Analog sampled filter
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An analog sampled filter an
discrete, however. Distinct analog samples are shifted through an array of holding capacitors as in a bucket brigade. Analog adders and amplifiers do the arithmetic in the signal domain, just as in an analog computer
.
Note that these filters are subject to aliasing phenomena just like a digital filter, and anti-aliasing filters will usually be required. See Filter design § Anti-aliasing.
Companies such as
Maxim produce integrated circuits that implement this functionality. Filters up to the 8th order may be implemented using a single chip. Some are fully configurable; some are pre-configured, usually as low-pass filters
.
Due to the high filter order that can be achieved in an easy and stable manner, single chip analog sampled filters are often used for implementing anti-aliasing filters for digital filters. The analog sampled filter will in its turn need yet another anti-aliasing filter, but this can often be implemented as a simple 1st order low-pass
.