# Noise in communication system

Q16. Noise is added to a signal in a communication system

Options:

a) At the receiving end
b) At transmitting antenna
c) In the channel
d) During regeneration of the information

Correct Answer: c) In the channel

Explanation: Noise is an unwanted electrical signal that is added with the transmitted signal while passing through the communication channel. The noise interferes with the signal and may produce distortions to the signal.

Q17. Noise power at the resistor is affected by the value of the resistor as

Options:

a) Directly proportional to the value of the resistor
b) Inversely proportional to the value of the resistor
c) Unaffected by the value of the resistor
d) Becomes half as the resistance value is doubled

Correct Answer: c) Unaffected by the value of the resistor

Explanation :

The Noise power is given by
Pn= KTB
Where
K = 1.381×10-23 J/K, joules per Kelvin, the Boltzmann constant
B is the bandwidth at which the power Pn is delivered.
T noise temperature,
which is unaffected by change in the value of the resistor.