NCERT Solutions for Chapter: Communication Systems, Exercise 4: LA

An amplitude-modulated wave is as shown in the figure. Calculate the peak value of information voltage.

Draw the plot of amplitude versus $‘\mathrm{\omega }’$ for an amplitude modulated wave whose carrier wave $\left({\mathrm{\omega }}_{\mathrm{c}}\right)$ is carrying two modulating signals, ${\mathrm{\omega }}_{m_1}$ and${\mathrm{\omega }}_{{\mathrm{m}}_2} ({\mathrm{\omega }}_{{\mathrm{m}}_2} > {\mathrm{\omega }}_{{\mathrm{m}}_1})$.

Draw the plot of amplitude versus ‘ω’ for an amplitude modulated wave whose carrier wave $\left({\mathrm{\omega }}_{\mathrm{c}}\right)$. Is the plot symmetrical about ${\mathrm{\omega }}_{\mathrm{c}}$? Comment especially about the plot in region $\mathrm{\omega }<{\mathrm{\omega }}_{\mathrm{c}}$.

Draw the plot of amplitude versus ‘ω’ for an amplitude modulated wave whose carrier wave $\left({\mathrm{\omega }}_{\mathrm{c}}\right)$ extrapolate and predict the problems one can expect if more waves are to be modulated.

Draw the plot of amplitude versus ‘ω’ for an amplitude modulated wave whose carrier wave $\left({\mathrm{\omega }}_{\mathrm{c}}\right)$ Suggest solutions to the above problem. In the process can one understand another advantage of modulation in terms of bandwidth?

An audio signal is modulated by a carrier wave of $20 \mathrm{MHz}$ such that the bandwidth required for modulation is $3 \mathrm{kHz}$. Could this wave be demodulated by a diode detector that has the values of $\mathrm{R}$ and $\mathrm{C}$ as $\mathrm{R}=1 \mathrm{k}\Omega , \mathrm{C}=0.01\mathrm{\mu F}.$

An audio signal is modulated by a carrier wave of $20 \mathrm{MHz}$ such that the bandwidth required for modulation is $3 \mathrm{kHz}$. Could thiswave be demodulated by a diode detector which has the valuesof $\mathrm{R}$ and $\mathrm{C}$ as $\mathrm{R}=10 \mathrm{k}\Omega , \mathrm{C}=0.01\mathrm{\mu F}$.

An audio signal is modulated by a carrier wave of $20 \mathrm{MHz}$ such that the bandwidth required for modulation is $3 \mathrm{kHz}$. Could this wave be demodulated by a diode detector which has the values of $\mathrm{R}$ and $\mathrm{C}$ as $\mathrm{R} = 10 \mathrm{k}\Omega , \mathrm{C} = 0.1\mathrm{\mu F}$.