Considerations for identification of prominent discrete tones of time-varying noise of ITE

摘要

Noise test codes for ITE (information technology equipment), ISO 7779 and ECMA-74 specify,in their informative annex D, two metrics for prominent discrete tones; tone-to-noise ratio andprominence ratio. Both of these metrics have a basic assumption so that the noise emission ofquestion is stationary and can be characterized by only single time-averaged spectrum during theoperation of interest. However, some real noise emissions of ITE occasionally are apparentlynon-stationary, and raise some related issues. This paper discusses the possibility to expand theprocedures to time-varying noise from ITE.