1.4 Anti-aliasing Filter
The forth block of the measuring system (Fig. 1.1) is a low-pass anti-aliasing filter. It removes all harmonics of the measured signal that exceed the Nyquist frequency. An aliasing error is produced when the sampling frequency is not at least twice as high as the highest measured signal frequency and the overlap between those frequencies appears. Fig. 1.2 shows spectrum diagrams explaining the overlap and the causes of aliasing error.
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