Modulation and Demodulation

The diagram given below shows the block diagram of a detector for AM signals.


Label the unlabelled boxes in this block diagram indicated by (b) and (c).

Which of the following factors justify the need of modulating a signal:

Among following, the factor which justifies the need of modulating a signal is

How does the effective power radiated by an antenna (of length l) vary with wavelength?

A FM Broad cast transmitter, using modulating signal of frequency $20 \mathrm{kHz}$has a deviation ratio of $10$. The Bandwidth required for transmission is:

The amplitude of $15 \sin (1000 \pi t)$ is modulated by $10 \sin (4 \pi t)$ signal. The amplitude modulated signal contains frequencies of

A. $500 \mathrm{Hz}$

B. $2 \mathrm{Hz}$

C. $250 \mathrm{Hz}$

D. $498 \mathrm{Hz}$

E. $502 \mathrm{Hz}$

Choose the correct answer from the options given below

A carrier wave of amplitude $15 \mathrm{V}$ is modulated by a sinusoidal base band signal of amplitude $3 \mathrm{V}$. The ratio of maximum amplitude to minimum amplitude in an amplitude modulated wave is

For an amplitude modulated wave the minimum amplitude is $3 \mathrm{V}$, while the modulation index is $60\%$. The maximum amplitude of the modulated wave is:

In amplitude modulation with carrier frequency $\left(A_c\right)$ and modulating frequency $\left(A_m\right)$, modulation index is $60\%$. If $A_c- A_m= 3 \mathrm{V}$, then $A_c+A_m$ is equal to

A signal of square shape is superimposed with a carrier wave$y_c=2\sin ({\omega }_{c}t-kx)$, then modulation index of amplitude modulated wave is

The modulation index for an A.M. wave having maximum and minimum peak to peak voltages of $14 \mathrm{mV}$ and $6 \mathrm{mV}$ respectively is :

A message signal of frequency $15 \mathrm{kHz}$ is used to modulate a carrier of frequency $v_c$. If the side bands produced are $1515 \mathrm{kHz}$ and $1485 \mathrm{kHz}$, then $v_c$ is

The maximum peak to peak voltage of an $\mathrm{AM}$-wave is $18 \mathrm{V}$ and the minimum peak to peak voltage is $6 \mathrm{V}$ of the same wave. What is the modulation factor of the wave?

A carrier wave is used to transmit a message signal. If the peak voltage of modulating signal and carrier signal are increased by $1\%$ and $3\%$ respectively, the modulation index is changed by

An amplitude modulated signal is plotted below:

The maximum frequency of an amplitude modulated wave is $850\mathrm{Hz}$ and its bandwidth is $50\mathrm{Hz}$. The carrier frequency of the wave is

It is desired to transmit an electronic signal in the Audio Frequency (AF) range. Which of the following statements on amplitude modulation of the signal by a carrier wave is NOT TRUE?

A modulating signal $m\left(t\right)$ has an amplitude of $10 \mathrm{V}$ and a frequency of $1 \mathrm{kHz}.$ The amplitude is modulated by a carrier signal with a frequency of $100 \mathrm{kHz}.$ If the modulation index is $0.2,$ the carrier signal $c\left(t\right)$ is given by

Find the modulation factor if maximum peak to peak voltage of an $AM$ wire is $24 \mathrm{mV}$ and the minimum peak to peak voltage is $8 \mathrm{mV}$.

What is the modulating index of an oscillator which is producing FM waves of frequency $2 \text{kHz}$ with a variation of $10 \mathrm{kHz}$?