Impulse response resampling IIR aproximation vs windowing

1. Which is best FIR or IIR?
2. What is IIR system in dsp?
3. Is a Butterworth filter FIR or IIR?
4. Why IIR filters are unstable?

Which is best FIR or IIR?

The advantage of IIR filters over FIR filters is that IIR filters usually require fewer coefficients to execute similar filtering operations, that IIR filters work faster, and require less memory space. The disadvantage of IIR filters is the nonlinear phase response.

What is IIR system in dsp?

Impulse invariance is a technique for designing discrete-time infinite-impulse-response (IIR) filters from continuous-time filters in which the impulse response of the continuous-time system is sampled to produce the impulse response of the discrete-time system.

Is a Butterworth filter FIR or IIR?

The classical IIR filters, Butterworth, Chebyshev Types I and II, elliptic, and Bessel, all approximate the ideal “brick wall” filter in different ways.

Why IIR filters are unstable?

(a) Stable IIR filter, (b) The same IIR filter becomes unstable due to rounding effects. , one poles lie exactly on the unit circle (ie, it is just out of the region of stability) and hence it is an unstable IIR filter.