A signal with bandwidth 20 kHz is being transmitted using amplitude modulation. To prevent overlapping of sidebands and allow for efficient filtering at the receiver, what is the minimum required carrier frequency?

Television signals reach us only through the ground waves. The range $R$ related with the transmitter height $h$ is in Proportional to

The density of air at the top of mesosphere in comparison to that of near the earth’s surface is

What is ozone hole

What is the value of frequency at which electromagnetic wave must be propagated for the D-region of atmosphere to have a refractive index of 0.5. Electron density for D-region is 400 electrons/cc

A TV tower has a height 150 m. What is the total population covered by the TV tower, if the population density around the TV tower is ${10^3}{\rm{\;k}}{{\rm{m}}^{ - 2}}?$ Radius of the earth is $6.4 imes {10^6}\;{\rm{m}}.$

To cover a population of 20 lakh, a transmission tower should have a height … (Radius of earth = 6400 km, population per square km =1000)

Basically, a communication system is a

The output stage of a television transmitter is most likely to be a

The relation between the maximum electron density ${N_{{\rm{max}}}}$ and the critical frequency ${f_c}$ for the ionosphere can be given as

A sky wave with a frequency 55 MHz is incident on the D-region of earth's atmosphere at30°. The angle of refraction is (electron density for D-region is 400 electron/cc)