TIME VARYING OVERALL LEVEL
By Dr Colin Mercer, Technical Director, Prosig
A common requirement in noise and vibration analysis is to find the overall level of a signal as a function of time. Now the overall level is a measure of the total dynamic energy in the signal. That is it does not contain the energy due to the DC level, which is the same as the mean value. The overall level is often loosely referred to as the signal RMS value. However the formal definition of the RMS level is that it contains the DC level as well as the dynamic energy level. If only the dynamic contribution is required then the measure needed is, strictly speaking, the Standard Deviation (SD). Sometimes it is useful to refer to the SD as the Dynamic RMS. read »»»
