Details in Portuguese here, Googlish here.
"The synthesis system sound (tone generator) was based on a panel of 16 slide switches, through which it was possible to "draw" the waveform. The positions of the keys were encoded in 4 bits per pixel, and could be stored in memory. This allowed quick access to various preset voices, during operation.
Then, the keyboard was developed. We left 12 LC generators individually tunable, which were selected and divided by the circuit of the keyboard, resulting in a final frequency that was sent to the tone generator. The oscillators used diodes "varicap" and accept an input of frequency modulation to provide vibrato.
Keys, wood, were achieved by Celso in Diatron (factory electronic organs). The contacts were taken from telephone relays.
To allow "glissandos" and behavior, we developed an innovative circuit "Phase Locked Loop" control exponential VCO. Thus, it was maintained the accuracy and stability of digital oscillators but providing linear behavior musical scale (logarithmic).
The other processing modules (filters, VCA, envelope generators) were basically analog, can receive commands from a computer via D / A converters for general use..."
via modular.br on Facebook
