1. Multiplexing is the process of:
(A) Combining multiple signals for transmission over a single channel
(B) Separating signals from noise
(C) Amplifying the message signal
(D) Detecting a modulated signal
2. The main purpose of multiplexing is to:
(A) Use a communication channel efficiently
(B) Reduce signal power
(C) Increase signal frequency
(D) Amplify the transmitted signal
3. The types of multiplexing are:
(A) FDM, TDM, and WDM
(B) AM, FM, and PM
(C) PAM, PWM, and PPM
(D) ASK, FSK, and PSK
4. FDM stands for:
(A) Frequency Division Multiplexing
(B) Frequency Distribution Method
(C) Fast Digital Multiplexing
(D) Frequency Data Management
5. TDM stands for:
(A) Time Division Multiplexing
(B) Transmission Data Modulation
(C) Time Delay Method
(D) Time Detection Mechanism
6. WDM stands for:
(A) Wavelength Division Multiplexing
(B) Wide Data Management
(C) Wireless Digital Multiplexing
(D) Wave Detection Modulation
7. In FDM, each signal is assigned a unique:
(A) Frequency band
(B) Time slot
(C) Amplitude level
(D) Phase shift
8. In TDM, each signal is assigned a unique:
(A) Time slot
(B) Frequency band
(C) Amplitude
(D) Wavelength
9. WDM is used mainly in:
(A) Optical fiber communication
(B) Radio transmission
(C) AM broadcasting
(D) Telephone systems
10. The main advantage of multiplexing is:
(A) Efficient utilization of bandwidth
(B) Increased noise
(C) Reduced signal range
(D) Complex hardware
11. The process of extracting the original message from a modulated signal is called:
(A) Demodulation
(B) Multiplexing
(C) Sampling
(D) Encoding
12. The device used for demodulation is called a:
(A) Demodulator
(B) Modulator
(C) Multiplexer
(D) Amplifier
13. Demodulation is performed at the:
(A) Receiver
(B) Transmitter
(C) Channel
(D) Antenna
14. In AM systems, demodulation is usually performed by:
(A) Envelope detector
(B) Frequency discriminator
(C) Phase detector
(D) Mixer
15. In FM systems, demodulation is performed by:
(A) Frequency discriminator or PLL
(B) Envelope detector
(C) Rectifier
(D) Peak detector
16. In TDM, signals share the same frequency but:
(A) Transmit at different times
(B) Use different amplitude levels
(C) Use different channels
(D) Vary in phase
17. In FDM, signals share the same time but:
(A) Use different frequency bands
(B) Use different time slots
(C) Have identical frequencies
(D) Are time-delayed
18. Guard bands in FDM are used to:
(A) Prevent overlapping between adjacent channels
(B) Increase transmission power
(C) Enhance signal speed
(D) Reduce amplitude variations
19. In TDM, synchronization between transmitter and receiver is:
(A) Very important
(B) Not required
(C) Optional
(D) Automatically maintained
20. WDM allows multiple signals by varying:
(A) The wavelength of light
(B) The time slot
(C) The frequency band
(D) The amplitude
21. Multiplexers are used at the:
(A) Transmitting end
(B) Receiving end
(C) Both ends
(D) Channel only
22. Demultiplexers are used at the:
(A) Receiving end
(B) Transmitting end
(C) Channel
(D) Both ends
23. The main disadvantage of FDM is:
(A) Requires large bandwidth
(B) Difficult to synchronize
(C) High noise sensitivity
(D) Low efficiency
24. The main disadvantage of TDM is:
(A) Requires synchronization between transmitter and receiver
(B) Needs guard bands
(C) Low efficiency
(D) High distortion
25. In digital communication, TDM is more commonly used because:
(A) It handles digital signals efficiently
(B) It reduces noise completely
(C) It does not require synchronization
(D) It uses analog signals
26. The function of a demodulator in a receiver is to:
(A) Recover the baseband signal
(B) Increase carrier frequency
(C) Amplify the modulated signal
(D) Filter out noise only
27. In FM demodulation, the output of a discriminator corresponds to:
(A) Instantaneous frequency variations
(B) Amplitude variations
(C) Phase variations
(D) Time delay
28. The main purpose of a demultiplexer is to:
(A) Separate multiple signals combined during multiplexing
(B) Combine signals into one channel
(C) Increase bandwidth
(D) Detect noise
29. The overall benefit of multiplexing in communication systems is:
(A) Increased channel efficiency and capacity
(B) Reduced channel bandwidth
(C) Lower transmission speed
(D) Simplified transmission
30. The process that is the reverse of multiplexing is called:
(A) Demultiplexing
(B) Modulation
(C) Sampling
(D) Encoding