In the previous section, we presented the main transmitter architecture solutions, from analog to fully digital, and highlighted their main weaknesses. We now describe that DSP techniques can be useful for correction and compensation of TX impairments. Therefore they can have a crucial impact on transmitter architectures viability. We show that in addition to digital implementation, adaptive algorithms are of high interest for unsupervised tuning. We begin with a presentation of a Least Mean Square (LMS) algorithm in the context of RF default compensation. Predistortion and polar transmitter delay correction principles are then exposed. Finally, solutions for crest factor reduction are mentioned.