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

Formants:

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

Bandwidths:

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.

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