Precision of ADC

Question: How can the ADC in PSoC (Power Meter), which is only 8-bit incremental, reach the same precision as the ADC in ADE7755, which is 16-bit delta-sigma?



 There are two reasons why we can use an 8-bit ADC instead of a 16-bit. First, our algorithm accumulates 64 samples of the current and voltage waveform, effectively adding 2.5 bits of resolution. Secondly, we dynamically adjust the gain of the input amplifier such that the peak-to-peak values of the current and voltage waveform span at least 100 ADC counts. These two factors allow us to obtain an accuracy of greater than 1% over the range of the meter.