Dear All, Radiated emission can be performed either on an open area test site or a semi-anechoic chamber.
Many test house do the initial scan in the anechoic chamber to find worst frequencies before performing it on an OATS. The initial scan in the 3m Anechoic chamber shows that there are serveral frequencies may be above the limit. So EUT were taken out to test on an OATS. What I would like to know is if you are performing the test on an OATS, unfortunately the abient level for those frequency are very high and it is above your EUT level. What would you do? Would you? 1. Ignore that frequency. 2. Move the EUT to 3m and hope the EUT level is above the abient level. What happened if the EUT is too large to be regarded as "electrical small". 2. Use the 3m semi Anechoic Chambers results -10dB, if this means fail then modify the EUT in the chamber until it passes. 4. Use different OATS. Are they any guideline from the Trade Industry regarding this situation? Any comments are very welcome. Best Regards Vi Van EMC engineer Mitsubishi PC. >
