$A$ wave is represented as $e = 10\,(1 + 6\, \sin(50t)) \sin(10^8t)$. The modulation index is:

Consider the following statements regarding satellite communication:
$1$. Frequencies between $1.5 \text{ MHz}$ and $1 \text{ MHz}$ are used in satellite communication.
$2$. The frequencies for uplink and downlink are different.
$3$. The orbit of a geostationary satellite makes an angle of $0^{\circ}$ with the equatorial plane of the Earth.
Which of the above statements are correct?

For the output of an $AM$ detector circuit to follow the envelope of the carrier wave,which condition must be satisfied? ($T_c$ is the time period of the carrier wave.)

$A$ message signal of frequency $14 kHz$ is used to modulate a carrier of frequency $900 kHz$. The frequencies of the sidebands are:

The circuit used to separate information signals from the carrier wave is called a .......

What is the advantage of an optical fibre?