Digital Signal Modulator on FPGA Using on the Fly Partial Reconfiguration

Communication receivers supporting multiple standards and modulation techniques are thirst of the time. Military has initiated technology like Software Defined Radio (SDR) which supports various network types and demodulation techniques. To test such devices all types of modulators which can source all possible test inputs for such receivers are needed. Instead of using off-the-shelf but costly instruments to test various communication systems, FPGA-based Digital signal modulator (DSM) is cost-effective solution. The paper discusses the effectiveness of using Partial Reconfiguration (PR) feature of FPGA for FPGA based DSM. Availability of more modulators in DSM demands more FPGA resources, but in testing set up only one type of modulator of DSM is required at any point of time. Hence the resources utilized by other modulation techniques become overhead. In order to reduce this overhead PR is an ideal solution. As a case study an implementation scheme of QAM and QPSK modulators using difference based PR on xc3s400-5pq208 device is presented. Results of the implementation are included in the paper. Result indicates use of PR will allow realization of versatile DSM on small FPGA.