3-bit AD converter circuit structure

Shown is the circuit structure of a 3-bit parallel A/D converter . The analog signal is sent to the input terminal of the A/D converter , which is simultaneously added to the interphase input terminals of seven voltage comparators . The reverse input terminals of the seven voltage comparators are connected to the reference voltages of the comparators, and the seven reference voltages are respectively connected to series resistor dividers, which is equivalent to dividing the signal amplitude into seven levels (I/7 Vo—7 /7 Vo). If the input signal is less than 1/7 Vo, all voltage comparator outputs are 0. After passing through the latch and encoder, the total output is 000. If the input signal amplitude is greater than 2/7 Vo and less than 3/7 Vo, the voltage comparators Wl and W2 will output 1, and the encoder will output 010. The true values ​​of the A/ D converter are shown in Table 21-1.