Transcript landscape Powerpoint Template

Overview of Radiated Immunity Testing in a
Reverberation Chamber
Presented by
Craig Fanning
Elite Electronic Engineering Inc.
2006 Automotive EMC Standards Workshop
January 30 & 31, 2006
Dearborn, Michigan USA
1
Overview
 Scope
 Several SAE Standards cover Reverberation Chamber
Radiated Immunity testing on Vehicles and Components
 J551-16: Vehicle Level Reverberation Radiated Immunity
(Mode Tuned and Mode Stirred Methods Covered)
 J1113-27: Component Level Reverberation Radiated
Immunity (Mode Stir Method Covered)
 J1113-28: Component Level Reverberation Radiated
Immunity (Mode Tuned Method Covered)
 These are alternative methods to testing in an Absorber
Lined Shielded Enclosure (ALSE) as described in J551-11
and J1113-21.
 In all of the above standards, the electromagnetic
disturbance is limited to continuous narrow band
electromagnetic fields.
2
Overview
 Corresponding International Standards:
 J551-16: Currently there is no ISO standard for reverberation
chamber radiated immunity at the vehicle level. Portions of
IEC 61000-4-21 and IEC 61000-4-3 were used for
development of this standard.
 SAE J1113-27: Currently there is no ISO standard for Mode
Stir reverberation chamber radiated immunity on automotive
components. Mode Stir radiated immunity testing is
discussed in IEC 61000-4-21, however, the main focus of
IEC 61000-4-21 is Mode Tuned techniques.
 SAE J1113-28: Currently there is currently no ISO standard
for Mode Tuned reverberation chamber radiated immunity on
automotive components. Mode Tuned radiated immunity
testing is covered in IEC 61000-4-21 and is the basis of the
J1113-28 document.
3
Overview
 Terms and Definitions:
 Reverberation Chamber: A high Q shielded room whose
boundary conditions are changed via a rotating tuner. This
results in a time-averaged uniform electric field.
 Chamber Quality Factor (Q): Q factor is the measure of a
chambers ability to reverberate. The Q factor is effected by
the chamber dimensions and wall material.
 Tuner: A rotating metallic reflector that changes the boundary
conditions in a reverberation chamber as it rotates. As the
tuner rotates the nulls and maximums of the field change
location. This ensures that the DUT and wiring harness are
exposed to a time-averaged uniform field.
4
Typical Reverberation Chamber
5
Chamber Design
 When selecting a mode tuned chamber, the desired usable
frequency range and internal working volume needs to be
considered. This will dictate the chamber size.
 For optimum chamber performance, especially at low
frequencies, the volume of the chamber should be as large as
possible and the room dimensions should not be integer
multiples of one another. Rooms with integer multiple
dimensions will have degenerative modes (room may not
reverberate at all frequencies).
 Minimum recommended room dimensions are 4.88m x 3.66m
x3.05m (16ft L x 12ft W x 10ft H)
 The chamber size and tuner size will effect the lowest usable
frequency (frequency cutoff) of the chamber.
6
Tuner Designs
 The criteria for tuner design is to ensure its effectiveness in
redistributing the energy inside the chamber.
 The tuner should be electrically large (greater than or equal to
the wavelength at the lowest frequency of operation).
 It shall be shaped and oriented to achieve a receive power
maximum/minimum ratio of greater than or equal to 20dB. As
the tuner rotates, the difference of the Emax and Emin RF
fields, measured at a fixed location, shall change by 20dB or
greater.
 The is tuner is operated in step/stop/step/stop type of operation
during Mode Tuned testing.
 The tuner is continuously rotated during Mode Stir testing.
7
Tuner Designs: Foam Board Tuner
8
Tuner Designs: Z-Fold Design
9
Tuner Designs: MIL-STD-1344A
10
Mode Tuned vs Mode Stir Testing
 Mode Tuned Reverberation:
 The tuner needs to be driven via a computer controlled
stepper motor in order to achieve a step/stop/step/stop type
of operation. Computer will also control RF Generation and
RF Monitoring equipment.
