# Averaging to Improve the Measurement

Instantaneous DC measurements of a noisy signal can vary randomly and significantly, as shown in the following figure. You can measure a more accurate value by averaging out the noise that is superimposed on the desired DC level. In a continuous signal, the averaged value between two times, t1 and t2, is defined as the signal integration between t1 and t2, divided by the measurement time, t2 – t1, as shown in the following figure.

The area between the averaged value Vdc and the signal that is above Vdc is equal to the area between Vdc and the signal that is under Vdc. For a sampled signal, the average value is the sum of the voltage samples divided by the measurement time in samples, or the mean value of the measurement samples.

An RMS measurement is an averaged quantity because it is the average energy in the signal over a measurement period. You can improve the RMS measurement accuracy by using a longer averaging time, equivalent to the integration time or measurement time.

There are several different strategies to use for making DC and RMS measurements, each dependent on the type of error or noise sources. When choosing a strategy, you must decide if accuracy or speed of the measurement is more important.