What can CISPR do to help ? Martin Wright

CISPR Structure CISPR is the key International committee for preparing EMC standards CISPR/A test methods and facilities CISPR/B Limits for ISM and large equipment CISPR/D Limits for Automotive CISPR/F Limits for White goods and lighting CISPR/H Interference model and limits for Generic products CISPR/I limits for Multimedia and ITE

CISPR limits Traditionally set by Ad hoc discussions CISPR aims at similar limits in similar environments Current policy is to develop new limits based on CISPR 16-4-4 Picked up in Europe through parallel voting in CENELEC

Limit Calculation 20 log 12/24 Frequency Sensitivity Protection Ratio Service tolerable Noise Bandwidth corrected tolerable Noise Time Correlation Loacation Correlation Frequency Correlation including Harmonics t_alpha* sigma P(7…9) t_beta* sigma_i Field Strength Limit MHz dBµV/m dB   Hz µ [dB] sigma [dB] dBµA/m 0,20 72 30 LF 42 9000 6 3 6,4 9,5 0,6 8 47 -5 0,28 71 41 46 -6 0,48 -1 10 Amateur Radio -11 2700 56 48 -3 1,00 60 MF 35 -17 1,91 -13 -8 36 26 -25 3,75 -16 23 -28 3,95 27 HF 20 25 -27 5,95 45 18 -29 6,10 7,15 -18 21 -30 7,25 7,33 9,45 44 17 22 9,70 10,13 -10 -20 -15 19 -32 11,63 43 16 -31 11,80 12,05 13,60 13,70 13,87 14,18 -21 -33 15,35 15 15,70 17,50 17,80 18,10 -12 -22 -34 18,95 14 21,23 -23 -35 21,65 24,94 -14 -24 -19 -36 26,00 40 13 28,80 -26 -38

In practice Key items Probability factor based on the isotropy of the source and victim Probability that emission frequency range and susceptibility frequency range overlap. Probability based that emitter and victim operate at the same time

Protection distance Protection distance draft definition is…. “The distance between the source of a radiated disturbance and the victim receiver at the edge-of-service area used for the derivation of a specific CISPR radiated disturbance limit” And the relationship between protection distance and normal use is key to achieving proper protection

So what can CISPR do to help? 1 we can ask CISPR via liaison statements to check limits using CISPR16-4-4 where we have concerns 2 We can keep providing evidence of interference cases We can highlight cases where typical use is not reflected in the protection distance etc.

And Then.. Where issues are found In an extreme case CISPR can use the standards maintenance process to update the requirements in the relevant standard Normal process applies First a Committee Draft then a voting document (takes a minimum of 1 year to change a standard) In an extreme case We can raise the issue with the EU at the EU EMC working Party The EU can request a change in the European variant of the standard (in CENELEC rather than CISPR)

Any Questions ? Thanks for listening….