# Root Mean Square (rms)

This is the square root of sum of squares of individual observations divided by the total number of observations made.

The r.m.s. value of a function, x(t), over a time interval between t_{1} and t_{2} is specified by the following formula:

Because energy varies as the square of amplitude, rms tracks the amount of energy in a complex signal. In noise data, the rms value should be approximately the same as the standard deviation.

The simple 3 step process to calculate the RMS is:

- square all the individual entries
- average the numbers you get
- take the square-root of that average

### Overall RMS Level

A measure of the total RMS magnitude within a specified frequency range.

**See also: **Crest Factor.

**Subjects: ** Signal Processing