This project will describe how to make an AWG that can produce decent sine waves up to about 2Mhz, and of course all kinds of other waveforms, for around 20$ (assuming you own an stk500 or equivalent programmer).
This project assumes the builder is familiar with assembly language, atmel microcontrollers and their programmers, oscilloscope use, and basic electronics. All novel ideas and schematics are released under the GPL, all non-schematic images are released under a Creative Commons license.
2x 10 pF capacitors
1x crystal, preferably 16Mhz, I used 14Mhz
1x 5v voltage regulator
2x 9v battery
7x 50kohm resistors, 1%
10x 100kohm resistors, 1%
2x 4.7kohm resistors
1x 100kohm potentiometer
1x 10kohm potentiometer
1x OPA2132 op-amp, or any op-amp you're familiar with
2x 220uF electrolytic capacitors, rated 18v or higher
Finally, you will need the datasheets for the atmega16-16pu, and your opamp of choice. In the amplifier circuit, I labeled the pins by function and not by number, the datasheet will show you which pins are which (I used the same naming scheme as the datasheet).
The original html version of this project is available at http://legionlabs.nullnode.com/
The photo demonstrates a 1Mhz sine wave generated by the device.