Error analysis in angular frequency propagation method caused by using the DFT

The authors analyze the errors that arise in the numerical evaluation of the continuous convolution integral using the discrete Fourier transform (DFT). They focus on the numerical evaluation of Rayleigh´s integral using the angular frequency propagation method, which furnishes a good example of the occurrence of such error. Aliasing error, warp-around error, circular convolution, and the windowing effect are discussed. Methods for reducing error are suggested