Agilent Technologies 93000 SOC Series Training Manual page 582

Appendix B
A major factor is the ADC's inherent uncertainty.
Even an ideal ADC produces a quantization error which can be
seen as a sawtooth function.
Ideal ADC
Binary Output Code
111
110
101
100
011
010
001
000
1/4
1/8
Quantization Error
+1/2 LSB
–1/2 LSB
ADC Quantization Error
But other factors also reduce the available resolution:
Calculation of N
EFF
582
3/8
1/2 5/8 3/4 7/8 FS
Analog Input
Analog Input