If we use sine wave as input, how to control the input amplitude to accurately match the full scale?

I feel this is also important but hard. It is important because we need to calculate the probability function and back calculate the real histogram.

It is hard because if we set it too large and there is noise, the amplitude may saturate ADC dynamic range. And cause inaccuracy in calculated probability function.

Meanwhile, if we set it too low, it can't stress codes at both ends.

Any comments?