Recently, I studied about Folding & Interpolating ADCs. I didn't undrestand how they actually quantize the analog signal? can anybody give me a clear guidance about how it works, any example or good paper that would explain the exact operation of it? I do appreciate you.
F/I ADC work exactly like a flash. You have comparators and a resisitive string. You comparators have couple of stages of low gain preamps. One preamp/comparator generates one zero crossing (zx) at the referece value, because you look at Vin-Vref.
Now imagine you can actally compbine severeal preamps and generate more zx in one "folding amplifier", this reducing the number of comparators. You can also generate new zx by tapping in the middle of the existing zx with a resistive string (interpolation) reducing the number of preamplifiers.