This circuit is a 4-bit fault detector that compares the transmitted message (T) with the received message (R) to identify mismatched bit positions. XOR gates are used to compare each corresponding pair of bits. The circuit then determines the total number of errors and activates the appropriate LED: LED 1 for no errors, LED 2 for an odd number of errors, and LED 3 when all four bits are mismatched. This circuit demonstrates the use of combinational logic gates for error detection in digital communication systems.
