Nonlinear Signal Processing for Advanced Digital Receive Systems

GMR Research & Technology (GMR) proposes to investigate digital methods to compensate for nonlinear distortions in RF receivers including all components. In particular we will address harmonic distortions caused by amplifiers, mixers, and Analog-to-digital converters (ADCs). In particular we propose to investigate the combined techniques of digital nonlinear equalization of harmonic distortions (NLEQ) and of digital equalization of interleaved modalities (iNLEQ). These two techniques use similar underlying algorithms and are complementary to each other. In conjunction these techniques have the potential for reducing spurious signals and expanding the bandwidth of receiver systems. In the first phase of the SBIR effort we will develop this approach for a receiver system determined by the government in conjunction with GMR. We will verify the approach through software simulation. In the second phase of the SBIR effort we will design, build, and test a digital receiver which will incorporate our nonlinear signal processing approach on a field programmable gate array (FPGA). We expect this type of receiver to have many benefits for the military by significantly increasing the linear dynamic range of receiver systems such as radars and SIGINT platforms. Moreover we expect this solution to be relatively inexpensive and easy to implement.