Comparative study of applications of square root raised cosine filter and low pass filter in Digital Down Converter

Digital Down Converter (DDC) is one of the key technologies in Software Defined Radio (SDR), where a pair of shaping filter and matched filter are required to satisfy the Nuquist up/down sampling condition. Since an appropriate choice of the filter pair affects the DDC performance, this paper studies and compares two kinds of filters, i.e., the square root raised cosine filter (SRRC) and the low pass filter (LPF). The computer simulation is done and the comparison is made in terms of pass-band ripple, stop-band attenuation, inter symbol interference (ISI), and the fix-point bit error rate (BER).