AVR Direct Digital Synthesis
An AVR based R2R DDS with controls for offset and gain. Sine, sawtooth, square and triangle waveforms are stored in look up tables in the Atmega16?s internal flash. An LM358 is used to realize the offset and gain. The frequency range is 0 to 65534 Hz in 1 Hz steps. The enclosure is CNC cut from a CAD file.
1) Schematic 2) Board 3) Enclosure 4) 20kHz Sine wave after RC filter (below)