/Comparison-of-FIR-and-IIR-Filters-in-Noise-Removal

This project focuses on the removal of 400Hz noise from audio files utilizing both FIR and IIR filters.

Primary LanguageMATLAB

Comparison of Noise Removal Using IIR and FIR Filters

This project focuses on removing 400Hz noise from signals using both IIR (Infinite Impulse Response) and FIR (Finite Impulse Response) filters.

Project Overview

FIR Filter

The FIR filter designed for this project exhibits a cutoff frequency range approximately between 350Hz and 500Hz. It has non-uniform attenuation within this band and does not fully attenuate the exact 400Hz frequency, as indicated by a local maximum around 400Hz. The phase response shows a noticeable change around the cutoff frequencies, indicating phase shifts.

FIR Filter Frequency Response

IIR Filter

The IIR filter's frequency response is influenced by two parameters, A and B. Parameter A significantly impacts the depth and intensity within its cutoff range and introduces phase modifications. Parameter B shifts the cutoff range. The values of A and B were chosen through iterative experimentation to maximize the filter’s efficacy at 400Hz.

  • Optimal values for parameters:
    • A = 0.82
    • B = 1.902

IIR Filter Frequency Response

Effect of Parameters A & B

  • A: Affects the depth and intensity of the filter response within its cutoff range and modifies the phase.
  • B: Responsible for shifting the cutoff range.

Comparison of FIR and IIR Filters

  • FIR Filter:

    • Wider attenuation range (350Hz to 500Hz).
    • Non-uniform attenuation within the band.
    • Noticeable phase shifts around cutoff frequencies.

  • IIR Filter:

    • Targets a narrower band centered around 400Hz.
    • Provides a more consistent response outside the 400Hz band.
    • Results in a clearer output signal closer to the original frequencies outside the targeted range.

Reasons for IIR Filter Superiority

The IIR filter demonstrates superior performance in attenuating the 400Hz hum noise due to its targeted narrow band and consistent response. This results in a clearer output signal compared to the FIR filter, which has a broader and less consistent attenuation range.

Importance of FIR Filters

Despite the superior performance of IIR filters, FIR filters remain indispensable due to:

  • Inherent stability.
  • Ability to maintain a linear phase response.
  • Ease of design and optimization.
  • Suitability for applications requiring signal integrity, such as audio and image processing.
  • Robust numerical properties and compatibility with modern DSP architectures.