Digital Filters for Sigma-Delta Modulation in Wireless Communications

This paper presents the effect of digital filtering in a sigma-delta modulation (SDM) used in wireless communications. SDM is widely used in digital-to-analog conversion because it offers high signal to noise ratio and distortion rate and low power and costs. SDM uses oversampling and noise shaping in order to move quantization noise from the signal band end and to eliminate it through a low pass filtering process. A SDM based scheme was implemented in a wireless communications system. Simulations were performed for different oversampling rates, digital filter types and communications channels. Bit error rate (BER) was used to evaluate the performances of the system.