 The field generating antenna is pointed into the corner of the
chamber to eliminate direct coupling to the DUT.
 A constant field can be applied to the DUT for a specified
dwell time at each tuner stop point.
 The number of tuner steps is dependent upon the chamber
calibration data (minimum 12 steps is suggested)
 Multiple runs with different antenna polarities and DUT
orientations are not required. This is due to the loss of field
polarity and the DUT is immersed in the applied field.
 This method requires chamber characterization per IEC
61000-4-21 and SAE J1113-28, with and without the DUT.
11
Mode Tuned vs Mode Stirred Testing
 Mode Stir Reverberation:
 The tuner can be rotated continuously with a gear reduction
AC motor.
 The RPM of the tuner should be adjustable for units with
different response times (typically 10-20seconds/revolution).
 The field generating antenna is typically pointed into the
corner of the chamber to eliminate direct coupling to the
DUT. This method requires chamber characterization per
SAE J1113-27, with and without the DUT.
 The dwell at each frequency and modulation tested is
typically the time it takes for one full rotation of the tuner.
 Multiple runs with different antenna polarities and DUT
orientations are not required since the since there is loss of
field polarity and the DUT is immersed in the applied field.
12
SAE J551 Part 16
Electromagnetic Immunity – Off-Vehicle Source
(Reverberation Chamber Method)-Part 16- Immunity to
Radiated Electromagnetic Fields
Presented by
Craig Fanning
Elite Electronic Engineering Inc.
2006 Automotive EMC Standards Workshop
January 30 & 31, 2006
Dearborn, Michigan USA
13
Overview
 SAE J551-16 specifies Radiated Immunity (Reverberation
Chamber) test methods and procedures for the testing of
passenger cars and commercial vehicles. J551-16 provides a
means of coupling RF energy to the electrical system of
vehicles. It is an alternative to testing in an Absorber Lined
Shielded Enclosure (ALSE) radiated immunity test as described
in J551-11.
 Three methods of reverberation radiated immunity testing are
covered in the standard:
 Mode Tuned
 Mode Stir (Standard)
 Mode Stir (Hybrid)
14
Revision of Standard
 SAE J551-16 is a new standard developed by the SAE
Standards Committee. The original publication date was
September 2005.
 The specification is a culmination of test methods currently
being used by Vehicle OEMS and Independent Test
Laboratories to evaluate vehicle performance when
exposed to Radiated RF Fields.
 The specification is currently a Surface Vehicle
Recommended Practice. After a few years of use and
during it’s next revision…the specification will most likely
become a Surface Vehicle Standard.
15
International Standards
 Corresponding International Standards: Currently there is no
ISO standard for reverberation chamber radiated immunity
testing at the vehicle level.
 The Mode Tuned test methods are a variation of the
component test specification SAE J1113-28.
 The Mode Stir (Standard) test methods are a variation of the
component test specification SAE J1113-27.
 The Mode Stir (Hybrid) test methods are unique and field
uniformity measurements similar to IEC 61000-4-3 are used
for chamber performance verification.
 If International Compliance is of concern…a test in an ALSE
chamber would currently be required to meet 95/54/EC or
2004/104/EC.
16
Test Configurations - Typical
17
Test Configurations - Typical
 The Mode Tuned and Mode Stir (Standard) test methods (Figure 1)
are well suited for the evaluation of smaller vehicles such as
Motorcycles, Passenger Cars and Pickup Trucks. Chambers needed
for the testing of large vehicles may be too lossy for these methods.
 Illumination of the entire vehicle is possible without the need of
multiple antenna polarizations and antenna positions about the
vehicle.
 Since the RF field is bombarding the vehicle from many different
directions, better coverage of the vehicle is achieved. This reduces
the chance of missing a potential issue that may not be found in the
ALSE chamber.
