The Optimal Solution to Ensure the Excellent

The Optimal Solution to Ensure the Excellent
The optimal solution to ensure the excellent
certification quality of EMI testing
1
The Optimal Solution to Ensure the Excellent
Certification Quality of EMI Testing
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The optimal solution to ensure the excellent
certification quality of EMI testing
2
3GHz Spectrum Analyzers have become an important
With the advancement of high-tech development, the
tool to characterize the EMI testing
issues of EMI come out and diffuse over the broad
In terms of propagating path, there classify into
electronic applications. The increasing operating speed
conducted EMI and radiated EMI. The conducted EMI
and integrated density semiconductor devices are
results from that the radiated signal adheres along the
enlarging the higher noise level than before so that many
power line and hard to detect and recognize. Therefore, it
of the distortion sources of signal become hard to detect
is necessary to build the causes and effects methodology
and recognize. Therefore, it is necessary to build the
by way of the correct measurement to maintain the
causes and effects methodology by way of the correct
electromagnetic compatibility, to target the
measurement to maintain the electromagnetic
electromagnetic interference, and to detect radio
compatibility, to target the electromagnetic interference,
frequency interference. With the state-of-art design
and to detect radio frequency interference.
among various testing devices, outstanding low noise
floor level of -117dBm at 1 GHz of the 3GHz spectrum
With the state-of-art design among various testing
analyzer performs extreme sensitivity for picking up weak
devices, outstanding low noise floor level of -117dBm at 1
signals.
GHz of the 3GHz spectrum analyzer performs extreme
sensitivity for picking up weak signals. Along with a
20dB-gain preamplifier, the 3GHz spectrum analyzer can
further reach an equivalent noise floor level as low as
-137dBm, widely extending the measurement range. The
transient signal optimization on this spectrum analyzer
enables measurement of the power in rapid grasping the
EMI sources. These capabilities make the 3GHz spectrum
analyzer uniquely suited to solving today’s EMI problems.
The requirements of Electromagnetic compliance testing
Fig. 1. Using GKT-006 Probes for EMI Emission
has become the key indicator to forecast the market
Diagnosis Systems that have been well adopted for
potential for 3GHz Spectrum Analyzer
EMC/EMI pre-test of electronic product before delivering
Electromagnetic compliance (EMC) remains a hot topic
to EMI certification Lab, for example.
among regulatory groups and manufacturers. With the
continued integration of electronics in consumer devices,
Along with a transports along other electronic devices or
there will be a significant increase in the number of
component. And the radiated EMI caused by the
possible electromagnetic sources present in any given
unwanted signal of harmonics generated from the system
environment. EMC testing, therefore, is necessary to
case, antenna or electronic component transmits as a
guarantee the safe and effective operation of such
electromagnetic wave to distort other electronic systems.
products. To combat the risks associated with
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The optimal solution to ensure the excellent
certification quality of EMI testing
3
electromagnetic interference (EMI), product
With their small footprints and portable nature, such
manufacturers are adopting spectrum analyzers as
products allow for utility both in the field and on the
reliable tools for EMC testing. Typically lightweight and
bench. Despite the increased use of handheld devices,
feature-rich, spectrum analyzers can be used in
spectrum-analyzer vendors must realize that their
conjunction with antennas, line impedance stabilization
revenues may be hindered by the availability of previously
networks (LISNs), and near-field probes to find EMI
used systems currently in the market, which are prime
radiation sources. The use of spectrum analyzers often
options for R&D engineers who wish to minimize
saves time and money for engineers who do not wish to
operating costs. Even with used systems available, the
travel to an EMC lab for their compliance tests. Spectrum
mature spectrum analyzer market will continue to
analyzers that can handle an 3~20GHz frequency range
experience modest growth, given its importance in EMC
are well suited for examining satellite communications
testing. There depicts market revenues from 2003 to 2007
systems’ operations, testing communications equipment,
and expected revenues for 2008 in Fig.2. With a high
and fulfilling wireless system commissioning and
degree of market competition and price sensitivity,
troubleshooting. The communications industry is
vendors must understand the importance of developing
perhaps the most important area of growth for spectrum
products with enough features and capabilities to satisfy
analyzers, as this sector continues to witness the
the testing needs of end users.
