JEE Main201911 Jan 2019Evening ShiftPhysicsCommunication SystemActual
An amplitude modulated signal is plotted below: Which one of the following best describes the above signal?
Options
- A(9+ (2.5 10⁵ t ) ) (2 10⁴ t ) V
- B(1+9 (2 10⁴ t ) ) (2.5 10⁵ t ) V
- C(9+ (2 10⁴ t ) ) (2.5 10⁵ t ) V
- D(9+ (4 10⁴ t ) ) (5 10⁵ t ) V
Correct answer
C. (9+ (2 10⁴ t ) ) (2.5 10⁵ t ) V
Step-by-step solution
After analysing the graph we may conclude that (i) Amplitude varies as 8-10 ~V or 9 1 (ii) Two time period as 100 s (signal wave) & 8 (carrier wave) So, equation of AM signal is [9 1 ( 2 t T₁ ) ( 2 t T₂ ) ]= [9 (2 10⁴ t ) ] (2.5 10⁵ t ) V