Speech modification by selective Fourier-Bessel series expansion of speech signals

Speech modification for voice disguising and spectrum modifying applications has been explored using a Fourier-Bessel series (FB) expansion of speech signals. With the approximately bandpass spectrum of the first order Bessel functions, the FB expansion coefficients may be altered and the expansion may be truncated to yield a desired speech quality in the modified speech. Results demonstrate that reasonable quality of altered speech at low bit rate coding can be achieved.