
88-16 Signal Processing
two-stage ADC built out of two ash ADCs and a fast DAC. e 6 bit ash ADC converts the residual
error of the 8 bit ash ADC. e two digital outputs are combined to produce a 12 bit conversion result.
If each ash ADC has a T/H at its input, then each stage can be converting the residual error from
the previous stage while the previous stage is converting the next sample. e whole converter then can
eectively operate at the sample rate of the slowest stage. Without the extra T/Hs, a new conversion can-
not
start until the residues have propagated through all the stages. is variation of the multistage ADC
is called a