LabVIEW Signal Processing

Appendix C Frequently Asked Questions

Background

1. Can the antialiasing filter be a digital filter?

In general, when going from a domain P to a domain Q, the filter should be in domain P to avoid the problem of aliasing in the domain Q. Thus, when sampling to convert an analog signal to a digital signal, the antialiasing filter should be an analog filter. However, when performing decimation to reduce the sampling rate, you are going from the digital domain (with a higher sampling rate) to the digital domain (with a lower sampling rate). In this case, the filtering before the decimation is performed in the digital domain by a digital filter. ...