FCC Test Equipment & Facilities Requirements

Question 1

What is the minimum shielding effectiveness typically required for an RF shielded room used in FCC testing?

Accepted Answer

100 dB attenuation from 10 kHz to 10 GHz

Answer

High-performance RF shielded rooms for FCC testing typically provide at least 100 dB of shielding effectiveness across the measurement frequency range to ensure that external RF signals do not corrupt emission measurements.

Question 2

What type of absorber material is placed on the walls, ceiling, and floor of an anechoic chamber for FCC EMC testing?

Accepted Answer

Pyramidal carbon-loaded polyurethane foam absorbers

Answer

Pyramidal carbon-loaded polyurethane foam absorbers are used in anechoic chambers to convert incident RF energy into heat, preventing reflections that would distort the free-space measurement environment.

Question 3

What is the purpose of a spectrum analyzer or EMI receiver in FCC radiated emissions testing?

Accepted Answer

To measure the amplitude of electromagnetic emissions at each frequency across the test range

Answer

An EMI receiver or spectrum analyzer measures the level of electromagnetic emissions radiated by the device under test across the specified frequency range, providing the data that is compared against FCC emission limits.

Question 4

What is a 'pre-scan' in FCC radiated emissions testing and why is it performed?

Accepted Answer

A fast sweep to identify peak emission frequencies before conducting the slower, definitive final scan

Answer

A pre-scan uses a peak detector in fast sweep mode to quickly identify candidate frequencies where emissions are highest, allowing the time-consuming final measurement to focus on those specific frequencies rather than scanning the entire range.

Question 5

What power supply conditions must be verified when setting up a device for FCC conducted emissions testing?

Accepted Answer

The device must be powered from a nominal AC line voltage with the LISN inserted, operating under its worst-case emission configuration

Answer

The device under test must be powered from a regulated AC source at nominal line voltage through the LISN, and must be placed in its worst-case operating mode (typically maximum processing load) to ensure the highest emission levels are measured.

FCC - Federal Communications Commission Certified Laboratory Practice Test

FCC - Federal Communications Commission Certified Laboratory Practice Test

FCC Test Equipment & Facilities Requirements