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Phonetics Laboratory
Faculty of Linguistics, Philology, and Phonetics

Parameter generation and synthesis

After phonetic interpretation, a parameter file for the Klatt synthesizer (Klatt 1980) is generated:

  • for each 5 ms interval, the exponency database is queried for values for the various synthesis parameters at that particluar point in time
  • if no value for a parameter has been specified by rule, a default value is substituted


The following parameters are updated every 5 ms:

Source parameters

  • AV - Amplitude of voicing
  • AF - Amplitude of frication
  • AH - Amplitude of aspiration
  • AVS - Amplitude of sinusoidal voicing
  • F0 - Fundamental frequency of voicing


  • F1 - First formant frequency
  • F2 - Second formant frequency
  • F3 - Third formant frequency
  • F4 - Fourth formant frequency
  • F5 - Fifth formant frequency
  • FNZ - Nasal zero frequency


  • B1 - First formant bandwidth
  • B2 - Second formant bandwidth
  • B3 - Third formant bandwidth

Parallel branch amplitudes

  • A2 - Second formant amplitude
  • A3 - Third formant amplitude
  • A4 - Fourth formant amplitude
  • A5 - Fifth formant amplitude
  • A6 - Sixth formant amplitude
  • AB - Bypass path amplitude

Not all parameters need to be controlled simulaneously. For example, the parallel branch amplitudes are used to shape the spectrum of frication noise, and need only be specified in the presence of fricative consonants and plosive bursts.

Arthur Dirksen / adirksen@prl.philips.nl / January 1995