This is related to one of my earlier posts on capturing a relatively pure sine wave (from a signal generator). I know the ADC limitation of the 8 bit AVR's of 200ksps/13 clock cycles as the ADC sampling frequency limiting the input sine frequency to about 6 kHz for all 10 bits. Are there any ways around this? How can I capture a 22kHz sine wave (not just peak or rms but a full sine wave)?
I was thinking of maybe splitting the sine wave into two waves with a phase shift of 90 degrees and then sampling the positive part in one half cycle and then switching to the 90 degrees phase shifted wave (Q wave) in the next and somehow stitching the two to get a full wave. Would this idea work? Any other ideas to make this possible using only the Atmega ADC?