FIR vs IIR Digital Filter 


In the realm of signal processing and filter design, understanding the difference between Finite Impulse Response (FIR) and Infinite Impulse Response (IIR) filters is crucial. The impulse response of a filter refers to its output response when subjected to an impulse input. FIR filters have a finite impulse response duration, while IIR filters exhibit an infinite impulse response duration. Additionally, the operation of convolution plays a significant role in filtering operations, applying weighted local averaging to input signals based on the filter's impulse response. Let's delve deeper into the characteristics and implementations of FIR and IIR filters.


FIR Filters                       

As one can see, the FIR filter output response y[n] only depends on input signal x[n].

IIR Filters 

As one can see, the IIR filter output response y[n] depends on both input signal x[n] and y[n].


FIR and IIR filters find numerous real-world applications in various domains due to their distinct characteristics. Here are some examples:

Finite Impulse Response (FIR) Filters:

Infinite Impulse Response (IIR) Filters:

These examples highlight how FIR and IIR filters are integral to a wide range of applications, addressing diverse signal processing requirements across industries. The choice between FIR and IIR filters depends on factors such as desired frequency response, computational complexity, stability considerations, and specific application constraints. The main difference is time delay for the digital filter, for fast realtime output, typically IIR filters are used such as low pass or high pass filters due to lower number of coefficients.