The transmission loss per kilometer in an optical fiber is approximately...........$dB$.

What is an analog signal?

An antenna is mounted on a $400 \; m$ tall building. What will be the wavelength of the signal that can be radiated effectively by the transmission tower up to a range of $44 \; km$? (In $m$)

In a communication system,the process of superimposing a low-frequency signal on a high-frequency wave is known as:

$A$ $..........$ is used in the receiver section to reduce the magnitude of signals.

$A$ carrier wave $v_{c}(t) = 160 \sin(2 \pi \times 10^{6} t) \text{ V}$ is made to vary between $V_{\max} = 200 \text{ V}$ and $V_{\min} = 120 \text{ V}$ by a message signal $v_{m}(t) = A_{m} \sin(2 \pi \times 10^{3} t) \text{ V}$. The peak voltage $A_{m}$ of the modulating signal is ..... .