deployment of new wireless networks and standards that
must be tested for EMI. As technologies such as WiMAX,
EMI Measurement Overview
3G wireless, and WCDMA continue to evolve, they are
With a compact spectrum analyzer, the manufacturers
expected to contribute a significant proportion of
making electronic products can easily build up the
revenues to the overall spectrum-analyzer market.
production line for EMI testing or electronic system
Although spectrum analyzers have been known for their
designer can have the technical capability to develop the
somewhat hefty price tag in the past, the introduction of
high the capacity have been adopted by way of radiated
lower- cost testers has made such devices more
EMI ad Conducted EMI. For a formal EMI certification
affordable and desirable to many end users. This is
test, in either an EMI chamber or an open field site, the
largely attributed to vendors who have moved toward the
receiving antenna will pick up the emissions with in a
development of less-expensive handheld devices.
distance of 8 or 10 meters. This means the emissions may
come from anywhere within the DUT. The antenna will
receive them all the emissions, they can come from the
top, bottom, right or left hand side.
Fig. 2. There is a wide range of human risk associated
with electromagnetic interference
Fig. 3. EMI testing in Open side.
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The optimal solution to ensure the excellent
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In Fig.3, the DUT is placed on a rotatable table, the
with plastic so that short circuits to the DUT are avoided.
receiving antenna is located 10 meters from the DUT, and
Different types of probes are chosen to fit different
its stature is adjustable. The antenna output is connected
frequencies and DUT shapes. The tip probe is a direct
to a spectrum analyzer which is located in a shielded
touch probe which allows the probe tip to directly test the
room. A perfect Ground is needed to ensure an isolated
circuits. Even though there is no ground connection to
environment. During the measurement, the table will
the probe the FR signal can still be measured for spot
rotate 360 degrees, so that the antenna can receive the
testing and location measuring.
omni directional emissions. The antenna is also vertically
adjustable to catch the upward emissions. However, the
A Spectrum analyzer is the most widely used instrument
EMI testing results can not distinguish where on the DUT
for EMI emission measurements. A spectrum analyzer
the emissions were generated. When the emissions are
provides the frequency and strength information of
too strong and fail to pass regulations, the source needs
signals. With the use of a moving probe the source
to be suppressed and thus have to be identified first. The
location of emissions can be found rapidly. For diagnostic
near field probe is used to find the source of emissions on
purposes, it is recommended that our spectrum analyzer
the DUT.
is used in the “Peak Hold” trace mode to record
emissions. If emissions are weak, an additional
preamplifier can be used for amplifying emissions for
measurement. Besides, the 3GHz spectrum analyzer can
be an automatic test instrument instead of external
computer control. Users can define their own macros
through keypad on the front panel and store them into
sequence sets at most. Each sequence including pause
Fig. 4. Moving the probe around the DUT
steps, which can be paused at the instant while observing
the measurement result. The quick EMI pretest can be
The GKT-006 is a near field probe set which is used to
implemented on spectrum analyzer with EMI filter.
connect to a spectrum analyzer (in most of cases) to
detect the E or H field. The detection is done by holding
the probe and moving it around the DUT as shown in
Fig.4. When the probe is moved to the vicinity of the
source, the E/H field will be inducted through the probe,
showing the measured strength on the spectrum
analyzer. The emission source can be located accordingly.
During the operation, the probes (two loop and one stub
probe) are used by means of “non-direct touch” so the
probes will induct the E/H field. The probes are insulated
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Fig. 5. The typical 3GHz Spectrum Analyzer
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The optimal solution to ensure the excellent
certification quality of EMI testing
5
the configuration as shown in Fig.9. This connection is
well performed on spectrum analyzer instead of the
oscilloscope that can’t activate the RF detection kit
without 50Ω input impedance.
Fig. 6. The main tool of EMI diagnostic package
Fig. 8. BNC probe Connections is well-posed with RF
cable and loop probes ANT-01, ANT-02 and ANT-03,
which enable to measure the background noise of
peripheral signal from TV or radio.
Fig. 7. The EMI-specific software installed in EMI
diagnostic package
Interfaces and Connections of EMI Measurement
The probes have different connector types due to their
characteristics. When a probe is connected to a spectrum
analyzer, a suitable adapter is needed. Possible
connections are as follows.
1.
