Question: One way to detect single-bit errors when transmitting data is to attach a parity bit to the transferred data that indicates the number of 1s contained in the data. If the number of 1s in the received data does not agree with the parity bit, then the data was corrupted and an error output is produced. The circuit you designed in Problem 1.15 could be used as a parity bit generator. Design the parity bit checker circuit that receives the 4-bit data and the parity bit and detects single-bit errors by checking the total number of 1s in the data and the parity bit. Your circuit output (ERROR) should be 1 if the number of 1s in its 5-bit input is an even number and 0 if the number of 1s is an odd number.
Problem: Design a combinational circuit that outputs 1 if its 4-bit input contains an even number of 1s and 0 otherwise. Consider 0 an even number.