Role of Biquad and Hilbert Filters in Removing Noise – A Simulink Analysis

Often some noise signals get interleaved with speech signals and owing to noisy surroundings the captured signal may not sound as desired. For such cases, a combination of Hilbert transform filter and Biquad filter in cascaded form might prove helpful. An arrangement in a simulink model demonstrates successful noise reduction in a voice signal recorded from a microphone. Both the filters used were of Direct Form structure, while the Hilbert filter was a Direct Form FIR, the Biquad was Direct Form II structure filter. The observations for speech signal as well as noise signals have been produced as results that show a significant noise removal.