Single pole IIR filter, fixed point design

1. What is fixed point filter?
2. Why are IIR filters not stable?
3. What is the advantage of designing IIR filters using pole zero plots?

What is fixed point filter?

Fixed-point filters are commonly used in digital signal processors where data storage and power consumption are key limiting factors. With the constraints you specify, DSP System Toolbox™ software allows you to design efficient fixed-point filters. The filter for this example is a lowpass equiripple FIR filter.

Why are IIR filters not stable?

(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.

What is the advantage of designing IIR filters using pole zero plots?

This is useful for illustrating how the filter causes impulsive inputs to spread out in the time domain. The magnitude and phase plots show and , respectively, plotted with so that the frequency ranges from up to , which are the minimum and maximum frequencies representable in a digital system.