Theory 

1. Excess-3 (XS-3) is a non-weighted code used in decimal systems.

2. It is derived from BCD (Binary-Coded Decimal) by adding 3 (0011₂) to each BCD digit.

3. Each decimal digit (0–9) is represented by a 4-bit code
   
   
   Conversion Rule (BCD → Excess-3)

1. Take the 4-bit BCD input.

2. Add 0011 (3 in binary).

3. Result = Excess-3 code.

Truth Table