Measurement of the Amplitude and Phase of FM Noise Currents on a Personal Computer Chassis

IT equipment mostly uses dithered clocks, radiating FM noise especially in the frequency range above 1 GHz. Investigations are carried out to measure the noise source current flows on a PC chassis. Since network analyzers are useless for measurement of FM noises, a six-port junction is developed and used with a pair of loop antennas. This instrument can display current flows of PC harmonic noises