30-MHz attenuation standard using binary phase modulation method

Abstract

A 30-MHz attenuation measurement system which uses a ratio transformer as the standard attenuator is constructed and examined. The binary phase modulation method is used. Higher accuracy at low attenuations and easier maintenance are expected in the system than in the conventional system using the piston attenuator. The estimated uncertainty of the system is 0.0015 dB for 0-20 dB. The attenuation measurements made by the system and the conventional system agree within the estimated uncertainties. >