FCC will accept data compared to the EN55022A or B limits in lieu of the limits detailed FCC Part 15. The test method to be used is ANSI C63.4, however, which does have minimum system configurations (unlike EN55022) for Class B PC peripherals. If selecting this route then, as has been noted by others in this forum, both radiated AND conducted tests need to be performed against the EN55022 limits (i.e you will need to extend the frequency range of conducted down to 0.15 MHz). In addition if the EUT uses or generates a signal above 108 MHz then the upper frequency range of the radiated emissions tests has to be extended to meet the requirements of FCC Part 15, with the limits being taken from FCC Part 15 for the frequencies that are out of the scope of EN55022.
Someone asked the question "what if I meet EN but not FCC?" My answer would be that if you are that close to the EN55022 limit then your compliancy status is probably questionable - given that the measurement errors associated with radiated testing are typically between 3 and 4 dB and the difference between the two limits are generally less than this. My opinion aside, there is no problem with meeting the requirements of CISPR22 in lieu of FCC Part 15 so theoretically you can sell in the US if you meet one set of limits for both conducted and radiated emissions but not the other. Regards, Mark
