Generation of Constant Envelope Signals

In a paper, "Constant Envelope Bandlimited BPSK Signal," Yazdani et al. introduced a technique for the generation of a constant envelope signal by the addition of separately generated inphase and quadrature signals. Their scheme utilizes a nonlinear approximation to the quadrature signal ahd requires hard limiting to achieve a constant envelope. This correspondence suggests an alternate approach which does not require hard limiting and, thus, eliminates the spectral spreading associated with the limiting process.