CISPR 22, Amendment 1 Ferrite Clamps

1. CISPR 22, Amendment 1Ferrite Clamps Corporate Product Regulations Ghery S. Pettit, NCE Intel Corporation

2. Topics • OATS Qualification • Amendment 1, CISPR 22:1997 • Problems

3. Typical OATS Facility

4. 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

5. Long Wire End Fed Antennas • Random length wire • Transmitter at one end • Far end – who knows where? xmtr

6. Look Familiar? • EUT = Transmitter • Power cord = Antenna • Power feed (from who knows where?) = End support and termination

7. Common Unknowns • Wire length (resonant frequencies) • Wire termination (load) • Wire orientation (once it leaves the turntable)

8. 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.

9. 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

10. Ferrite Clamps Table top products only

11. Ferrite Clamp Definition • The clamp shall • Provide at least 15 dB of loss in a 50 ohm system • 30 MHz to 1000 MHz

12. 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

13. Test Setup – No Ferrite Clamp

14. Test Setup – With Ferrite Clamp

15. 4 Sites – No Ferrite

16. 4 Sites – With Ferrite

17. 4 Sites - Summary

18. 3 Clamps – Two Power Feeds

19. Two Power Feeds – No Clamp

20. Two Power Feeds – INA 726

21. Two Power Feeds – MDS 21

22. Two Power Feeds – FCC EM Clamp

23. 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?

24. 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

25. INA 726 Input Impedance

26. MDS 21 Input Impedance

27. FCC EM Clamp Input Impedance

28. 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?