Carrying over discussion from the end of this thread. I would like to get some input and help in designing, prototyping and completing a DIY function generator. I guess there are two ways to approach it: Standard function generator chip eg. XR2206 DDS (Direct Digital Synthesis) chip eg. AD9850 The XR2206 approach is much easier, can perform all the functions itself and has minimal extra components. However it is not as accurate and lower speed (0.01Hz - 1MHz) The DDS approach will be much more involved, as we'll need some type of microcontroller to set the frequency and output. However it is incredibly accurate and can go into the 10's and 100's of MHz. Having the parts easily available the larger electronics sites would be a plus. As well as easier to solder chips (down to SMD SSOP for example). Oh, and all the parts obtainable for <$50 would be good. Then perhaps when the design is finalised we can get some professional PCB's made up for kit sales etc.