EEEN462 -Vestigial-Sideband Amplitude Modulation (VSB-AM) Quiz

Test your knowledge of VSB-AM concepts and applications

Instructions: This quiz contains 10 multiple-choice questions about Vestigial-Sideband Amplitude Modulation. Select the best answer for each question. After completing all questions, click "Submit Quiz" to see your score and review the answers with explanations.

1 What is the primary advantage of VSB-AM over conventional AM?

A) Reduced bandwidth requirement compared to DSB-FC
B) Simpler demodulation circuit
C) Higher power efficiency
D) All of the above

2 In VSB-AM, what portion of the sideband is typically transmitted?

A) The entire upper sideband
B) The entire lower sideband
C) A vestige of one sideband and the entire other sideband
D) Only the carrier signal

3 The bandwidth of a VSB-AM signal is approximately:

A) Equal to the message bandwidth
B) Twice the message bandwidth
C) Slightly more than the message bandwidth
D) Half the message bandwidth

4 Which component is essential for proper demodulation of VSB-AM signals?

A) Phase-locked loop
B) Envelope detector
C) Balanced modulator
D) Frequency synthesizer

5 VSB-AM is commonly used in which application?

A) AM radio broadcasting
B) Television video transmission
C) Satellite communications
D) Digital data transmission

6 How does VSB-AM compare to SSB-SC in terms of implementation complexity?

A) VSB-AM is more complex to implement
B) SSB-SC is more complex to implement
C) They have similar complexity
D) Complexity depends on the application

7 The roll-off characteristics of the VSB filter determine:

A) The bandwidth efficiency
B) The power efficiency
C) The demodulation complexity
D) The carrier frequency

8 In VSB-AM, the transmitted power is primarily contained in:

A) The carrier
B) The sidebands
C) Equal distribution between carrier and sidebands
D) The vestigial portion only

9 What is the main reason VSB-AM is preferred over SSB for television transmission?

A) Better power efficiency
B) Simpler receiver design
C) Allows for DC component transmission
D) Reduced sensitivity to phase distortion

10 The VSB filter is designed to have what characteristic at the carrier frequency?

A) Maximum attenuation
B) 50% attenuation
C) Zero attenuation
D) Variable attenuation depending on modulation index

Quiz Results

Your Score: 0/10

Answer Key & Explanations

Question 1: What is the primary advantage of VSB-AM over conventional AM?

Correct Answer: D) All of the above

VSB-AM offers reduced bandwidth compared to DSB-FC (about 25% less), simpler demodulation using envelope detectors compared to synchronous detection, and improved power efficiency by partially suppressing one sideband.

Question 2: In VSB-AM, what portion of the sideband is typically transmitted?

Correct Answer: C) A vestige of one sideband and the entire other sideband

VSB-AM transmits one complete sideband and a vestige (portion) of the other sideband. This compromise between DSB and SSB allows for simpler filtering while maintaining good frequency response.

Question 3: The bandwidth of a VSB-AM signal is approximately:

Correct Answer: C) Slightly more than the message bandwidth

VSB-AM bandwidth is BW = f_m + f_v, where f_m is the message bandwidth and f_v is the vestigial bandwidth. This is slightly more than SSB (which is exactly f_m) but significantly less than DSB (which is 2f_m).

Question 4: Which component is essential for proper demodulation of VSB-AM signals?

Correct Answer: B) Envelope detector

Unlike SSB-SC which requires synchronous detection, VSB-AM can be demodulated using a simple envelope detector, making receiver design simpler and less expensive.

Question 5: VSB-AM is commonly used in which application?

Correct Answer: B) Television video transmission

VSB-AM is extensively used in analog television systems (like NTSC, PAL, SECAM) for video signal transmission because it provides a good compromise between bandwidth efficiency and receiver complexity.

Question 6: How does VSB-AM compare to SSB-SC in terms of implementation complexity?

Correct Answer: B) SSB-SC is more complex to implement

SSB-SC requires very sharp filters to completely remove one sideband, which are difficult and expensive to implement. VSB filters have more gradual roll-off characteristics, making them easier to design and manufacture.

Question 7: The roll-off characteristics of the VSB filter determine:

Correct Answer: A) The bandwidth efficiency

The roll-off characteristics of the VSB filter determine how much of the suppressed sideband is retained, which directly affects the total bandwidth of the transmitted signal and thus the bandwidth efficiency.

Question 8: In VSB-AM, the transmitted power is primarily contained in:

Correct Answer: A) The carrier

Like conventional AM, VSB-AM transmits the carrier at full power, which contains most of the transmitted power. The sidebands contain the information but contribute less to the total power.

Question 9: What is the main reason VSB-AM is preferred over SSB for television transmission?

Correct Answer: C) Allows for DC component transmission

Television signals contain significant low-frequency and DC components. SSB cannot transmit DC components effectively, while VSB-AM preserves low-frequency information better, making it suitable for video signals.

Question 10: The VSB filter is designed to have what characteristic at the carrier frequency?

Correct Answer: B) 50% attenuation

The VSB filter is specifically designed to have exactly 50% attenuation (6 dB loss) at the carrier frequency. This symmetrical attenuation characteristic ensures that the demodulated signal has minimal distortion.