Interfering DC Component, Suppression and Influence to Digital Signal Processing

Abstract

The article concentrates on effects of a digitized audio signal DC component on a typical A/D converter and its influence on further signal processing. This article analyses reasons of the interfering DC component emergence in the A/D converter. Results of the measurement made on Analog Devices converter are presented. The DC component can adversely affect a series of signal processing algorithms such as algorithms for maintaining stable level of signal (e.g. leveler algorithm). The article examines the possibility of a DC component removal by digital filtering. Attention is focused on the choice of a suitable filter type and its parameters in order to avoid any destruction of a transmitted signal, e.g. due to poor group delay characteristic, or by suppressing low frequencies in the filter.