Direct Method for Bispectrum Estimation

The direct method serves as an accessible technique for bispectrum estimation, featuring clear implementation logic that makes it ideal for beginners. Its fundamental approach involves computing signal autocorrelation and cross-correlation functions directly to derive bispectrum estimates. The method's effectiveness relies on proper processing of these correlation functions, which contain essential signal information. Through straightforward mathematical operations—typically implemented using functions like xcorr() for correlation computation and fft() for Fourier transforms—the direct method can generate reasonably accurate bispectrum results. For code implementation, beginners can structure the algorithm by first calculating third-order moments or correlations, followed by applying multi-dimensional Fourier transforms. This makes the direct method an excellent starting point for those learning bispectrum estimation techniques, as it demonstrates core concepts without requiring advanced signal processing knowledge.