 Large vehicles may cause chamber loading issues which may not
allow the use of these indirect “shoot-in- the-corner” illumination
methods.
 The Mode Tuned method requires extensive chamber
characterization per SAE J1113-28 and IEC 61000-4-21.
 The Mode Stir (standard) test method requires chamber
characterization per SAE J1113-27.
18
Test Configurations - Hybrid
19
Test Configurations - Hybrid
 The Mode Stir (Hybrid) test method (Figure 2) was developed
for the testing of large vehicles such as Class 8 Trucks, Truck &
Trailer combinations, Busses, Earth Moving Equipment and
Agricultural Equipment.
 Illumination of large areas of the vehicle is possible depending
upon the field uniformity data. Multiple antenna polarizations
and antenna positions about the vehicle will usually still be
required.
 Since the RF field is bombarding the vehicle from many different
directions, better coverage of the vehicle is achieved. This
reduces the chance of missing a potential issue that may not be
found in an ALSE chamber.
 The dwell time at each frequency is the time it takes for the
slowest tuner to make one full rotation (typically 10-20
seconds).
20
Additional Information
 During Mode Stir (Alternate) and Mode Stir (Hybrid) tests, the
field intensity generated is typically measured with a receive
antenna in conjunction with a spectrum analyzer. The fast
sweep speed of a spectrum analyzer will allow the maximum
field to be measured. The use of an isotropic probe is allowed
only if the isotropic probe has a high sampling rate (50Hz
suggested). A high sampling rate isotropic probe will allow the
peak maximum RF field to be measured. If the sampling rate of
the isotropic probe is not fast enough, the peak field actually
being generated may be much higher that what is being
displayed.
21
Future Trends
 SAE EMC standard revisions are typically on a 5 year rotation.
 J551-16 was published in September 2005
 Next revision of this standard will begin again in the 2009/2010
timeframe.
 A major change of referenced SAE standards, international
standards or input of the users may justify an earlier revision.
 Possible Changes:
 Become a Surface Vehicle Standard?
 Questions? Comments? Changes requested by Audience?
22
SAE J1113 Part 27
Electromagnetic Compatibility Measurements Procedure
for Vehicle Components – Part 27
Immunity To Radiated Electromagnetic Fields – Mode
Stir Reverberation Chamber Method
Presented by
Craig Fanning
Elite Electronic Engineering Inc.
2006 Automotive EMC Standards Workshop
January 30 & 31, 2006
Dearborn, Michigan USA
23
Overview
 SAE J1113-27 specifies Radiated Immunity (Reverberation
Chamber) test methods and procedures for the testing of
components before they are installed in the vehicle. It is an
alternative to testing in an Absorber Lined Shielded Enclosure
(ALSE) radiated immunity test as described in J1113-21.
 The J1113-27 specification covers the “Mode Stir” radiated
immunity test technique.
 The specification continues to be a Surface Vehicle
Recommended Practice.
 Corresponding International Standards: Currently there is no
ISO standard for radiated immunity testing of vehicle
components in a reverberation chamber. IEC 61000-4-21 was
used for the basis of some of the methods described in the
document.
24
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
Revision OF Standard
The original publication of SAE J1113-27 was February 1995.
The original specification was a clone of GM 9120P.
Galen Koepke of NIST began work on the next revision of the
standard in 1999. Improved procedures and formulas for the
measurement of chamber performance and calculation of field
generated were developed. Work on the document was halted
in 2001 since the industry was leaning towards Mode Tuning
and IEC 61000-4-21 was in development. At the time, J1113-27
would become a Mode Tuned test method.
In 2004, a decision was made by the SAE committee to
continue work on J1113-27 as a Mode Stir document. A new
document (SAE J1113-28) would be developed for Mode Tuned
testing based upon recently published IEC 61000-4-21.
