More about Averaging

Created on 2012-11-08 17:34:00

The Acoustic Response and Signal Analyzer measurements use averaging to reduce noise in measurement results. This technique averages the signal over a specified number of acquisitions by summing the signals from all acquisitions and dividing the result by the number of acquisitions.


Synchronous averaging

Synchronous averaging operates on a time domain acquisition. Synchronous averaging is useful to examine coherent time domain waveforms by reducing the average level (but not the variance) of noise and other non-coherent signals. Since the frequency domain results in a measurement are derived from the time domain acquisition, synchronous averaging affects spectrum results as well.


Power averaging

Power averaging (spectrum averaging) operates only on a frequency domain result. The power spectra for all averaged acquisitions are summed and then divided by the number of acquisitions. Power averaging helps reveal coherent frequency components by reducing the variance (but not the average level) of noise and other non-coherent signals.


Application in APx500

Synchronous averaging is available to all the results in the Signal Analyzer measurements, when using a Generator Waveform file as the stimulus signal, and triggering from the generator. The generator waveform is looped end-to-end for playback in the generator, and each repetition is synchronously acquired and added to the averaging process.

Synchronous averaging is also available to all the results in the Acoustic Response measurement.

Power averaging is available to the Signal Analyzer FFT Spectrum, Amplitude Spectral Density and Power Spectral Density results, and to the FFT Monitor.

Averaging acquisitions from 2 to 1000 are available. A selection of 1 disables averaging.