Is it possible to do undersampling with the AD7760? I would prefer to sample a carrier in the range from 2MHz to 4MHz (fixed) with a bandwidth of 100kHz.
We haven't tried out any undersampling scenarios with AD7760 so I don't know what performance is achievable. The modulator can be set up so that it would undersample, just need to take care with a few things.
The diff-amp was designed for inputs up to 1MHz (as per AD7760 spec), so anything large signal in those 2 to 4MHz ranges, the datasheet specs would certainly not apply. There would have to be concerns about settling. Probably better to use external driver with specs for those types of input frequencies.
What is the magnitude of the signal to be measured, also if you give some indication to the application (can take to email if necessary) and the key performance specs - noise, acceptable distortion etc. We can do some sanity check and see if modulator would be ok.
I have attached a pdf page. Top diagram is the generic view with some definitions.
Bottom diagram would be settings that could undersample to the scenario you described. Again, you'd need to check out on EVB that the chain is capable at those input frequencies (and especially the magnitudes you need).
See what you think and advise on questions above.
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