R4RIN – MCQs, Mock Tests | Electrical measurements Digital Communications MCQs set-1

Which circuit is called as regenerative repeaters?

1. Analog circuits
2. Digital circuits
3. Amplifiers
4. A/D converters

✅ Correct Answer: 2

What are the advantages of digital circuits?

1. Less noise
2. Less interference
3. More flexible
4. All of the mentioned

✅ Correct Answer: 4

How many bytes does a gigabyte have?

1. 1 million bytes
2. 10 million bytes
3. 1 billion bytes
4. 10 billion bytes

✅ Correct Answer: 3

What is the ASCII value of space?

1. 32
2. 48
3. 96
4. 65

✅ Correct Answer: 1

Which block or device does the data compression?

1. Channel encoder
2. Source encoder
3. Modulator
4. None of the mentioned

✅ Correct Answer: 2

What is the code rate?

1. k/n
2. n/k
3. All of the mentioned
4. None of the mentioned

✅ Correct Answer: 1

Pulse shaping is done by which block or system?

1. Encoder
2. Baseband modulator
3. Pulse code modulator
4. Demodulator

✅ Correct Answer: 3

Equalizer is used for?

1. Filtering
2. Diminish distortion
3. All of the mentioned
4. None of the mentioned

✅ Correct Answer: 3

Source coding block is used for?

1. Compressing
2. Digitizing
3. A/D conversion
4. All of the mentioned

✅ Correct Answer: 4

Which measurement considers phase as an important parameter?

1. Coherent
2. Non-coherent
3. All of the mentioned
4. None of the mentioned

✅ Correct Answer: 1

What is the period of a signal x(t)?

1. T
2. 2T
3. T/2
4. None of the mentioned

✅ Correct Answer: 1

Which of the given signals are periodic?

1. x(t) = 4 cos(5πt)
2. x(t) = u(t) – 1/2
3. x(t) = 4u(t) + 2sin(3t)
4. x[n] = 2sin(3n)

✅ Correct Answer: 1

Check whether the signal is periodic or not? x(t) = cos(4t) + 2sin(8t)

1. Periodic with period π/2
2. Periodic with period 2
3. Periodic with period 2/π
4. Not periodic

✅ Correct Answer: 1

Find the periodicity of the following signal. x(t)=cos((2π/7)t)sin((3π/5)t)

1. 30
2. 7
3. 35
4. 5/3

✅ Correct Answer: 3

Find the fundamental period of 1+sin^2 (3π/5)n.

1. 10/3
2. 5
3. 3π/5
4. None of the mentioned

✅ Correct Answer: 2

Which signal is called as energy signal?

1. Finite energy and zero power
2. Finite energy and non-zero power
3. Infinite energy and zero power
4. Infinite energy and non-zero power

✅ Correct Answer: 1

Which signal is said to be power signal?

1. Infinite power and zero energy
2. Infinite power and non-zero energy
3. Finite power and infinite energy
4. Finite power and zero energy

✅ Correct Answer: 3

Continuous Impulse signal is a power or energy signal?

1. Power signal
2. Energy signal
3. Both power and energy
4. Neither power nor energy signal

✅ Correct Answer: 4

Discrete impulse signal is a power or energy signal?

1. Power signal
2. Energy signal
3. Both power and energy signal
4. Neither power or energy signal

✅ Correct Answer: 2

A unit impulse function has?

1. Large amplitude
2. Zero pulse width
3. Unity weight
4. All of the mentioned

✅ Correct Answer: 4

Power spectral density function is a?

1. Real and even function
2. Non negative function
3. Periodic
4. All of the mentioned

✅ Correct Answer: 4

Energy spectral density defines

1. Signal energy per unit area
2. Signal energy per unit bandwidth
3. Signal power per unit area
4. Signal power per unit bandwidth

✅ Correct Answer: 2

Power spectrum describes distribution of _________ under frequency domain.

1. Mean
2. Variance
3. Gaussian
4. None of the mentioned

✅ Correct Answer: 2

How can power spectral density of non periodic signal be calculated?

1. By integrating
2. By truncating
3. By converting to periodic
4. None of the mentioned

✅ Correct Answer: 2

What is Wiener-Khinchin theorem?

