1. Which are the common transmission media used in digital communication system?
a) Coaxial cable
b) Twisted copper cable
c) Radio frequency bands
d) All of the mentioned
Explanation: Some of the commonly used physical transmission media are twisted copper cable, good quality coaxial cable and radio frequency bands.
2. The basic transmission-reception system is a ______ system.
a) Two block system
b) Three block system
c) Four block system
d) None of the mentioned
Explanation: The basic transmission-reception consists of three blocks – transmitter, transmission medium, receiver.
3. Modulation channel consists of
a) Amplifier
b) Signal processing units
c) Amplifier & Signal processing units
d) None of the mentioned
Explanation: When information is transmitted through large distance it must be amplified. Modulation channel consists of an amplifier and other signal processing units
4. Modulation channel does not accept an analog input signal.
a) True
b) False
Explanation: Modulation channel accepts analog signal as input and delivers another version of modulated signal as analog waveform.
5. If operating frequency bands are higher ______ is available.
a) Smaller bandwidth
b) Larger bandwidth
c) Smaller & Larger bandwidth
d) Cannot be determined
Explanation: Larger bandwidth is available when operating frequency bands are higher.
6. Ground wave communication occurs in
a) Low frequency band
b) Medium frequency band
c) Low & Medium frequency band
d) None of the mentioned
Explanation: Ground wave communication can take place in both low frequency and medium frequency bands
7. Sampling theorem is used for converting
a) Continuous time signal to discrete
b) Discrete to continuous time signal
c) Continuous time signal to discrete & vice versa
d) None of the mentioned
Explanation: Sampling theorem is used for converting continuous time signal to discrete type signal and vice versa
8. A signal can be recovered from its sample by using
a) Low pass filter
b) High pass filter
c) Band pass filter
d) Band stop filter
Explanation: A signal can be recovered from its sampled version by using an ideal low pass filter.
9. Which is practically realizable?
a) A train of pulses
b) Impulse train
c) All of the mentioned
d) None of the mentioned
Explanation: A train of pulses with narrow bandwidth is realizable than the impulse train
10. In flat top sampling scheme, ______ is kept constant after sampling.
a) Amplitude
b) Phase
c) Frequency
d) Time period
Explanation: In flat top sampling scheme, the amplitude is kept constant after sampling