#mcs-042

Sketch the Manchester and differentiate Manchester encodings for the bit stream: 100111010101

Solution:

Question3. A bit stream 101010101101 transmitted using standard CRC method. The generator polynomial is x 4 +1. Show the actual bit string transmitted. Suppose the fourth bit from the left is inverted during transmission. Show that this error is detected at the receiver’s end.

Solution: Our generator G(x) = x4 + 1 encoded as 10101. Because the generator polynomial is of the degree three we append three zeros to the lower end of the frame to be transmitted. Hence after appending the 4 zeros the bit stream is 1010101011010000. On dividing the message by generator after appending three zeros to the frame we get a remainder of 0011. We do modulo 2 subtraction thereafter of the remainder from the bit stream with the three zeros appended. The actual frame transmitted is 1010101011010011. See below.