J1113-27 was then completed and published in September
2005. The revised document included much of the technical
work done by Galen Koepke in 1999-2001.
25
Test Configurations
26
Test Configurations
27
Major Changes (from the previous version)
 There were many changes to the original document during the
revision process. The major technical changes during this
presentation.
 Major Changes:
 Section 3 “Definitions”:
 “K Factor” (Paragraph 3.9 of original document) – This
factor is no longer used nor referenced in the revised
document.
 “Stirrer” is now referred to as a “Tuner” in Para 3.2. The
term “Tuner” is consistent with recent terms and
definitions.
 Definition for Chamber Quality Factor (Q) was expanded
in Para 3.4 of revised document .
28
Major Changes (from the previous version)
 Major Changes (cont):
 “Test Conditions” was added to the document as Section 5.
 This section includes:
 5.1 Test Temperature and Supply Voltage
 5.2 Frequency Range
 5.3 Modulation (CW, AM and Pulse)
 5.4 Dwell Time (One Tuner Rotation)
 5.5 Frequency Steps (Linear and Logarithmic)
 5.6 Test Signal Quality
 5.7 Threshold of Response
 5.8 Test Severity Levels (Peak Power Conservation)
29
Major Changes (from the previous version)
 Major Changes (cont):
 “Test Setup” now Section 6.0 of revised document
 Harness length is now defined as 1.7m to 2m (previously
1m to 3m)
 Setup drawings updated and improved.
 “Test Procedure” now Section 7.0 of revised document. This
section was completely rewritten to include:
 “Preliminary System Check” Para 7.3
 “Chamber Field Calibration” Para 7.4
 “DUT Test” Para 7.5
30
Major Changes (from the previous version)
 Major Changes (cont):
 “Test Report” now Section 8 of revised document
 Para 8.13 added “The (tuner) rotation rate at each
frequency, as well as the method used to determine the
rotation rate, must be documented in the report.”
 Appendix A most of this appendix is unchanged. Points of
interest:
 A.1.4 “Tuner Design”: The foam board tuner shown in the
original document was a tuner developed by GM. The
foam board tuner remains in the revised document. A
modern “Z-Fold” tuner, that is used in commercially
available chambers, is also described in the revised
document.
 A.1.2 “Chamber Quality Factor (Q)”: formulas and A.4
“Electric Field Uniformity” formulas: Unchanged
31
Major Changes (from the previous version)
 Major Changes (cont):
 Appendix B:
 B.1 through B.7 basically the same.
 The minimum loss of the unloaded chamber is calculated in
B.8 of the revised document (Previously done in B.12).
Calculation similar.
 “K Factor” calculation (Step B.11 of original document) has
been removed. “K Factor” is no longer used.
 The equivalent field strength is calculated in B.9 of the
revised document (Previously done in B.8). The formula for
this calculation has been changed.
 B10 through B13 of revised document (Previously B13-B16)
are basically the same as original document.
 “K Factor” no longer referenced in Table B1 of revised
document.
32
Major Changes (from the previous version)
 Major Changes (cont):
 Appendix C:
 “Test Severity Levels” updated in accordance with SAE
J1113-1 and SAE J1812.
 Table C2 also shows suggested test severity levels,
performance criteria, and pulse modulations for Pulse
Modulated testing.
33
Future Trends
 SAE EMC standard revisions are typically on a 5 year rotation.
 J1113-27 was revised and published in September 2005.
 Next revision of this standard will begin again in 2009/2010
timeframe.
 A major change of international standards may justify an earlier
revision.
 Possible Changes:
 Become a Surface Vehicle Standard?
 Currently do not see any other changes. As committee
receives input, changes will be considered for next revision.
 Questions? Comments? Changes requested by Audience?
