List of top Physics Questions on communication systems asked in KEAM

Line-of-sight communication happens by means of :

In communication systems, the device used to convert energy from one form to another form is

The range of frequency bands used for television $VHF$ service is

Modulation is the process of superposing

Identify the mismatched pair

A ground receiver in line-of-sight communication cannot receive direct waves due to

A ground receiver receives a signal at $5\, MHz$, transmitted by a ground transmitter at a height of $320\, m$, which is $110\, km$ away from it. Then it can communicate through (radius of earth $R \,= \,6400 \,km$)

For signal transmission, modulation is necessary

If $ {{E}_{c}}=20\,\,\sin \,{{10}^{5}}\,\pi t $ and $ {{E}_{m}}=10\sin 400\pi t $ it are carrier and modulating signals, the modulation index is

If the critical frequency for sky wave propagation is 12 MHz, then the maximum electron density in the ionosphere is

In an amplitude modulation with modulation index $0.5$, the ratio of the amplitude of the carrier wave to that of the side band in the modulated wave is

In amplitude modulation, the bandwidth is

The mobile telephones operate typically in the range of

The area of the region covered by the TV broadcast by a TV tower of 100 m height is (Radius of the earth = $ 6.4 \times 10^6 \, m $ )

In the amplitude modulation mode of transmission, the normal speed signal is with a maximum frequency of $5\, kHz$. If the carrier frequency is $200\, kHz$, the modulated signal will have the frequencies varying between

Audio signal cannot be transmitted because

In frequency modulation