antialias filter with multirate system?

Question

How can I use matlab for my antialiasing filter to simulate it?

Answer 1

A true anti-aliasing filter is, and must be, an analog filter. The numbers in Matlab are already sampled discrete-time signals, there is no way to provide an analog filter to a sampled number. Even the continuous-time functions operate on discrete time signals, using numerical methods to perform the function.

.