minimum step size of raw adc values

[rob_robinson]

Using a Picoscope 4823 and the python API I have measured and streamed some data of the voltage on a node (see attached for plot). The minimum step size between data points is approximately 19 (sometimes 18 or 20). Why is this the case?

My understanding is that the ADC has a 12 bit resolution.
The ps.ps4000aMaximumValue() return (2^15) -1.

To scale between the two ranges I could understand if the step size was 8 since 2^(15-12) but not why it is 19.

Are there some configuration settings that I am not aware of?

Cheers,
Rob

[bennog]

because 2^(16-12) is 16 and not 8 as you mentioned.

Ant the difference between 19 and 16 is because of calibration correction.

Benno