Explanation of the various KPE buttons and parameters
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Parameter buttons:
- resonators
    F1-F6:   formant frequencies
    A1-A6:   formant amplitudes
    B1-B6:   formant bandwidths
    B1P-B6P: formant bandwidths of the parallel branch
    FNZ:     nasal zero frequency
    BNZ:     nasal zero bandwidth
    FNP:     nasal pole frequency
    BNP:     nasal pole bandwidth
    ANP:     nasal pole amplitude
- voice source parameters
    KO:      glottal open quotient
    AT:      breathiness
    TL:      spectral tilt
    SK:      skewness (speed quotient) of voiced excitation signal
    FX:      fundamental frequency
- excitation amplitude parameters
    AV:      amplitude of voicing (modulated glottal airflow, AC component)
    ASP:     amplitude of aspiration
    AF:      amplitude of frication
    AFP:     amplitude of bypass path (parallel branch)
    AVP:     amplitude of voicing (parallel branch)
    GA:      overall signal gain
- global settings
    DU:      duration of (selected) waveform
    UI:      update interval for parameter reset
    SR:      sampling frequency
    NF:      number of formants
    SS:      voice source; 1 = impulse, 2 = natural, 3 = sampled
    CP:      1 = cascade + parallel branches, 2 = parallel only

These don't need any further explanations, do they?
- New, Exit, Redraw, Zoom/Unzoom, Upsize/Downsize/Original size
- Load (parameters or waveforms)
- Save (parameters)
- Spectrum / Smmothed spectrum
- Calc FX: calculate fundamental frequency

General behavior:
- waveform and spectrum colors: blue = original, red = synthesized
- one click on a parameter button displays the parameter and its value
- second click makes the parameter available for modification,
  explanation of selected parameter is displayed
- third click removes the parameter from the display
- Hide All: hide all parameters
- Recall: undo last modification(s)
- use the arrows to change parameter values globally
- grab the displayed parameter with the mouse and redraw the
  trajectory to change parameters locally or dynamically
- Synthesise: synthesize new waveform

Waveform and spectrum:
- middle mouse button plays waveform
- bracket a section of the waveform by clicking the left mouse button
  to set the left border and the right button to set the right border
- to obtain a smoother spectrum, select approx. 3 fundamental periods
  of the waveform