Virtual Labs

DSB-SC, SSB-SC Modulator & Detector

How is the carrier signal used in the demodulation of a DSB-SC signal?

a: The carrier signal is needed at the receiver to recover the original message signal. Explanation

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b: The carrier signal is not needed for demodulation; only the modulated signal is required. Explanation

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c: The carrier signal is used to filter out the sidebands. Explanation

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d: The carrier signal is used to amplify the modulated signal. Explanation

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In Single Sideband Suppressed Carrier (SSB-SC) modulation, how is the message signal typically reconstructed?

a: By mixing the received signal with a local oscillator that has the same frequency as the carrier used in modulation. Explanation

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b: By filtering out the unwanted sideband from the received signal. Explanation

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c: By using an envelope detector to extract the message signal. Explanation

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d: By direct demodulation without any further processing. Explanation

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In DSB-SC modulation, why is carrier phase synchronization important at the receiver?

a: To ensure proper amplitude scaling of the message signal Explanation

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b: To correctly recover the message signal during coherent detection Explanation

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c: To eliminate noise from the received signal Explanation

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d: To increase bandwidth efficiency Explanation

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In SSB-SC demodulation, what combination of operations is required to recover the message signal?

a: Envelope detection only Explanation

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b: Band-pass filtering only Explanation

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c: Mixing with carrier followed by low-pass filtering Explanation

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d: High-pass filtering only Explanation

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In DSB-SC modulation, how is the amplitude of the carrier signal affected by the modulation process?

a: The amplitude of the carrier signal is suppressed or removed. Explanation

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b: The amplitude of the carrier signal increases proportionally with the message signal. Explanation

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c: The amplitude of the carrier signal remains unchanged. Explanation

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d: The amplitude of the carrier signal is modulated in a manner similar to amplitude modulation. Explanation

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What is the key difference between DSB-SC and SSB-SC in terms of bandwidth usage?

a: DSB-SC uses twice the bandwidth of SSB-SC. Explanation

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b: SSB-SC uses twice the bandwidth of DSB-SC. Explanation

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c: DSB-SC and SSB-SC use the same bandwidth. Explanation

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d: Bandwidth usage depends on the modulation index of the signal. Explanation

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In an SSB-SC signal, what happens to the carrier frequency?

a: The carrier frequency is completely removed from the signal. Explanation

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b: The carrier frequency is present but at a reduced amplitude. Explanation

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c: The carrier frequency is modulated along with the message signal. Explanation

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d: The carrier frequency is used for phase modulation of the message signal. Explanation

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What is the total bandwidth required to transmit a DSB-SC signal if the message signal has a maximum frequency of f_m?

a: f_m Explanation

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b: 2 f_m Explanation

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c: 4 f_m Explanation

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d: f_m / 2 Explanation

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Which of the following best explains why SSB-SC is preferred over DSB-SC in long-distance communication systems?

a: It uses less bandwidth and avoids transmitting redundant sideband power Explanation

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b: It eliminates the need for coherent detection Explanation

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c: It increases the carrier power for better transmission Explanation

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d: It simplifies receiver design significantly Explanation

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In a communication system using DSB-SC, what is the main reason a coherent detector is preferred over an envelope detector?

a: Coherent detection accurately recovers the message signal even when the carrier is suppressed. Explanation

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b: Envelope detection is faster than coherent detection. Explanation

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c: Coherent detection requires less power than envelope detection. Explanation

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d: Envelope detection can recover SSB-SC signals reliably. Explanation

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