A carrier wave V _ C ( t ) = 160 (2π × 10 ^ 6 t) volts is made to vary between V _ = 200V and V _ = 120V by a message signal V _ m ( t ) = A _ m (2π × 10 ^ 3 t) volts. The peak voltage A _ m of the modulating signal is,

Correct answer: 40 Maximum amplitude, A _ = A _ m + A _ C ⇒ V _ = V _ m + V _ C 200 = V _ m + 160 V _ m = 40 ∴ Peak voltage A _ m = 40 Answer is 40 .

JEE Main 202120 JulyMorning Shift

JEE Main 2021 · 20 July · Morning Shift · Physics · Communication System

A carrier wave V _ C ( t ) = 160 (2π × 10 ^ 6 t) volts is made to...

A carrier wave

{V}_{C} ( t ) = 160\sin \left(2\pi \times {10}^{6}t\right)

volts is made to vary between

{V}_\max = 200V

and

{V}_\min = 120V

by a message signal

{V}_{m} ( t ) = {A}_{m}\sin \left(2\pi \times {10}^{3}t\right)

volts. The peak voltage

{A}_{m}

of the modulating signal is,

Maximum amplitude,

{A}_\max = {A}_{m} + {A}_{C}

⇒ {V}_\max = {V}_{m} + {V}_{C}

200 = {V}_{m} + 160

{V}_{m} = 40

∴

Peak voltage

{A}_{m} = 40

Answer is

40