Speech zero-crossing rate compression for bandwidth compression
W. Done, Rodney Lynn Kirlin · IEEE Transactions on Acoustics Speech and Signal Processing · 1975
As analysis performed on a proposed special purpose hearing aid yields data on single-sidebanded voice zero-crossing rates extracted by a phase-locked loop (PLL), and also data on the logarithmically compressed voltage analog of the zero-crossing rate. The PLL demodulation is shown to correspond well with first and second formats of the eight vowels analyzed. Three fricatives were also investigated.