Question

Design a truth table for a combinational circuit that detects an error in the representation of a decimal digit encoded in BCD (this circuit should output a 1 when the input is one of the six unused combinations for BCD code).

Answer 1

To detect an error in the representation of a decimal digit encoded in BCD, we need to create a truth table for a combinational circuit. The circuit should output a 1 for the six unused combinations in BCD code: 1010, 1011, 1100, 1101, 1110, and 1111.

Step-by-step explanation:

To design a truth table for a combinational circuit that detects an error in the representation of a decimal digit encoded in BCD, we need to identify the six unused combinations in the BCD code. The BCD code represents decimal digits using the four-bit binary code, ranging from 0000 to 1001. The six unused combinations are 1010, 1011, 1100, 1101, 1110, and 1111.

In the truth table, the circuit should output a 1 for the unused combinations. For example, if the input is 1010 (which is not a valid BCD digit), the output should be 1. For all other inputs in the valid range, the output should be 0.

The truth table would look like this:

InputOutput00000000100010000110010000101001100011101000010010101011011111001110111110111111