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To increase the ADC resolution, oversampling technique can be used which must be followed by decimation (average) method.
Oversampling is just take several samples within time period. Unlike the normal averaging in which you might lose all the extra bits from oversampling, Decimation can remove only the lowest of low bits leaving some of the higher low bit to contribute to final result.
What is the lowest and higher low bit? And why the lowest low bit usually most noisy than the rest of the bits?
From my understanding is that the higher the extra bit can we get, a better ADC resolution can we have. In this case why can't we just use oversampling without decimation?
For example, a summation of 16 10-bit ADC result in 14-bit ADC and when we use decimation method (divide by 4) result in 12-bit resolution.
So why can't we just use oversampling and gain 14-bit resolution instead of 12-bit resolution with decimation?
Is that to reduce the noise after the oversampling stage?