The maximum peak-to-peak voltage of an AM wave is 16 mV and the minimum peak-to-peak voltage is 4 mV.Calculate the modulation index.

3

(a)

For an optical communication system, operating at \(\lambda =800\ nm\), only 1% of the optical source frequency is the available channel bandwidth. How many channels can be accomdated for transmitting video T.V. signal requiring an approximate bandwidth of 4.5 MHz?

3

(a)

A ground receiver station is receiving a signal at 8 MHz, transmitted from a ground transmitter at a height of 289 m located at a distance of 100 km. Identify whether it is coming via space wave or sky wave propagation or satellite transponder. Radius of earth = 6.4 x 10⁶ m. Maximum number density of electrons in ionosphere = 10¹² m^-3.

3

(a)

If sky wave with a frequency of 60 MHz is incident on D-region at an angle of 30°, then find the angle of refraction.

3

(a)

What is meant by selectivity and sensitivity of radio receiver?

3

(a)