Agilent Technologies 93000 SOC Series Training Manual page 294

Lesson 1 – The Training ADC
NOTE
If ADCs are tested this way, many will pass, even with rather
different transfer curves. This is illustrated in the following figure,
where both ADCs return the same code:
Output of ADC #1
Output of ADC #2
Rudimentary ADC Testing
Only a truly continuous analog input (such as a ramp or sine
wave, for example) will let you discover the real transfer
characteristics of an ADC.
Because the DAC has a point map, DAC linearity tests can take
advantage of the fixed relationships between input and output.
Because the ADC has a one-way uncertainty, testing an ADC generally
requires more samples and more complex analysis than testing a DAC
of the same resolution.
The distortion parameters, however, (such as total harmonic
distortion, THD, or signal-to-noise ratio, SNR, etc.) can be
calculated the same way for DACs and ADCs.
294
V V V
1 2 3
V V V
1 2 3
Input voltage
Input voltage