Topic 5 - Majority vote

Question 1

What is the main difference between parity checking and majority voting?

Answer 1

The parity bit approach can only detect errors while majority voting can correct errors

Question 2

How does majority voting work?

Answer 2

Bits can change from 0 to 1 or from 1 to 0 during transmission because of interference.

So each bit is transmitted three times, so that if 1 bit accidentally changes then the device that receives the transmission can fix the error.

In your example, 000 has changed to 010. Since there are 2 zeros and 1 one then the program can use the rule of majority vote to assume that it should have been transmitted as 000.

Since the receiving device knows that 000 represents 0, it can reproduce the original signal

Question 3

What is checksum

Answer 3

A checksum is an error detection method where the number of bits transmitted in a message is counted; this checksum is compared with a count of the data received to check the integrity of the data transmission

Question 4

What are check digits?

Answer 4

A check digit is added to binary data to check that the data is accurate; this is an approach used by stores to check that the bar code printed on an item of shopping has been correctly inputted into the computer.