COMPLEX WAVEFORM GENERATOR                      SCOTT GRAVENHORST
06-30-96                                  chordman@concentric.net

Note: Drawing names within the drawings specify .BMP because 
they are BMP files in my system.  For conservation of space, they 
are saved in the archive as GIF.

This device uses an XOR feedback shift register of 4 bits to 
generate 15 different repeating patterns of bits.  The bits are 
translated to analog levels and are mixed and amplified.  
Twisting the mixer knobs changes the characteristic sound quite 
profoundly.  Exactly what any knob does is interdependant on the 
rest of the knob and switch settings.  The switches control the 
pattern being generated and the pots control the level and phase 
of the ever toggling parallel outputs of the shift register.  The 
pattern selected will also perform an inherent divide down of the 
VCO clock to it.  For example, you can select a pattern that has 
3 states in it's sequence.  This selection would provide a 
complex waveform with a division factor of 3.  The VCO would be 
running at 3 times the waveform frequency, giving a nice perfect 
fifth relationship.  The input was designed to be driven by the 
VCNGVCO [linear.VCO] system, which is a FatMan compatible VCO with a 
CMOS clock driver.  The output circuit was designed to drive a FatMan 
by connecting the output to IC17 pin 3.  It would be better, 
however, to build and connect through a FATMIXER.  The schematics 
for these are in or near the same place you found this.  The 
"reset" switch is there in case you generate an all ones pattern 
in the shift register.  This will cause the generator to be 
silent.  Once reset, the XOR feedback system will function 
continuously until the switches are again changed.  I find the 
need to use this switch rare.  

Power supply design, bypassing and connecting unused CMOS inputs 
to a rail is your responsibility and is left out of all of my 
schematics to keep them cleaner and more easy to read.  

If you build this, please send comments, good and bad to me:
chordman@concentric.net.  (I used to be chordman@ix.netcom.com)