0 sec) as well as a wider frequency
range, expanded performance, and
greater functionality (Tables 1, 2, and
3). With the U8903A, you can configure measurements faster through
its graphical user interface (GUI)
and one-button selection of major
operating modes. The color screen
lets you view dual-parameter displays
from one or two channels as well
as graphical displays of sweeps, frequency spectra, and more (Figure1).
To makes the transition easy, the
next-generation replacement for the
HP 8903B audio analyzer features
a built-in code emulator which
automatically converts 8903B R2D2
code directly into SCPI commands
used by the U8903A. The Agilent
application note Migrating Code from
the 8903B to U8903A (5990-4135EN)
and the U8903A Programming Guide
(U8903-90027) provide additional
resources to assure you get the most
from this new class of audio analyzer.
Table 1. Comparison of frequency range and accuracy
U8903A HP 8903B
Frequency range DC and 10 Hz to 100 kHz 20 Hz to 100 kHz
Frequency accuracy 5 ppm (0.0005%) 0.004%
Table 2. Comparison of accuracy and ranges in AC and DC level measurements
U8903A HP 8903B
AC voltage input range 0 V to 140 V
AC accuracy ± 1% ± 4%
DC voltage input range 0 to ± 200 V 4 to 300 V
DC accuracy ± 1% ± 1%
Table 3. Comparison of range and residual THD+N measurements
rms
0.3 mV
to 300 V
rms
U8903A HP 8903B
Frequency range 10 Hz to 100 kHz 20 Hz to 100 kHz
),
Residual THD+N
(signal distortion)
at 80 kHz BW
Accuracy ± 0.5 dB (< 20 kHz)
≤ –101 dB (at 1 kHz, 1 V
20 Hz to 20 kHz
± 0.7 dB (< 100 kHz)
rms
–80 dB (or 15 µV),
20 Hz to 20 kHz
± 1 dB (20 Hz to 20 kHz)
± 2 dB (20 to 100 kHz)
rms
Figure 1. The new U8903A audio analyzer (left) offers numerous improvements over the widely used HP 8903B (right).
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Address Challenging Audio Applications
Measure and analyze essential
audio parameters
With the U8903A, you can measure
below, across, and above the audio
spectrum with its 10 Hz to 100 kHz
frequency range and built-in DC measurements. Its dual input channels let
you perform stereo audio, frequency
response, wireless and component
tests—all at a single-channel price.
Easily characterize parameters such
as signal-to-noise ratio, SINAD,
intermodulation distortion (IMD),
different-frequency distortion (DFD),
total harmonic distortion (THD+N
ratio, THD+N level), crosstalk, and
more. Additional measurement
capabilities include AC level, DC level,
frequency count, frequency spectrum,
and FFT analysis (Figure 2).
For all measurements, you can
apply weighting functions as well as
low-pass, high-pass, and standard
filters (Figure 3). You can also create
custom filters using MATLAB® and
other applications, and upload them
through the analyzer’s USB port.
Filters and weighting functions can be
applied one, two, or three at a time.
U8903A also provides a 2 in 1 screen,
which simultaneously displays the
generator and analyzer information
(Figure5). This allows the user to
change the generator (source) setting
while monitoring the analyzer results
in real time.
Generate high-quality test
signals
The built-in, dual-channel signal generator lets you stimulate your device
with a variety of high-quality signals:
sine (–105 dB noise floor), square,
rectangular, noise (Gaussian and
rectangular), two-tone, and multi-tone
(up to 60) (Figure4). To simulate com-
plex and real-world signals, you can
also create arbitrary waveforms with
up to 16,384 points and at 312.5kHz
sampling rate.
The output voltage range is 0 V to
8 V
with 1% accuracy. For unbal-
rms
anced connections, you can select
50 or 600 Ω output impedance.
Easily perform manual and
automated tests
One-button access makes it easy
to select the four main operating
modes: analyzer, generator, graph,
and sweep. The 5.7-inch color display
provides numeric readouts as well as
graphical views of analog sweeps,
FFT spectra, and more.
For PC-based control on the bench
or in a test system, the U8903A
includes GPIB, LAN/LXI C, and USB
interfaces.
Figure 2. Perform FFT analysis with up to
32 Kpoints and a wide selection of
informative graphing functions
Figure 4. Utilize high-quality test signals that provide low distortion and low noise level
Figure 3. Apply an extensive selection of
filters, including a variety of weighting
functions
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Figure 5. 2 in 1 screen generator and
analyzer in the same display screen
Take a Closer Look
Front panel
One-button access to
analyzer, generator,
and sweep modes
Quick buttons for
graphical analysis
Front-panel output
on/off button for
DUT protection
Plug-and-play
USB 2.0
connectivity
5.7-inch color
display
Figure 6. U8903A audio analyzer, front view
Rear panel
Softkeys for easy
function selection
Dual-channel generator
outputs and analyzer inputs
with XLR connectors
Figure 7. U8903A audio analyzer, rear view
GPIB, LAN/LXI C,
and USB interfaces
4
Advance Measurement Testing
General audio testing
The U8903A provides essential
measurement capabilities that enable
efficient analysis of audio amplifiers
and other devices in the audio chain.
For example, the analyzer includes
balanced and unbalanced outputs
and inputs. It also provides a wide
selection of filters and enhances your
flexibility by making it easy to upload
customized filters. With an array of
sweep functions and flexible data
display formats for each measurement, you’ll be ready to address
a wide range of challenging audio
applications.
Balanced inputs
In the quest for higher output power,
many audio amplifiers use bridged
output stages. Such amplifiers can be
difficult to characterize because their
outputs cannot be grounded. To test
these devices, the usual approach
has been to use a balanced, calibrated isolation transformer connected to
an analyzer with an unbalanced input.
The widely used HP 8903B eliminated
the need for a transformer, but it was
still necessary to float the analyzer
input before connecting the bridged
device and making measurements.
With the U8903A, you simply make
a balanced connection with an
XLR connector and make measurements—no floating required.
analyzer’s USB port. The U8903A also
includes selectable 15, 20, and 30kHz
low-pass filters to reject unwanted,
out-of-band signals and noise.
Display scaling and formatting
U8903A gives you flexible control
over data displays. For example, you
can choose volts, millivolts, dBm into
600 Ω (or other resistance values),
or watts for AC level measurements,
and select percent or dB for distortion
measurements.
Amplifier testing
Generator output
Figure 8. Audio testing using the U8903A
Swept measurements
With its internal audio source and
precise digital control, the U8903A
can perform automatic swept measurements of frequency response,
distortion, and signal-to-noise. For
example, to check the frequency
response of an active filter, only a few
steps are required. After connecting
the device and setting the required
source level, simply enter the start
and stop frequencies, and then press
the “Sweep” key (Figure 9).
Analyzer
input
Audio amplifier
Standard and custom filters
A selection of built-in filters simplifies
audio measurements by providing
weighting networks required by international standards. These include
CCIR, CCIR/ARM, and CCIT weighting
filters; a C message filter; and an
ANSI “A” weighting filter. In addition
to the standard filters, you can create
custom filters using applications
such as MATLAB or Agilent VEE
and upload the filters through the
Figure 9. Use a single button to access the swept measurement mode
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