Anti-Aliasing Filter

A device that attenuates signal content outside the desired bandwidth. It precedes the analog-to-digital converter (ADC) in instrumentation designs theoretically allowing only frequencies in the pass-band to be sampled by the ADC.

It consists of a low pass filter designed to stop frequencies higher than the half the sample rate, in order to minimize aliasing.

Anti-alias filters are specified according to the sampling rate and so if you change the sampling rate the anti-aliasing filter changes frequency as well.

There must be one filter for each input channel.

See also: Alias, Aliasing, Analogue to Digital converter, Low Pass Filter, Nyquist Frequency.

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Subjects: Noise & Vibration Signal Processing