Q#1: Data can be classified into:
(A) Analog only
(B) Digital only
(C) Digital and Analog
(D) None of the above
Answer: (C) Digital and Analog
Q#2: Which of the following is an analog signal?
(A) Text file
(B) Voice from a microphone
(C) Binary data
(D) Digitized image
Answer: (B) Voice from a microphone
Q#3: Which of the following is a digital signal?
(A) Audio waveform
(B) Video broadcast
(C) Binary data
(D) Radio wave
Answer: (C) Binary data
Q#4: The amplitude of a signal represents:
(A) Number of cycles per second
(B) Signal strength
(C) Phase shift
(D) None of the above
Answer: (B) Signal strength
Q#5: The frequency of a signal represents:
(A) Number of cycles per second
(B) Signal strength
(C) Phase
(D) Bit rate
Answer: (A) Number of cycles per second
Q#6: The phase of a signal refers to:
(A) Amplitude of the signal
(B) Timing position of the wave
(C) Frequency of the signal
(D) Bit rate
Answer: (B) Timing position of the wave
Q#7: Periodic signals repeat after:
(A) Every second
(B) A fixed time period
(C) Every bit
(D) Every frequency
Answer: (B) A fixed time period
Q#8: Aperiodic signals:
(A) Repeat periodically
(B) Do not repeat regularly
(C) Are always analog
(D) Are always digital
Answer: (B) Do not repeat regularly
Q#9: Baseband signals use:
(A) Single channel
(B) Multiple channels
(C) Modulation
(D) None of the above
Answer: (A) Single channel
Q#10: Broadband signals use:
(A) Single frequency
(B) Multiple frequencies
(C) Only digital signals
(D) None of the above
Answer: (B) Multiple frequencies
Q#11: The process of converting digital data to analog signals is called:
(A) Demodulation
(B) Modulation
(C) Multiplexing
(D) Encoding
Answer: (B) Modulation
Q#12: The process of converting analog signals to digital data is called:
(A) Demodulation
(B) Modulation
(C) Sampling
(D) Transmission
Answer: (C) Sampling
(Note: Analog-to-digital conversion involves sampling, quantization, and encoding. Sampling is the first step.)
Q#13: Amplitude Shift Keying (ASK) modifies:
(A) Frequency
(B) Amplitude
(C) Phase
(D) Wavelength
Answer: (B) Amplitude
Q#14: Frequency Shift Keying (FSK) modifies:
(A) Amplitude
(B) Frequency
(C) Phase
(D) Bandwidth
Answer: (B) Frequency
Q#15: Phase Shift Keying (PSK) modifies:
(A) Amplitude
(B) Frequency
(C) Phase
(D) Time
Answer: (C) Phase
Q#16: Digital-to-Analog conversion is required for:
(A) Modems
(B) Ethernet
(C) Switches
(D) Hubs
Answer: (A) Modems
Q#17: Analog-to-Digital conversion is performed by:
(A) Modem
(B) ADC
(C) DAC
(D) Router
Answer: (B) ADC
Q#18: Sampling rate determines:
(A) Number of samples per second
(B) Bit rate
(C) Signal amplitude
(D) Frequency only
Answer: (A) Number of samples per second
Q#19: Nyquist theorem states:
(A) Sampling rate ≥ 2 × highest frequency
(B) Sampling rate = highest frequency
(C) Bit rate = 2 × bandwidth
(D) None of the above
Answer: (A) Sampling rate ≥ 2 × highest frequency
Q#20: Quantization is:
(A) Mapping analog amplitude to discrete levels
(B) Encoding digital data
(C) Multiplexing signals
(D) Transmission over fiber
Answer: (A) Mapping analog amplitude to discrete levels
Q#21: Bit rate refers to:
(A) Bits transmitted per second
(B) Signal power
(C) Number of users
(D) Frequency
Answer: (A) Bits transmitted per second
Q#22: Baud rate refers to:
(A) Number of bits per second
(B) Number of signal changes per second
(C) Bandwidth
(D) Delay
Answer: (B) Number of signal changes per second
Q#23: Bandwidth is:
(A) Maximum data transfer rate of a medium
(B) Signal amplitude
(C) Frequency of carrier
(D) Phase shift
Answer: (A) Maximum data transfer rate of a medium
Q#24: Signal-to-noise ratio (SNR) measures:
(A) Data rate
(B) Power ratio between signal and noise
(C) Bandwidth
(D) Phase
Answer: (B) Power ratio between signal and noise
Q#25: Digital signals have:
(A) Discrete levels
(B) Continuous waveforms
(C) Noise only
(D) Random patterns
Answer: (A) Discrete levels
Q#26: Analog signals have:
(A) Discrete levels
(B) Continuous waveforms
(C) Only 0 and 1
(D) Only bits
Answer: (B) Continuous waveforms
Q#27: Periodic analog signals are:
(A) Non-repeating
(B) Repeating at fixed intervals
(C) Digital
(D) None of the above
Answer: (B) Repeating at fixed intervals
Q#28: Non-periodic analog signals are:
(A) Repeating
(B) Non-repeating
(C) Always digital
(D) None
Answer: (B) Non-repeating
Q#29: Amplitude represents:
(A) Height of the wave
(B) Frequency of the wave
(C) Phase shift
(D) Bit rate
Answer: (A) Height of the wave
Q#30: Frequency represents:
(A) Wave height
(B) Number of cycles per second
(C) Signal power
(D) Bit duration
Answer: (B) Number of cycles per second
Q#31: Phase represents:
(A) Timing of the waveform
(B) Number of cycles
(C) Amplitude
(D) Data rate
Answer: (A) Timing of the waveform
Q#32: Which signal has higher resistance to noise?
