Comparison of Multirate two-channel Quadrature Mirror Filter Bank with FIR Filters Based Multiband Dynamic Range Control for audio

Abstract

This paper proposes a Comparison of Multirate two-channel Quadrature Mirror Filter QMF bank with FIR filters based Multiband Dynamic Range Control DRC for audio. Two-channel QMF decomposes input audio signals into low and high frequency bands with the help of analysis filters, and these sub-bands are decimated by a factor of 2 and inputted to DRC up-sampled by a factor of 2 after which need to be combined to reconstruct the original signal with the help of synthesis filters with increased amplitude in the audio compared to when only FIR filters are used. The filters used here are Finite Impulse Response FIR using Kaiser Window. The reconstructed signal is an exact replica of input signal with some delay called perfect reconstruction. In DRC, multi-band compressor is used to apply compression differently to different frequency bands of the input signal, which uses minimum gain method. This allows the user to be selective about how compression is applied to a signal and only add power to certain parts of the frequency spectrum. Here limiter, compressor, expander and noise gate are used in the DRC, which protects the AD converter from overload. Index Terms: Analog to digital converter (A/D), Dynamic Range Control (DRC), Finite Impulse Response (FIR), Quadrature Mirror Filter (QMF).