Data Acquisition System S/H ADC Transducer AMP Filter Analog MUX Transducer AMP Filter Digital Interface CPU DAC Translator AMP Filter Data Acquisition System

Amplifier Gain is adjusted to occupy the vange of ADC Dynamic range of the used signal = Pt is used to calculate the required no of bits “n” of ADC

Programmable gain Amplifier Vref R2 DAC R1 OR Vout - + Vo Vi

DAC - + R0 R1 R B0 B1 V out V ref

( ) R-2R Ladder Network 2 .... . ..... V B = + V ref - + B n-1 2 R V out R B n-2 2 R R 2 R R B 0 2 R ( ) 2 .... . ..... 1 fs ref n out V B = + - * For bipolar signal, use a summer circuit to add vfs/2 * For bipolar signal, use a summer circuit to add

Filter *LPF has to be used before sampling to give high attenuation at Fs/2 *Filter order is to be designed accordingly *Higher sampling may be used in intelligent applications ( eg. Speech synthesis and recognition) * Notch filter may be used at the mains frequency (50hz)

Typical filter for speech intelligent systems is shown Amplitude Frequency 50 100 8 k 10 k

Counter type ADC

Successive Approximation ADC