Selecting a Sampling Rate (System Identification Toolkit)

LabVIEW System Identification Toolkit

Selecting a Sampling Rate (System Identification Toolkit)

The time constants of a system influence the selection of a sampling rate. Sampling at rates substantially greater than the system bandwidth leads to data redundancy, numerical issues, and modeling of high frequency artifacts likely due to noise. Sampling at rates slower than system dynamics leads to difficulties determining an accurate system model and problems introduced by aliasing. You can use an anti-aliasing filter to counter the effects of aliasing.

A common rule of thumb is to sample signals at 10 times the bandwidth of the system or the bandwidth of interest for the model. If uncertainty exists in the system bandwidth and a fast data acquisition environment is available, you can sample as fast as possible, then use a digital filter and decimation to reduce the sampling rate to the desired value. Decimation is a form of downsampling the data set.