Given the DSP system, where the sampling rate of 4000 Hz is used, the anti-aliasing filter is the Butterworth filter with a cut-off frequency of 200 Hz, and the percentage of aliasing level at the cut- off frequency is required to be less than 10%, determine
a. the order of the Butterworth type LPF filter
b. the aliasing noise level for the selected the filter order from 1) at 100 Hz