NGF Waveshaper

Motivation

I kept all the waveforms of the original Elektor Formant, but changed the circuitry significantly. The only thing i added a symmetrical square out, that i found useful for sync. For converting the saw wave to triangle a precision full wave rectifier is used, followed by a level shifter. The originally used matched Germanium diodes are hard to obtain these days. Here you only have to match two resistors. The switching glitch is not audible and can be suppressed with means of a capacitor of some 100pF if wanted. Don't choose the capacitance to high, it rounds the edge of the triangle.

For triangle to sine conversion i used a well known circuit that works better then the two diodes approach from the original. This circuitry can be found at various places in Electronotes and others. The circuitry is very sensible to the used values and input voltage. If you use another input voltage you probably have to change type of FET and resistor values.

For wave shaping from saw to spaced saw I kept the original circuitry from the Elektor Formant. I only have to change some part values due to the different signal level.

New added is the saw to square waveshaper because I found it usefull to have a symmetrical square output.

The saw to pulse shaping is quite different to the original but quite standard.

Specs and features

• Regular input: Symmetric saw 10Vpp. Other input can make some interesting sounds as well.
• DC coupled
• Saw to triangle
• Triangle to sine
• Saw to square
• Saw to pulse
• Saw to spaced saw
• Schematic
• Pictures
• PSU +15V/-15V xxmA/xxmA

Disclaimer

All schematic, pictures, drafts, descriptions and other text at the site www.haraldswerk.de and in the associated blog are, if not otherwise mentioned, owned and copyrighted by Harald Antes. They are free for privat use only.

Impressum