Communication Systems

In amplitude modulation, if a message signal of 5 kHz 2 is modulated by a carrier wave of frequency 900 kHz , then the frequencies of the side bands are

The heights of tansmitting and receiving antennas are respectively $\frac{1}{20000}$ and $\frac{1}{80000}$ times the radius of the
Earth. The maximum distance between these two antennas for satisfactory communication in line of sight mode i...

If the ratio of the maximum and minimum amplitudes of an amplitude modulated wave is $7: 3$, then the modulation index is

If the maximum and minimum amplitudes of a modulated wave are 25 V and 5 V respectively, then the modulation index is

Ionosphere acts as a reflector for the frequency range of

If in an amplitude modulated wave, the maximum amplitude is 14 V and the modulation index is 0.4 , then the amplitude of the carrier wave is

For transmitting a signal of frequency 1000 kHz , the minimum length of the antenna is

In amplitude modulation of waves, the maximum amplitude is 30 mV and minimum amplitude is 5 mV , then the modulation index is

If the sum of heights of transmitting and receiving antennas in line of sight of communication is ' $h$ ' then the height of receiving antenna, to have the range maximum is

The maximum distance between the transmitting and receiving antennas for satisfactory communication in line of sight mode is 57.6 km . If the height of the receiving antenna is 80 m , the height of the transmitting antenna is (radius of ear...

Which one of the following is not classified as pulse modulation?

An information signal of frequency 10 kHz is modulated with a carried wave of frequency $3.62 \mathrm{MHz}^{}$ The upper side and lower side frequencies are

A carrier is simultaneously modulated by two sine waves with modulation indices of 0.3 and 0.4 , then the total modulation index is

In amplitude modulation, the amplitude of the carrier wave is 10 V and the amplitude of one of the side bands is 2 V . Then, the modulation index is

If the maximum and minimum voltages of an $A M$ wave are $V_{\max }$ and $V_{\min }$ respectively. Then, the modulation factor $m$ is

A carrier wave of peak voltage 15 V is used to transmit a message signal. If the modulation index is $60 \%$, then the peak of voltage of the modulating signal is

Bandwidth of an optical fibre is