Assuming that even parity has been received as 001001. Assert if it is correct? If not find the correct code.


Q.) Assuming that even parity has been received as 001001. Assert if it is correct? If not find the correct code.

Subject: Digital Circuit and System Design

To determine if the received code with even parity is correct, we need to follow these steps:

Step 1: Understand Parity Bits

Parity bits are a simple form of error detection in digital communications. The even parity bit is set so that the total number of 1s in the code, including the parity bit itself, is even.

Step 2: Count the Number of 1s

Count the number of 1s in the received code excluding the parity bit. In this case, the received code is 001001, and we are not told which bit is the parity bit. We will assume the leftmost bit is the parity bit, as this is a common convention. If the parity bit is not at the leftmost position, the same process applies after identifying the correct position of the parity bit.

Step 3: Verify the Parity

Check if the count of 1s is even or odd. If it is even, then the parity is correct. If it is odd, then there is an error, and the parity is incorrect.

Step 4: Determine Correctness of the Received Code

Let's count the number of 1s in the received code 001001:

0 0 1 0 0 1

There are two 1s in the code.

Step 5: Assert if the Parity is Correct

Since we have an even number of 1s (which is 2), and we are using even parity, the parity is correct if the parity bit itself is 0. If the parity bit is 1, then the total count would be odd, and the parity would be incorrect.

Step 6: Conclusion

Given the received code 001001, we assume the first bit is the parity bit. The count of 1s excluding the parity bit is 2, which is even. Therefore, the parity bit should be 0 to maintain even parity.

Step 7: Correct Code (if necessary)

Since the parity is correct, there is no need to find a correct code. The received code 001001 is already correct.

Summary Table

Step Action Result
1 Understand parity bits Even parity means total 1s should be even
2 Count 1s in the code 2 1s
3 Verify parity Even number of 1s
4 Determine correctness Correct if parity bit is 0
5 Assert parity correctness Parity is correct
6 Conclusion Received code is correct
7 Correct code Not applicable (code is correct)

Example

Let's consider another example where the received code is 101001 with even parity:

1 0 1 0 0 1

Counting the 1s excluding the parity bit, we get 3 1s, which is odd. Therefore, the parity bit should be 1 to make the total count of 1s even. Since the parity bit is already 1, the received code 101001 is correct with respect to even parity.