When the loop probes ANT-01, ANT-02 and ANT-03
are connected to a spectrum analyzer, an N to BNC
adapter (ADP-01) is needed because these probes
Fig. 9. Correct connections is well-posed with SMA cable
are BNC type connectors. The cable used in the
and probe detector PR-03 to track the circuit conduction
GKT-006 is a test lead with BNC connectors at both
2.
ends.
In terms of a spectrum analyzer set-up, we shall have the
One can use probe detector PR-03 to point out and
primary setting of frequency range by scanning two zones,
track the conduction properties of electrical circuit by
30MHz~300MHz and 300MHz~1GHz under 120KHz of
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The optimal solution to ensure the excellent
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RBW setting. At first, enter the function key ”Trace” and
To attain the highly precision in robot movement along
select “Peak” to pick out the main sources of largest
the process chambers on equipment is significantly
noise level by sequence as “Trace” then “More” then
affected by the normal programmable operation. And the
“Detection”. In terms of the further advanced test, we
preventive maintenances of the equipment often spent
can choose the major source of noise peak120MHz, for
much time and efforts while going for the preliminary
example. Assign the center frequency as this noise
check with conducted EMI calibration as shown in
peak120MHz and set the frequency span to 4MHz. Then
Fig.11.[1]
select “Detection”, then enter ”Q Peak”, and use “AVG”
to pick out the maximum and average value which will be
the practical way.
Example 1. Quickly checking the conduction properties of
electrical circuit
Fig. 11. It takes much time for certification connection for
normal conducted EMI, which can cost-efficiently adopt
the pre-test measurement by simple EMI emission
detection.
The profound influence Pre-test by Spectrum analyzer
Measurement System on Conducted EMI certification
Fig. 10. Optimal solution of EMI emission Measurement
The noise sources can be decomposed into common
mode noise and differential mode noise. These two
As shown in Fig.10, applying kits of loop probes to
components of noise sources are respectively caused by
proceed in simple tracking the EMI characteristics will
their associated current. The noise can be extracted from
make it possible to save much more time in testing site
the line impedance stabilization network (LISN), shown in
of production line. There are kits including ANT-01, BNC
Fig.12, the measured value after feed through noise
cable, ADP-01 and a 10dB pre-amplifier GAP-802 to
separator can be acquired by spectrum analyzer. With a
capture the EMI emission source in this figure.
EMI detection bundled on a 3GHz spectrum analyzer,
Either involving the commitments of EMI detection or
Example 2. The Pre-test Measurement for the Advanced
simply build the easy connection may allow you to get rid
Test on the Process Equipments in Semiconductor
of most of the EMI troublesome.
Manufacturing Sector
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The optimal solution to ensure the excellent
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by rapidly identifying the issues. This can prevent the
lengthy setbacks that can occur with outdated and
inefficient test equipment.
DUT
References
[1] A, Krusubthaworn, R. Sivaratana, V. Ungvichian, A.
Siritaratiwat., Testing parameters of TMR heads affected
by dynamic-tester induced EMI, Journal of Magnetism
Spectrum Analyzer
and Magnetic Materials 316(2007) e142-e144.
Fig. 12. Measurement system for Conducted EMI.
As an approach to killer application, 3GHz spectrum
analyzer inherits the advantages if high performance,
affordable cost, easy to use and light-weight portability.
Moreover, its extremely low noise floor greatly increases
the measurement range, advanced user interface brings
users with significant visual enhancement, and versatile
powerful functions make measurements simple and
accurate. The 3GHz spectrum analyzers have been offers
with the greatest performance-to-price ratio in the
market. Using the 3GHz spectrum analyzer as a
EMI/EMC pre-test measurement tool will likely eliminate
the possibility of measurement algorithm errors after
addressing the EMI testing in certification lab. The
leadership of 3GHz spectrum analyzer in delivering the
test industry’s first dedicated EMI measurement suite has
given it rapid adoption by a wide range of EMI/EMC
certification. There is a very good chance that one’s
electronic product will successfully undergo EMI/EMC
certification test with the 3GHz spectrum analyzer
making many of the measurements. If an issue does arise
during the EMI/EMC test, having the easily
portable single box SA available provides a means to
quickly troubleshoot circuits. The 3GHz spectrum
analyzer can help the engineer rescue the EMI/EMC effort
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GOOD WILL INSTRUMENT CO., LTD.
The optimal solution to ensure the excellent
certification quality of EMI testing
8
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