FPGAs have become an increasingly important resource for software radio systems. Programmable logic technology now offers significant advantages for implementing software radio functions such as DDCs . For many applications, this implementation shift brings advantages that include higher precision processing, higher channel density, lower power, and lower cost. This handbook introduces the basics of FPGA technology and its relationship to Software Defined Radio (SDR) systems. A review of Pentek’s GateFlow FPGA Design Resources is followed by a discussion of features and benefits of FPGA-based DDCs. The latest Pentek SDR products that utilize FPGA technology and applications based on such products are also presented.