Digital filters

Section: Filtering
  • Ideal filters can be implemented in the frequency domain (but not in real time)
  • FIR filters are stable, but need a lot of coefficients
  • IIR filters can be unstable, but accurate.

IIR filter

  • Recursive filters !

We look for $y$ like: $$ y[t] = \sum_{n=0}^M b[n] x[t-n] - \sum_{n=1}^N a[n] y[t-n] $$

Classical filters

  • Butterworth
  • Tchebychev I, II
  • Elliptical