Agilent Technologies Infiniium 8000A Programmer's Reference Manual page 860

Figure 30-2
Ideal ADC Conversion
111
110
101
100
011
010
001
000
Normalized Analog Input
ADC Non-linearity Errors for a 3-bit ADC
Waveform Commands
DATA? Example for Digital Channels
All ADCs have non-linearity errors which, if not corrected, can give less accurate
vertical measurement results. For example, the non-linearity error for a 3-bit
ADC is shown in the following figure.
The graph on the left shows an ADC which has no non-linearity errors. All of
the voltage levels are evenly spaced producing output codes that represent
evenly spaced voltages. In the graph on the right, the voltages are not evenly
spaced with some being wider and some being narrower than the others.
30-38
111
110
101
100
011
010
001
000
FS = the full scale
voltage of the ADC
Non-ideal ADC Conversion
Nonlinearity
Errors
Normalized Analog Input