Difference between IIR and FIR Filters

August 2022 · 3 minute read

IIR and FIR filters are the two most common types of digital filters. But what’s the difference between them? In this article, we’ll take a look at the key differences between IIR and FIR filters, and discuss when each type is best suited for use. Stay tuned!

What is IIR Filter?

IIR filters are digital filters that have an infinite impulse response. IIR filters are used in many applications where it is required to remove noise or unwanted signals from a digital signal. IIR filters have two main advantages over IIR filters. IIR filters have a linear phase response, which means that the phase distortion introduced by the IIR filter is constant over the entire frequency range. IIR filters also have a constant group delay, which means that the time delay introduced by the IIR filter is also constant over the entire frequency range. IIR filters are usually designed using a windowing method such as the Parks-McClellan algorithm.

What is FIR Filter?

FIR filters are a type of digital filter that is commonly used in audio processing. FIR stands for “finite impulse response”, and refers to the fact that FIR filters have a finite number of taps or coefficients. FIR filters are also sometimes referred to as “all-zero filters”, due to the fact that they have no poles (zeros) in their transfer function. FIR filters are generally very versatile and can be designed to achieve a wide variety of frequency responses. FIR filters are also relatively simple to implement and can be easily parallelized for efficient implementation on DSP hardware. However, FIR filters generally have a longer delay than IIR filters and can require more computational resources.

Difference between IIR and FIR Filters

IIR and FIR filters are both digital filters that are used to process digital signals. IIR filters are Infinite Impulse Response filters, while FIR filters are Finite Impulse Response filters. IIR filters have feedback, which means that they use past input samples to calculate the current output sample. FIR filters do not have feedback, which means that they only use present and past input samples to calculate the current output sample.

IIR filters have a shorter impulse response than FIR filters, but they also have a greater exponentiating decay. This means that IIR filters can better approximate certain types of signals than FIR filters can. However, IIR filters also have a greater potential for instability than FIR filters do. As a result, FIR filters are typically used when stability is more important than approximation quality.

Conclusion

Although both IIR and FIR filters have their pros and cons, FIR filters are generally the better option when it comes to audio filtering. They offer a cleaner sound with less distortion, making them perfect for use in music production and other audio applications. If you’re looking for a high-quality filter solution for your next project, we recommend using an FIR filter.

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