Study of polyphase structure made easy using GNU Radio

Our current education system lacks in providing visualization of concepts, without which the learning process is incomplete. Particularly, in case of complex signal processing algorithms, visualizing is very difficult or almost impossible. The aim of this paper is to understand and provide visualization of the basic concepts of multirate signal processing using low cost computing platform, GNU Radio. Multirate signal processing has a significant influence at the physical or hardware layer of modern communication systems. In real, multirate signal processing is found at the core of communication systems that couple the Software Defined Radio (SDR) and Software Communications Architecture (SCA) to reconfigure system resources for operation over a wide range of modulation formats and waveforms. In multirate systems, polyphase structure plays an important role in reducing the computation rate by noble identities. The parallel processing makes it very efficient in implementation architecture. GNU Radio companion is an open source graphical simulation tool which we utilized for better understanding of complex signal processing concepts. In our paper we have implemented simple multirate signal processing building blocks.