Why does the filter function in matlab get different results from the IIR filters using direct form?

1. How does the filter function work in Matlab?
2. How to use IIR filter in Matlab?
3. What are the key differences between an FIR filter and an IIR filter?

How does the filter function work in Matlab?

In MATLAB^®, the filter function filters a vector of data x according to the following difference equation, which describes a tapped delay-line filter. In this equation, a and b are vectors of coefficients of the filter, N_a is the feedback filter order, and N_b is the feedforward filter order.

How to use IIR filter in Matlab?

iir = dsp. IIRFilter creates an infinite impulse response (IIR) filter System object that independently filters each channel of the input over time using a specified IIR filter implementation. iir = dsp. IIRFilter( Name,Value ) creates an IIR filter object with each specified property set to the specified value.

What are the key differences between an FIR filter and an IIR filter?

If the impulse response of the filter falls to zero after a finite period of time, it is an FIR (Finite Impulse Response) filter. However, if the impulse response exists indefinitely, it is an IIR (Infinite Impulse Response) filter.