FUNDAMENTAL-FREQUENCY PERTURBATION OBSERVED IN SUSTAINED PHONATION

The middle segments of sustained phonations of /i/, produced by six male adults at f0's ranging from 98 to 298 Hz, were examined for cycle-to-cycle frequency perturbation. The voice samples were analyzed by a peak-picking f0 analysis program (Horii, 1975). The results showed that, between 98 Hz and 210 Hz, mean jitter size decreased as the f0 increased, whereas the coresponding jitter ratios remained relatively constant. Above about 20 Hz, mean jitter remained relatively constant and, consequently, the jitter ratio increased as f0 increased. The problems of temporal resolution for vocal jitter studies, vowel-dependent jitter magnitude characteristics and various perturbation measures are discussed.