Except for the pluggable USB8Bit board, this is among the simplest DDS-type boards which can possibly be built: Basically, it's just an AVR RISC microcontroller connected to a DA converter.
Features:
8bit DA converter and fast R2R output buffer.
Up to 2MS/s (million samples per second).
Single 5V supply or USB-powered.
3 dedicated user-configurable IO ports (e.g. trigger input, sweep output, AD converter) and a diagnosis LED.
USB connection for waveform download via USB8Bit board.
8kb flash and 512 bytes SRAM, freely programmable 16MHz microcontroller.
USB-powered and externally powered operation.
http://www.triplespark.net/elec/oscillator/PoorManDDS/
