This paper focuses on nonlinear effects on both amplitude and phase of a Chirp signal

and also on pre-compensation method for removing these effects.In a radar system

working distance is mainly decided by transmitted power

the more the power

the longer distance the radar can detect.High power amplifier (HPA) often works at saturation point in order to get high output power

but brings on nonlinear effect on output radar signal.The nonlinear effect degrades the performance of Chirp signal greatly.We analyze the main lobe width and first side lobe due to these effects.We propose two methods for pre-compensation based on DDS

i.e.table-checking method and iterative method.Theory and simulation results show thatthese two methods reduce these effects efficiently.Finally

we analyze the factors that influence the performance of these two pre-compensation methods

as well as the convergence issue for the iterative method

and compare their results.