$A$ carrier wave of peak voltage $60 \,V$ is used to transmit a message signal. Then the peak voltage of the modulating signal in order to have a modulation index of $90 \%$ is (in $\,V$)

What should be the height of the transmitting antenna and the population covered if the television telecast is to cover a radius of $150 \, km$? The average population density around the tower is $2000 \, / km^2$ and the value of $R_e = 6.5 \times 10^6 \, m$.

If the sum of the heights of transmitting and receiving antennas in the line of sight $(LOS)$ communication is fixed at $160 \, m$,then the maximum range of $LOS$ communication is $.... \, km$. (Take radius of Earth $R = 6400 \, km$)

$A$ message signal is used to modulate a carrier signal of frequency $5 MHz$ and peak voltage of $40 V$. In the process,two side-bands are produced separated by $40 kHz$. If the modulation index is $0.75$,then the peak voltage and frequency of the message signal,respectively,are:

The $...........$ is the link connecting the transmitter and the receiver.

Digital signal