34
SAE J1113 Part 28
Electromagnetic Compatibility Measurements Procedure
for Vehicle Components – Part 28
Immunity To Radiated Electromagnetic Fields –
Reverberation Method (Mode Tuning)
Presented by
Craig Fanning
Elite Electronic Engineering Inc.
2006 Automotive EMC Standards Workshop
January 30 & 31, 2006
Dearborn, Michigan USA
35
Overview
 Scope
SAE J1113-28 specifies Radiated Immunity (Reverberation
Chamber) test methods and procedures for testing of
components before they are installed in the vehicle. It is an
alternative to testing in an Absorber Lined Shielded Enclosure
(ALSE) radiated immunity test as described in J1113-21.
 The J1113-28 specification covers the “Mode Tuned” radiated
immunity test techniques.
 Corresponding International Standards: Currently there is no
ISO standard for radiated immunity testing of vehicle
components in a reverberation chamber. Chamber
Characterization and Test methods described in the document
adopted methods of IEC 61000-4-21.
36
Revision of Standard
 SAE J1113-28 is a new standard developed by the SAE
Standards Committee. The sponsor of the document was
Ronald Webb. The original publication date was November
2004.
 The published specification is a culmination of test
methods currently being used by Vehicle OEMS and
adopts the methods of IEC 61000-4-21.
37
Test Configurations
38
Test Configurations
39
Chamber Calibration
 Chamber Design and Theory are covered in Appendix A,
Paragraphs A.1 through A.4.
 Prior to any testing, an extensive characterization of the
chamber must be performed per Appendix A and Appendix B.
Calibration Procedure is discussed in Paragraph A.5. Chamber
Calibration procedures are in Appendix B and C.
 The chamber characterization is only performed once in the
lifetime of the chamber, as long as no internal changes are
made to the chamber. If internal changes are made to the
chamber then the characterization must be redone.
 A chamber working volume must be established as described in
Para A.5.1 and as determined by Para B.1.1.
40
Chamber Calibration
41
Chamber Calibration
 The calibration procedure collects Isotropic E-field probe data
(maximum data only) as well as chamber input power and the
maximum and mean received power from a reference antenna
placed within the working volume.
 The probe data is used to determine the field uniformity.
 The probe data and chamber input power is used to determine
the chamber calibration factor.
 The mean received power from the reference antenna and
chamber input power is used to determine the Antenna
Calibration Factor (ACF). The ACF is used as a reference value
when determining if the chamber has been “loaded” by a DUT.
 The maximum received power is from the reference antenna is
used to verify the probe readings.
42
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
Chamber Calibration
Probe data are collected from nine locations that form the
corners of the “volume of uniform field” or “working volume” as
shown in figure 11.
Each time the probe is moved to a new location, the reference
antenna is moved to a new location within the working volume.
The orientation of the reference antenna relative to the chamber
axis is also changed at least 20 degrees relative to each axis at
each position. This ensures that any bias in the field is detected
(e.g. no dominate polarization within the chamber).
A minimum of nine locations for both probe and reference
antenna is required.
The calibration is done in log spaced frequency steps of Table
B1 (see Para B3.3 of J1113-28).
Once a chamber has been shown to operate properly over a
frequency span of 300 to 400MHz at the minimum number of
tuner steps (i.e. 12 tuner steps), the number of locations can be
reduced to three.
43
Chamber Calibration
44
Chamber Calibration
 The uniformity of the field will depend upon the number of tuner
positions (N) used to collect the data. For a relatively modest
number of tuner steps (i.e. 12), a reasonably uniform field can
be obtained. Table A1 lists the number of tuner steps
“recommended” for performing the calibration. The number of
steps may need to be decreased or increased to optimize
performance. The minimum number of tuner steps should not
be less than twelve.
 We found that 18 tuner steps provides best results.
 Every chamber will have a low frequency cutoff in which it is no
longer “overmoded”, and hence, it can no longer be used as
reverberation chamber. The low frequency cutoff of the chamber
will mostly be dependent upon the chamber size. The
“undermoded” condition may be compensated for by increasing
the number of tuner positions but the effects may be limited.
