Installed and Working:

• FatMan VCF External Input
• FatMan VCF Input Mixer
• FatMan New Hard Sync
• Add-on ADSR
• FatMan SubHarmonic Gen.
  • CMOS version (preferred)
  • Perfect 5th Generator
• FatMan VCO Pitch LFO
• FatMan Pulse Width Modulation
• A simple LFO

• Complex Harmonic Gen.
• PLL Perfect Fifth and Octave Gen.
• Linear VCO and CMOS Clock Driver
• VCO with PWM and Tri SubOctave
• CMOS Saw to Tri Converter     - - -    DEMO MP3

• VCF mod adds LFO to AR/ASR switch
• Add Fine/Coarse control for pitch
• Add a switch to swap the ASR and ADSR

Samples

FPGA Stuff:

• FPGA Synthesizer "GateMan I", finished MIDI digital monosynth inspired by the structure of the PAiA FatMan (4 NCO). See the Wiki section at the FPGA synth website.
• "hello world" projects as well as a rudimentary proof of concept MIDI synth.
• Digital waveguide research has turned into an 8 voice polyphonic MIDI synth I call PolyDaWG/8. It uses FPGA internal resources to create one dimensional strings using the Karplus-Strong single delay line theory. See: www.fpga.synth Digital Waveguide Wiki article where the research is blogged from a single waveguide experiment to a 6 string and then finally an 8 string polyphonic harp. The next step is to incorporate the on-board SDRAM to implement the strings. This could provide a harp of 12 to 24 strings and free up the internal FPGA RAM resources for other features. The sample rate of the 8 string synth is 250 KHz, this is necessary because of the length of the strings (delay lines). Longer delay lines mean more tuning accuracy over a wider range, but longer strings also require faster sample rates to maintain pitch range. Faster sample rates, however present a limitation in how much time is available to compute the next sample for output. Currently, the 8 string synth runs with a system clock of 50 MHz, each string requires about 6 clocks plus one for startup, so there it should be possible to stretch from 8 to 12 strings without changing the system clock. To do 24 may require raising the system clock to 100 MHz. 48 strings would require 200 MHz, which the _chip_ can do, but would require much closer attention to timing detail.
• BassDaWG/4 is a modified version of PolyDaWG/8. I found it easy to modify the design and the MIDI controller to support 4 strings that are twice as long. I kept the sample rate at 250 KHz so that the instrument will be one octave below PolyDaWG/8. There are also other optimizations to support using BassDaWG/4 as a bass instrument. Since it is also polyphonic, bass chords commonly used in many forms of music are possible. With some attention to the filter and pickup position, BassDaWG/4 can sound similar to a fretless bass guitar.