User Manual

3.11 FFT Definitions
107
Anti-Aliasing Filters ____________________________________________
When the maximum frequency component of the input signal is higher than one-
half of the sampling frequency, aliasing distortion occurs. To eliminate aliasing
distortion, a low-pass filter can be used that cuts frequencies higher than one-
half of the sampling frequency. Such a low-pass filter is called an anti-aliasing fil-
ter.
The following figures show the effect of application of an anti-aliasing filter on a
square wave input waveform.
Non-existent frequency components are observed.
Without an anti-aliasing filter
With an anti-aliasing filter