CISPR 22, Amendment 1 Ferrite Clamps
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® 04/29/2002 CISPR 22, Amendment 1 Ferrite Clamps Ghery S. Pettit, NCE Intel Corporation Corporate Product Regulations
description
CISPR 22, Amendment 1 Ferrite Clamps. Corporate Product Regulations. Ghery S. Pettit, NCE Intel Corporation. Topics. OATS Qualification Amendment 1, CISPR 22:1997 Problems. Typical OATS Facility. OATS Qualification. Normalized Site Attenuation Transmit antenna on turntable center - PowerPoint PPT Presentation
Transcript of CISPR 22, Amendment 1 Ferrite Clamps
®04/29/2002
CISPR 22, Amendment 1Ferrite Clamps
Ghery S. Pettit, NCEIntel Corporation
Co
rpor
ate
Pro
duc
t Reg
ula
tion
s
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Topics
• OATS Qualification• Amendment 1, CISPR 22:1997• Problems
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Typical OATS Facility
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OATS Qualification
• Normalized Site Attenuation– Transmit antenna on turntable center– Receiver antenna on tower– +/- 4 dB and you pass
• Nothing said about– Power distribution to EUT– Cables to remotely located peripheral devices
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Long Wire End Fed Antennas
• Random length wire• Transmitter at one end• Far end – who knows where?
xmtr
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Look Familiar?
• EUT = Transmitter• Power cord = Antenna• Power feed (from who knows where?) =
End support and termination
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Common Unknowns
• Wire length (resonant frequencies)• Wire termination (load)• Wire orientation (once it leaves the
turntable)
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How To Standardize?
• Standard wire length and layout– Redesign labs?
• Major world-wide expense• Not likely to be accepted
– LISNs at power plugs?• What about labs where power is under the table?• What about labs where there isn’t room?
• Solution is to decouple all but the cable in the test area.
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CISPR 22, 3rd Edition, Amendment 1(EN 55022:1998, Amendment 1)
• Adds ferrite clamps – all cables leaving the measurement area for
table top EUTs – at the surface of the turntable– 1 cable per clamp
• Published in August 2000.• Has been adopted by Israel and the EU.• Required in EU by 1 August 2003.
– Israel now, others later
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Ferrite Clamps
Table top products only
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Ferrite Clamp Definition
• The clamp shall– Provide at least 15 dB of loss in a 50 ohm system– 30 MHz to 1000 MHz
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Does It Work?
• Tests performed by Intel and Hewlett Packard in early 2000 to aid in the US vote on the amendment
• Comb generator to power cord via a CDN• Radiated emissions measured every 5 MHz from
30 MHz to 200 MHz• 4 lab configurations with a single clamp
– Schaffner INA 726 Isolation Clamp
• 2 lab configurations with 3 different clamps– Schaffner INA 726 Isolation Clamp– MDS 21 Absorbing Clamp– Fischer Custom Communications F-203I-23mm EM
Clamp
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Test Setup – No Ferrite Clamp
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Test Setup – With Ferrite Clamp
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4 Sites – No Ferrite
Measured Signals - No Ferrite
15
20
25
30
35
40
45
50
30 40 50 60 70 80 90 100
110
120
130
140
150
160
170
180
190
200
Frequency (MHz)
Sig
nal
(d
Bu
V/m
)
HP - NEMA Outlet HP - LISN Outlet Intel DuPont Intel Oregon
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4 Sites – With Ferrite
Measured Signals - Ferrite on Cord
15
20
25
30
35
40
45
30 40 50 60 70 80 90 100
110
120
130
140
150
160
170
180
190
200
Frequency (MHz)
Sig
nal
(d
Bu
V/m
)
HP - NEMA Outlet HP - LISN Outlet Intel DuPont Intel Oregon
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4 Sites - Summary
Effect of Adding Ferrite Clamp
0
5
10
15
20
2530 40 50 60 70 80 90 10
0
110
120
130
140
150
160
170
180
190
200
Frequency (MHz)
Sp
read
(d
B)
Data Spread - No Ferrite Clamp Data Spread - Ferrite Clamp
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3 Clamps – Two Power Feeds
Clamp Comparison
20
25
30
35
40
45
30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Frequency (MHz)
Sig
nal
Lev
el (
dB
uV
/m)
NEMA Outlet - Schaffner INA 726 NEMA Outlet - MDS 21
NEMA Outlet - FCC Clamp LISN - Schaffner INA 726
LISN - MDS 21 LISN - FCC Clamp
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Two Power Feeds – No Clamp
HP Chamber Results - No Ferrite
15
20
25
30
35
40
45
30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Frequency (MHz)
Sig
nal
Lev
el
(dB
uV
/m)
NEMA Outlet LISN Outlet
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Two Power Feeds – INA 726
Schaffner INA 726
20
25
30
35
40
45
30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Frequency (MHz)
Sig
nal
Lev
el
(dB
uV
/m)
NEMA Outlet LISN Outlet
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Two Power Feeds – MDS 21
MDS 21
20
25
30
35
40
45
30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Frequency (MHz)
Sig
nal
Lev
el
(dB
uV
/m)
NEMA Outlet LISN Outlet
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Two Power Feeds – FCC EM Clamp
Fischer Custom Communications Clamp
20
25
30
35
40
45
30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200
Frequency (MHz)
Sig
nal
Lev
el
(dB
uV
/m)
NEMA Outlet LISN Outlet
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Initial Conclusion
• Clamps improve repeatability between labs• Clamps improve repeatability between different
types of power feeds in the same lab• Different clamps converge to different solutions
– Why?
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One More Clamp Characteristic
• Need to specify the input impedance for a wire passing through the clamp
• Measurements show each clamp utilized– Meets the 15 dB loss requirement from 30 MHz to 1000
MHz– Has a different impedance characteristic
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INA 726 Input Impedance
Schaffner INA 726 Input Impedance
0
100
200
300
400
500
600
700
800
900
1000
0 100 200 300 400 500 600 700 800 900 1000
Frequency (MHz)
Ohm
s
Open Shorted
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MDS 21 Input Impedance
MDS 21 Input Impedance
0
200
400
600
800
1000
1200
1400
1600
1800
2000
0 100 200 300 400 500 600 700 800 900 1000
Frequency (MHz)
Ohm
s
Open Shorted
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FCC EM Clamp Input Impedance
Fischer F-203I-23mm Clamp Input Impedance
0100
200300
400500600
700800
9001000
0 100 200 300 400 500 600 700 800 900 1000
Frequency (MHz)
Ohm
s
Open Shorted
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Where Do We Go From Here?
• Problem #1– CISPR 22 uses ferrite clamps on cables– ANSI C63.4 does not
• Problem #2– CISPR 22 does not adequately define the clamps– What should the input impedance to the wire through the
clamp be?
