  In this paper, a phase improvement algorithm has been developed to design the
nonlinear frequency modulated (NLFM) signal for the four windows of
Raised-Cosine, Taylor, Chebyshev, and Kaiser. We have already designed NLFM
signal by stationary phase method. The simulation results for the peak sidelobe
level of the autocorrelation function in the phase improvement algorithm reveal
a significant average decrement of about 5 dB with respect to stationary phase
method. Moreover, to evaluate the efficiency of the phase improvement
algorithm, minimum error value for each iteration is calculated.
