(a) Give three different ways how electro-magnetic interference can be reduced in twisted pairs based transmission.
(b) Noise are unwanted signals affecting transmission. List four different types of noise.
(c) Optical fibre and satellite microwave are both examples of transmission media.
(i) Compare these two transmission media by making reference to characteristics namely bandwidth, immunity to interference, security, multipoint capability, flexibility and connectivity to customer site.
(ii) Explain why the optical signals used in fibre optic have a very short wave length.
(iii) Why lasers and single mode fibre, though more expensive, are sometimes used to send light over a fibre link?
(d) In a single-bit even parity check scheme, the transmitter sends the byte 10010101 and because of channel noise, the receiver gets 10100101. The receiver will assume that the received byte is free of errors. Explain the reasoning behind such a decoding rule?
(e) Suppose that the following message 1010011110 is transmitted and we are using the standard CRC for error detection. Assume that the generator polynomial is x3 + x + 1. What is the actual bit stream transmitted?