45
Chamber Calibration
 Take the data and process it per Appendix B. There will be an
enormous amount of data. The data will need to be taken with
the same computer and software used to control the tuner, RF
generation and RF monitoring equipment. Obtaining this data
manually would probably take years.
 After processing, the chamber characterization data is then
used with the Formula for “Generating a Test Environment”
found in Appendix A, Paragraph A 5.5
 If Pulse Modulated testing is required, Appendix A, Paragraph
A.5.6 must be considered.
 An “Alternate Method for Determination of Chamber E-Field” is
discussed in Appendix C. This is applicable where the chamber
insertion loss is 10dB or greater.
 Appendix D provides suggested “Test Severity Levels”
46
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


Additional Information – Differences Between
Automotive and Other Mode Tuned Standards
The automotive standards (Ford, GM, SAE) for mode tuned
radiated immunity utilize portions of IEC 61000-4-21 and RTCA
DO-160E for chamber performance characterization and
calibration. Formulas from IEC 61000-4-21 are used in J1113-28.
The chamber performance characterization and formulas of
RTCA DO-160E (Aerospace) are slightly different than IEC
61000-4-21.
The chamber performance characterization formulas of MIL-STD461E (Military) are different from both IEC 61000-4-21 and RTCA
DO-160E.
Currently if a Mode Tuned chamber has been characterized and
the formulas of RTCA DO-160 or MIL-STD-461 were used, it
cannot be used for testing to the Automotive standards. If
sufficient data was obtained during chamber characterization, the
data can be applied to the formulas of SAE J1113-28. Otherwise
chamber re-characterization would be necessary.
47
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
Additional Information – Differences Between
Automotive and Other Mode Tuned Standards
The difference for determination of E, between the Automotive
and Aerospace standards, changes the chamber Pinput required
for the same test environment.
For the same test field intensity, approximately 3dB more power
must be delivered to the Mode Tuned chamber calibrated for
SAE J1113-28 (IEC 61000-4-21) than the chamber calibrated
for the DO-160D/E test.
Additionally, for the same test field intensity, approximately 6dB
more power must be delivered to the Mode Tuned chamber
calibrated for SAE J1113-28 (IEC 61000-4-21) than the
chamber calibrated for the MIL-STD-461E test.
How do the three methods correlate with ALSE testing?
Some studies are showing a 2dB-3dB difference between ALSE
and Automotive (IEC 61000-4-21 calibrated) Mode Tuned
chamber test results. The calculations of DO-160E may be a
better choice for improved correlation between ALSE and Mode
Tuned radiated immunity testing.
48
Additional Information – Difference Between
Automotive and Aerospace Mode Tuned Standards
 The value Etotal (mean of the normalized maximum total E-field)
in the equation shown in Para. 20.6.4.4.1 of DO-160E is based
upon the root sum square (RSS) of the magnitude of the
rectangular components at one position of the tuner.
 The value for E used in Equation B1 of SAE J1113-28 (also
Equation A.6 of IEC 61000-4-21) is the average of the maximum
E-Field measured by the probes normalized to the square root
of the input power used during the calibration. The probe
measurements used to determine the chamber E-field are the
rectangular components of the probe, not the RSS.
