This thesis presents a precompensation methodology for nonlinear distortions due to traveling wave tube amplifiers. Traveling wave tubes add both phase and magnitude distortions to the signal data. The precompensation corrects for these distortions and is accomplished at baseband frequency via a digital system. A BPSK system has been analyzed for system enhancement, as measured by the system parameters of bit error rate, 99% bandwidth, 99.9% bandwidth, and adjacent channel interference. The system parameter measurements show that the precompensation methodology has improved system performance. All data generated is in support of a new digital transmitter under development at NASA Lewis Research Center.