What does DSB stand for in communication systems?
Analysis & Theory
DSB stands for Double Sideband, where both sidebands of an AM signal are transmitted.
What is the main limitation of DSB in AM transmission?
B
High bandwidth and power wastage
Analysis & Theory
DSB transmits both sidebands and the carrier, leading to inefficient use of bandwidth and power.
In DSB-SC (suppressed carrier), which components are transmitted?
C
Carrier and one sideband
D
Carrier and both sidebands
Analysis & Theory
DSB-SC suppresses the carrier and transmits only the upper and lower sidebands.
What is the main advantage of VSB over DSB?
C
Reduced bandwidth while retaining signal integrity
Analysis & Theory
VSB transmits one full sideband and a partial (vestige) of the other, conserving bandwidth and preserving key signal information.
VSB is commonly used in which application?
Analysis & Theory
VSB is used in analog television for video signal transmission to reduce bandwidth while preserving quality.
What does the ‘vestigial’ part in VSB refer to?
B
A reduced or partial sideband
Analysis & Theory
‘Vestigial’ refers to the partial transmission of one of the sidebands.
In VSB transmission, why is part of one sideband retained?
B
To aid in signal recovery
D
To transmit in higher frequency bands
Analysis & Theory
The vestigial sideband helps in easier demodulation and reconstructs the signal properly.
What is the bandwidth requirement for DSB-SC if the message bandwidth is 5 kHz?
Analysis & Theory
DSB-SC requires double the message bandwidth: 2 × 5 kHz = 10 kHz.
What filtering technique is commonly used in VSB transmission?
Analysis & Theory
A Nyquist filter is used to shape the spectrum and allow partial sideband transmission in VSB.
Which of the following best describes DSB-SC modulation?
A
Both sidebands transmitted without the carrier
B
Only one sideband and carrier transmitted
C
Carrier and both sidebands transmitted
D
Only carrier transmitted
Analysis & Theory
DSB-SC transmits both sidebands but suppresses the carrier, making it more power-efficient.