Schematics / PLLFREQUENCYMULTIPLIERMODULE
PLL FREQUENCY MULTIPLIER MODULE By Scott R. Gravenhorst Originally designed for PAiA FatMan
From the description Scott gives on his page http://home1.gte.net/res0658s/fatman/4046pll.html :
This circuit is a multi purpose phase locked loop designed for frequency multiplication (harmonic generation). Although it was designed around a PAiA FatMan, it should be adaptable to almost any analog system. The circuit is based on a 4046 type micropower phase locked loop IC and uses a divide by 12 counter inserted in the loop to force the PLL's VCO to run at 12 times the input frequency. It's output is provided as a set of 7 different square waves representing octaves and perfect 5th harmonics of the input signal. If you build this for a system other than the PAiA FatMan, you must design an appropriate attenuator or amplifier, whichever is necessary for your system or mixer. This should be fairly simple, being not much more than a voltage divider (attenuator) or an Op Amp buffer.
Much like a VCO (or in this case, 7 VCOs), this is a sound generating module, intended to enhance a synth by tracking a VCO to produce it's own waveform at 7 different harmonic frequencies. Wherever the source VCO's pitch goes, so does the phase locked loop. Because it is a phase locked loop, it has characteristics of it's own, such as controllable lag and over/undershoot when the input frequency changes.
The circuit works for a FatMan as designed and drawn. If you are building this for a system other than a FatMan, you may need some kind of conditioning for the 4046 input, such as a schmitt trigger or op amp or both. This circuit works well with a -12V pulse or square wave (pulsating DC, negative going) input.
Here is a list of some harmonics and their interval relationship back to the fundamental:
2f 1 oct 3f 5th + 1 oct 4f 2 oct 5f maj 3rd + 2 oct 6f 5th + 2 oct 7f min 7th + 2 oct 8f 3 oct 9f 9th + 3 oct 19f minor 3rd + 3 oct 27f 6th + 4 oct
visit http://home1.gte.net/res0658s/fatman/ for more additional schematics and modifications for Paia Fatman