49
Additional Information - Calculated Field
with 1W into Chamber (DO-160 vs IEC)
MODE TUNING CHAMBER FILED UNIFORMITY VALIDATION
CHAMBER
: EMPTY
Etotal COMP. METH : RECTANGULAR COMPONENTS (Automotive)
Etotal COMP. METH : ROOT SUM SQUARE (RSS) D0-160D/E
RX ANTENNA ID : ANT38D
TX ANTENNA ID : ANT38E
NUM OF TUNER POS : 18
NUM OF PRB. POS : 9
PERFORMED ON
: 5 Jul 2005 16:47:48 P. HALL
EXCESSIVE COUNT : 5
Automotive
DO-160D/E
Freq [MHz] Et [V/m/SQRT(W)]
Et [V/m/SQRT(W)]
Difference dB
400
54.6
78.1
3.1
504.7
55.8
82.2
3.4
608
71.1
100.9
3.0
699
66.2
86.9
2.4
803.7
60.5
84.8
2.9
902.8
62.4
91.6
3.3
1000
69.8
103.8
3.4
1205
63.1
91.9
3.3
1417
59.7
88.2
3.4
1592
59.8
86.5
3.2
1789
60.8
84.0
2.8
2000
67.3
93.3
2.8
2195
75.9
107.1
3.0
2409
71.0
102.1
3.2
2583
68.4
97.8
3.1
2835
78.7
110.7
3.0
3040
77.2
113.6
3.4
3185
77.3
111.3
3.2
3415
71.0
103.5
3.3
3661
70.6
105.0
3.4
3836
76.9
107.1
2.9
50
Graphical Representation of 1W into Chamber
(DO-160 vs IEC 61000-4-21)
Normalized Electric Field V/m/Sqrt (W)
120.0
110.0
Field Intensity Level V/m
100.0
90.0
80.0
70.0
60.0
50.0
40.0
30.0
20.0
100
1000
10000
100000
Frequency MHz
 Pink – Calculated Field, DO-160 D/E Method
 Blue – Calculated Field, SAE/IEC Method
51
Additional Information – Differences Between
ALSE and Mode Tuned Testing
 During field calibration in an ALSE chamber (SAE J1113-21),
the root sum square (RSS) value of the three axis of an
isotropic probe is typically the value used for field calibration.
 As previously discussed, the RSS value of the field components
is not used for determination of E in the Automotive (IEC 610004-21) Mode Tuned chamber calibration.
 If the DO-160D/E method for calculating E (RSS value) was
used in SAE J1113-28 (also Ford and GM), better correlation
between Mode Tuned and ALSE Radiated Immunity methods
would be achieved.
 Fortunately the data obtained during a J1113-28/IEC 61000-421 chamber characterization can be reworked to determine the
RSS value of E.
52
Additional Information – Vehicle Testing Performed
to Correlate ALSE and Mode Tuned Methods
 DaimlerChrysler has both Mode Tuned and ALSE radiated
immunity capabilities at the vehicle level.
 Reverberation Test Chamber DaimlerChrysler (Chrysler Group)
53
Additional Information – Vehicle Testing Performed
to Correlate ALSE and Mode Tuned Methods
 A recent study by Andrew Shune of DCC:
 Found that thresholds obtained on a vehicle in a Mode
Tuned chamber (IEC 61000-4-21 calibrated) were
approximately 2-3dB lower than thresholds obtained on the
same vehicle in the ALSE chamber.
 It was determined that the difference in the test results
between ASLE and Mode Tuned Chambers is that; RSS
isotropic probe values are used in ALSE field calibrations
and RSS values for E are not used in the IEC 61000-4-21
chamber calibrations.
 From this information, the DCC chamber calibration approach:
 Was simplified and achieved much better uniformity.
 Demonstrated great correlation between ALSE and Mode
Tuned Chamber test results.
 Required much less Amplifier Power to achieve required field
strength.
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Future Trends
 SAE EMC standard revisions are typically on a 5 year rotation.
 J1113-28 was published in November 2004
 Next revision of this standard will begin again in the 2008/2009
timeframe.
 A major change of referenced SAE standards, international
standards or input of the users may justify an earlier revision.
 Possible Changes:
 Look further into the use of RSS values for calculation of E (per
RTCA DO-160E) to better correlate with current ALSE field
calibration practices.
 Appendix D…add suggested Pulse Modulated requirements
similar to J1113-27.
 Questions? Comments? Changes requested by Audience?
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