Is the diagram in the application note incorrect? Pins 19 and 20 appear to be floating? Also, the output waveform is the same frequency as the input waveform. Shouldn't this modulated waveform be twice the frequency of the input waveform?
I'm trying to measure a low level signal from a photodetector. The input to the ad630 is a large (almost rail to rail), very noisy signal and I'm trying to recover the original signal.