Question

In amplitude modulation:
(A) The envelope detector operates properly, only if $(1/f_c) \leq RC \leq (1/f_m)$
(B) Vestigial sideband modulation is used in television broadcasting.
(C) Selective fading produces more distortion in SSB-SC systems than in DSB-SC.
(D) Efficiency of a suppressed carrier system is 100%, whereas in AM the maximum efficiency is only 33.3%.
Choose the correct answer from the options given below:

• A. (A), (B) and (D) only
• B. (B) and (C) only
• C. (A), (C) and (D) only
• D. (B), (C) and (D) only

Hint:

For AM systems, remember efficiency limits and where each modulation scheme is practically used.

Answer 1

The Correct Option is D

Step 1: Review AM characteristics.
- Envelope detection is an approximation.
- VSB is used for TV transmission.
- SSB-SC is more susceptible to selective fading.
- AM's maximum efficiency is 33.3%.

Step 2: Identify the correct statements.
Options (B), (C), and (D) are correct.
Final Answer: \[\boxed{(4)}\]