So, I'm working on a project right now to implement a large electrode sensor array for measuring bio-potential (128 x 128 sensors) that are in close proximity to each other (~0.06cm along horizontal and vertical). The signals themselves are relatively small, being on the order of tens to hundreds of micro Volts.
I want to select an arbitrary 64 sensor subset of these signals and route them to an amplifier circuit and then to an ADC circuit sampled at 250Hz (each selected signal has its own respective amplifier/adc path. Thus 64 amps and 64 ADCs, one of each for each selected signal). The configuration of selected signals only changes once every half minute or so, thus switching speed is not of paramount importance.
That said, I'm not sure how to go about selecting the signals to use properly. It doesn't seem practical to directly select 1 signal from over ~16,000 possible sources by having an enormous number of inputs to a multiplexer(s). I imagine (and vaguely remember reading some approaches like this) I could leverage the grid pattern to select from the analog inputs without massive amounts of logic, but I'm not entirely sure how I could go about doing that.
I would supply some datasheets to help out, but I'm still looking at this from a very top-down angle in order to get it conceptually straight in my head before hammering out specific components and such.
Thanks in advance for any help you can provide.