RMS Level of a Signal
The RMS level of a signal is the square root of the mean value of the squared signal. RMS measurements are always positive. Use RMS measurements when a representation of energy is needed. You usually acquire RMS measurements on dynamic signals—signals with relatively fast changes—such as noise or periodic signals.
The RMS level of a continuous signal V(t) from time t1 to time t2 is given by the following equation:
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(A) |
where t2 – t1 is the integration time or measurement time.
The RMS level of a discrete signal Vi is given by the following equation.
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(B) |
One difficulty is encountered when measuring the dynamic part of a signal using an instrument that does not offer an AC-coupling option. A true RMS measurement includes the DC part in the measurement, which is a measurement you might not want.
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