What is the main advantage of single-sideband (SSB) over conventional AM for voice communication, and what additional requirement does SSB demodulation impose on the receiver?

What is the main advantage of single-sideband (SSB) over conventional AM for voice communication, and what additional requirement does SSB demodulation impose on the receiver?

• A. Easier generation; no extra requirement.
• B. Narrower bandwidth; requires carrier recovery or a pilot to reconstruct the suppressed carrier.
• C. Wider bandwidth; requires no additional processing.
• D. Same bandwidth; needs a second channel for demod.

Answer: (B)

The key idea is that SSB transmits only one sideband and suppresses the carrier, so the channel width needed for voice is basically the same as the original audio bandwidth, not double that as in conventional AM. This makes spectrum usage far more efficient and also reduces wasted transmitted power on the carrier. Because the carrier is removed, the receiver has to reinsert a carrier at the correct frequency and phase to recover the audio. This carrier reinsertion is done with a stable local oscillator (a beat-frequency oscillator) or a pilot reference to reconstruct the suppressed carrier before demodulation. If the carrier isn’t properly reinserted, the recovered audio won’t be accurate. So the best choice captures both points: narrower bandwidth and the need for carrier recovery or reinsertion at the receiver.

The key idea is that SSB transmits only one sideband and suppresses the carrier, so the channel width needed for voice is basically the same as the original audio bandwidth, not double that as in conventional AM. This makes spectrum usage far more efficient and also reduces wasted transmitted power on the carrier.

Because the carrier is removed, the receiver has to reinsert a carrier at the correct frequency and phase to recover the audio. This carrier reinsertion is done with a stable local oscillator (a beat-frequency oscillator) or a pilot reference to reconstruct the suppressed carrier before demodulation. If the carrier isn’t properly reinserted, the recovered audio won’t be accurate.

So the best choice captures both points: narrower bandwidth and the need for carrier recovery or reinsertion at the receiver.