(A) Analog
(B) Digital
(C) Both equal
(D) None
Answer: (B) Digital
Q#33: Encoding is:
(A) Representing data in signals
(B) Modulation
(C) Demodulation
(D) Multiplexing
Answer: (A) Representing data in signals
Q#34: Unipolar encoding uses:
(A) Two levels: positive and zero
(B) Positive and negative levels
(C) Three levels
(D) Frequency shifts
Answer: (A) Two levels: positive and zero
Q#35: Polar encoding uses:
(A) Only positive
(B) Positive and negative levels
(C) Three levels
(D) Phase only
Answer: (B) Positive and negative levels
Q#36: Bipolar encoding uses:
(A) Two levels only
(B) Three levels: positive, zero, negative
(C) Frequency shift
(D) Phase shift
Answer: (B) Three levels: positive, zero, negative
Q#37: Manchester encoding combines:
(A) Clock and data
(B) Only data
(C) Only frequency
(D) Only phase
Answer: (A) Clock and data
Q#38: Differential Manchester encoding uses:
(A) Transition at beginning indicates 0 or 1
(B) Only amplitude
(C) Only phase
(D) Only frequency
Answer: (A) Transition at beginning indicates 0 or 1
Q#39: Analog-to-digital conversion uses:
(A) Sampling, quantization, and encoding
(B) Only sampling
(C) Only modulation
(D) None
Answer: (A) Sampling, quantization, and encoding
Q#40: Digital-to-analog conversion is performed by:
(A) DAC
(B) ADC
(C) Modem
(D) Router
Answer: (A) DAC
Q#41: Nyquist rate is:
(A) Minimum sampling rate = 2 × max frequency
(B) Maximum frequency
(C) Bit rate
(D) Baud rate
Answer: (A) Minimum sampling rate = 2 × max frequency
Q#42: Pulse code modulation (PCM) is used to:
(A) Convert analog to digital
(B) Convert digital to analog
(C) Multiplex signals
(D) Modulate signals
Answer: (A) Convert analog to digital
Q#43: Amplitude modulation (AM) varies:
(A) Signal amplitude
(B) Frequency
(C) Phase
(D) Time
Answer: (A) Signal amplitude
Q#44: Frequency modulation (FM) varies:
(A) Signal frequency
(B) Signal amplitude
(C) Phase
(D) None
Answer: (A) Signal frequency
Q#45: Phase modulation (PM) varies:
(A) Phase
(B) Amplitude
(C) Frequency
(D) Bit rate
Answer: (A) Phase
Q#46: Analog signals are more:
(A) Susceptible to noise
(B) Resistant to noise
(C) Always digital
(D) None
Answer: (A) Susceptible to noise
Q#47: Digital signals are:
(A) Less affected by noise
(B) Highly affected by noise
(C) Continuous
(D) None
Answer: (A) Less affected by noise
Q#48: Bit interval is:
(A) Duration of a bit
(B) Number of bits per second
(C) Amplitude of bit
(D) Frequency of bit
Answer: (A) Duration of a bit
Q#49: Signal attenuation refers to:
(A) Loss of signal strength
(B) Increase of signal strength
(C) Encoding
(D) Modulation
Answer: (A) Loss of signal strength
Q#50: Signal distortion refers to:
(A) Alteration of waveform during transmission
(B) Increase of signal strength
(C) Sampling
(D) Modulation
Answer: (A) Alteration of waveform during transmission