# Excess-3 Code

What is a BCD? What are its advantages and disadvantages? Why is an excess-3 code is called an unweighted code?

#### gurulakshmi05 Profile Answers by gurulakshmi05

• Jul 1st, 2009

BCD means Binary coded decimal, its advantage is it can represent decimal numbers in the form of binary value says (0000-0 to 1001-9).

Binary codes are divided into weighted binary code and non weighted binary code,
Excess 3 code is an example of non weighted codes since the position of each bits in excess 3 code does not have weights says like ones, tens, hundred in decimal and 2^0,2^1,2^2, in binary.

#### Namita Chhantyal

• Dec 13th, 2017

BCD is a binary coded decimal that can represent each decimal digits into it’s respective 4 binary bit.

The advantage is that it is easy to convert into BCD code from decimal digit and vice-versa.

Disadvantage - It requires a complex design of ALU for performing arithmetic operations.

XS-3 code is called weighted code because it doesn’t follow the principle of position of weighting i.e the each number is not given a specific weight.  