Design and VLSI Implementation of Oversampling Sigma Delta Digital to Analog Convertor Used For Hearing Aid Application
S. Tamil Selvi · 2015
Signal processing of present era is becoming more and more complex day by day. To meet the demand of modern signal processing, emphasis has been given to develop systems with minimum hardware. As a matter of fact, reduction in hardware complexity of digital filter has emerged as one of the upcoming research areas in present time. The most basic interpolation system for integer up sampling cascades an expander unit with an interpolation low pass filter .The low pass filter is used to remove the unwanted spectral images caused due to up sampling .The proposed system uses an half band elliptic IIR low pass filter implemented as a parallel connection of two all pass filter sections and sigma delta modulators to implement the Digital To Analog Convertor(DAC). The filter coefficient implemented using only adders / shifters. The method described here is intended for quick design at the system level without the use of intensive calculation. The design aims to provide low computational hardware when compared to other filters.