1. Spectral density and auto-covariance makes a fourier transform pair
2. Spectral density and auto-correlatioon makes a fourier tranform pair
3. Spectral density and variance makes a fourier tranform pair
4. None of the mentioned

✅ Correct Answer: 2

According to Parseval’s theorem the energy spectral density curve is equal to?

1. Area under magnitude of the signal
2. Area under square of the magnitude of the signal
3. Area under square root of magnitude of the signal
4. None of the mentioned

✅ Correct Answer: 2

Spectogram is the graph plotted against?

1. Frequency domain
2. Time domain
3. Frequency & Time domain
4. None of the mentioned

✅ Correct Answer: 2

Autocorrelation is a function which matches

1. Two same signals
2. Two different signal
3. One signal with its delayed version
4. None of the mentioned

✅ Correct Answer: 3

Autocorrelation is a function of

1. Time
2. Frequency
3. Time difference
4. Frequency difference

✅ Correct Answer: 3

Autocorrelation is maximum at _______

1. Unity
2. Origin
3. Infinite point
4. None of the mentioned

✅ Correct Answer: 2

Autocorrelation function of periodic signal is equal to _______

1. Energy of the signal
2. Power of the signal
3. Its area in frequency domain
4. None of the mentioned

✅ Correct Answer: 2

Autocorrelation is a _______ function.

1. Real and even
2. Real and odd
3. Complex and even
4. Complex and odd

✅ Correct Answer: 1

Autocorrelation function of white noise will have?

1. Strong peak
2. Infinite peak
3. Weak peak
4. None of the mentioned

✅ Correct Answer: 1

Random variables give relationship between _____

1. Two random events
2. Probability of occurence of two random events
3. Random event and a real number
4. Random event and its probability of occurrence

✅ Correct Answer: 3

The distribution function of random variable is

1. P(X less than or equal to x)
2. P(X greater than or equal to x)
3. P(X less than x)
4. P(X greater than x)

✅ Correct Answer: 1

The distribution function of -(infinity) and (infinity) is _____

1. 0 and 1
2. 1 and 0
3. Both 0
4. Both 1

✅ Correct Answer: 1

The value of the probability density function of random variable is

1. Positive function
2. Negative function
3. Zero
4. One

✅ Correct Answer: 1

Which gives the measure of randomness of the random variable?

1. Mean
2. Variance
3. Standard variance
4. Pdf

✅ Correct Answer: 2

Random process is a function of ______

1. Random event and time
2. Random event and frequency
3. Random event and real number
4. None of the mentioned

✅ Correct Answer: 1

A random process is called as stationary in strict sense if

1. Its statistics vary with shift in time origin
2. Its statistics does not vary with shift in time origin
3. Its autocorrelation vary with shift in time
4. Its autocorrelation does not vary with shift in time

✅ Correct Answer: 1

For a stationary process, autocorrelation function depends on

1. Time
2. Time difference
3. Does not depend on time
4. None of the mentioned

✅ Correct Answer: 2

The autocorrelation function is maximum at

1. Origin
2. Infinity
3. Origin & Infinity
4. None of the mentioned

✅ Correct Answer: 1

White noise has _____ mean and ______ variance.

1. Zero and zero
2. Finite and zero
3. Zero and finite
4. One and zero

✅ Correct Answer: 3

The process of data conversion along with formatting the data is called as ______

1. Formatting
2. Modulation
3. Source coding
4. Amplifying

✅ Correct Answer: 3

Formatting is the process which includes

1. Pulse code modulation
2. Sampling
3. Quantization
4. All of the mentioned

✅ Correct Answer: 4

Analog information is converted to digital data using

1. Sampling
2. Quantization
3. Coding
4. All of the mentioned

✅ Correct Answer: 4

The process that transforms text into binary digits is called as _______

1. Binary coding
2. Data coding
3. Character coding
4. Sampling

✅ Correct Answer: 3

For the number of bits, k=1 and number of symbols, M=2 the system is called as

1. Unary
2. Binary
3. Quarternary
4. None of the mentioned

✅ Correct Answer: 2

Perform the bit stream partitioning and find the 8-ary waveform for the word ‘THINK’.

1. 1204443464
2. 4643444021
3. 1240443464
4. none of the mentioned

✅ Correct Answer: 1

Find the 32-ary waveform for the word ‘THINK’.

1. 514172520
2. 202517415
3. 541172520
4. None of the mentioned

✅ Correct Answer: 1