1. What can CISPR do to help ?
Martin Wright

2. 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

3. 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
Picked up in Europe through parallel voting in CENELEC

5. 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

6. 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

7. 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

8. So what can CISPR do to help?
1 we can ask CISPR via liaison statements to check limits using CISPR 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.

9. 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)

10. Any Questions ?
Thanks for listening….