Digital Compensation for Distortion

"Over the past six months as part of a Phase I SBIR, Linearizer Technology, Inc. has been involved in the research and development of a digital signal processing system for signal synthesis and distortion correction to be used with UHF/microwave high poweramplifiers. During this period an approach employing a multi-signal synthesizer and Cartesian lookup tables in an open loop configuration was selected for initial implementation. A unique algorithm for predistortion that can be parameterized by a PC wasdeveloped. Simulations indicate that carrier-to-intermodulation ratios (C/I) > 65 dB can be achieved with this system. A design in Xilinx logic was completed and prototype hardware capable of demonstrating system performance was fabricated. During PhaseII, performance will be enhanced and the initial prototype will be transformed into an integrated unit that can be successfully marketed to manufactures of amplifiers and RF/microwave systems needing linear performance superior to the level that can beachieved with analog linearizers.BENEFITS: Over the past ten years, Linearizer Technology, Inc. has specialized in the solution of problems involving all aspects of non-linearity in communication systems. As customers presented applications requiring C/Igreater than 50 dB but with limited bandwidth, as well as projects utilizing the newer, more cost effective LDMOS components, it became evident that a digital approach to linearization