28 Questions
What is the purpose of using multiplexers?
To merge multiple channels of information into a common medium
In the context of multiplexing, what does FDM stand for?
Frequency Division Multiplexing
How does FDM differ from TDM?
FDM uses frequency sharing, while TDM uses pulse techniques
Why is it necessary to let each channel modulate a separate subcarrier?
To eliminate overlapping signals in the frequency spectrum
What is the scheme for simultaneously transmitting multiple channels of intelligence called?
Multiplexing
At what stage does multiplexing occur in the transmission process?
Before the final modulation of the transmitted signal
What is the purpose of individually modulating subcarriers with an information source?
To allow for the transmission of multiple types of intelligence sources
What does frequency division multiplexing (FDM) achieve in terms of sharing frequency bands?
It allows channels to share the assigned frequency band without mutual interference
In a frequency division multiplexed system, how are the bandwidths of Channel 1 and Channel 2 related?
Channel 1's bandwidth ends before Channel 2's bandwidth begins
What is the main function of a multiplexer in the transmission process?
To simultaneously translate multiple channels into the radio frequency spectrum
What does a final modulating wave and a carrier wave produce?
A complex modulated wave
What technique is used to allow multiple channels to share the radio frequency spectrum without mutual interference?
Frequency Division Multiplexing (FDM)
What type of signals are contained in each channel in a frequency division multiplexed system?
Signals that are entirely contained by that channel
How are multiple multitone channels accommodated in a single VGC?
By combining their bandwidths to fit within the VGC's capacity
What happens in frequency translation in the context of multiplexing?
The multiplexer translates a number of channels into the radio frequency spectrum
What term is used to describe the modulation process applied to subcarriers in a frequency division multiplexed system?
Frequency Shift Keying (FSK)
What is the primary function of frequency-division multiplexing (FDM)?
Separating a given band of frequencies into individual channels
Which type of system transmits several channels of voice signals on one carrier in FDM?
Multichannel system
What does 'discrete' mean in the context of FDM?
The intelligence and the signal bearing the intelligence are separate, individual, and distinct entities
What frequency range is considered as 'quasistatic' in information rates in FDM?
0 to 10 Hz
What is the bandwidth requirement for intelligible speech in a voice grade channel (VGC) in FDM?
4000 Hz
What purpose do guardbands serve in FDM?
To keep signals from overlapping into other channels and causing interference
What is the primary difference between multichannel and multitone systems in FDM?
Multichannel systems transmit voice signals, while multitone systems transmit tone signals
What type of system is used exclusively to send information in a binary format in FDM?
Voice frequency tone system (VFTS)
In FDM, what does each channel modulate?
A subcarrier associated with that particular channel
What is the bandwidth requirement for individual channels within a multitone system in FDM?
3000 to 4000 Hz
What is the function of subcarriers in an FDM system?
To avoid overlapping by separating different channels
What frequency is Channel 3 assigned in an FDM system with 4 VGCs at intervals of 4 kHz?
20 kHz
Test your knowledge of multiplexers and subcarriers with this quiz. Learn about transmitting multiple channels of information into a common medium and the concept of separating information channels into different subcarrier assignments.
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