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Exam 1999 Question 6

"Describe how distributions of fundamental frequency use may be obtained from laryngographic analysis. Discuss the problems of obtaining a reliable indication of fundamental frequency range from laryngographic analysis. Discuss the relative advantages of the laryngograph over narrow-band spectrograms for the study of intonation contours."

20 things you should mention:

  • Laryngograph
    • Lx waveform for monitoring current flow
    • Tx = individual period estimates
    • Fx = calculated from Tx of each cycle
    • can have Fx display versus time
    • build a histogram of Fx usage
    • from (say) a read passage
    • Dx1 includes all frequencies
    • Dx2 includes only regular voicing
    • Cx shows regular and irregular
    • - pictures
  • Range problems
    • standard deviation problems
    • - affected by outliers
    • outliers caused by low-frequency creak (typically)
    • better to use percentile-based measures
    • 90% range better
    • measuring max-min on Fx display also susceptible to errors
  • c.f. Spectrogram
    • spectrograph: contaminated by noise
    • difficult to see harmonics for low-pitched voice, can't get period-by-period estimates
    • doesn't need special equipment
    • direct, reliable, automated analysis

© 2000 Mark Huckvale University College London