Digital Signal Processing Question Paper-GATE & PSU Exam

Last updated on March 20th, 2025 at 03:27 am

Here, We will see the Digital Signal Processing Question Paper from the previous year’s exam and the syllabus of Digital Signal Processing for the GATE and PSU Exam.

1. Digital Signal Processing

Digital Signal Processing testing candidates’ understanding of signal analysis, transformation, and system design, making it a critical component of the syllabus.
GATE questions often test conceptual clarity through numerical problems (e.g., calculating DFT coefficients, and filter order).
PSUs may include descriptive questions on real-world DSP applications.

2. Digital Signal Processing Syllabus

The Digital Signal Processing Questions asked in the GATE and PSU Exam focused on topics:

• Discrete-time signals and systems: Sampling, quantization, LTI systems.
• Fourier analysis: DTFT, DFT, FFT algorithms, spectral leakage.
• Z-transform: ROC, inverse transforms, system stability.
• Digital filter design: FIR/IIR filters, windowing techniques.
• Multirate DSP: Decimation, interpolation.

3. PSU – Digital Signal Processing Syllabus:

• Applications in communication systems, image processing, and audio coding.
• Adaptive filters, noise reduction, and real-time DSP implementations.
• Overlap with GATE topics, emphasizing practical problem-solving.

Digital Signal Processing Question Paper – GATE & PSU Exam

Q. At a room temperature of 300K, calculate the thermal noise generated by two resistors of 10KΩ and 20KΩ when the bandwidth is 10KHz.

1. 1.2868×10^-6V, 1.819×10^-6V
2. 6.08×10^-6V, 15.77×10^-6V
3. 16.06×10^-6V, 2.356×10^-6V
4. 1.66×10^-6V, 0.23×10^-6V

Answer

1.2868×10^-6V, 1.819×10^-6V
NIELIT 2017 July Scientist B (CS)

Q. The open-loop transfer function of a feedback control system is G(s)•H(s) = 1/(S+1)³. The gain margin of the system is

1. 2
2. 4
3. 8
4. 16

Answer

8
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. The IETF standard documents are called

1. RFC
2. RCF
3. ID
4. none of the above

Answer

RFC
NIELIT 2016 DEC Scientist B (CS)

Q. A low pass filter is

1. Passes the frequencies lower than the specified cut-off frequency
2. Used to recover the signal from the sampled signal
3. Rejects higher frequencies
4. All of the above

Answer

All of the above
NIELIT 2016 DEC Scientist B (CS)

Q. T1 carrier system is used:

1. For delta modulation
2. Industrial noise
3. For frequency-modulated signals
4. None of the above

Answer

None of the above
NIELIT 2016 DEC Scientist B (CS)

Q. A high-resolution B/w TV picture contains 3×106picture elements and 16 different brightness levels. Pictures are repeated at a rate of 24 per second. All levels have an equal likelihood of occurrence and all picture elements are assumed to be independent. What will be the average rate of information carried by this TV picture source?

1. 288 Mbps
2. 24 Mbps
3. 132 Mbps
4. 3 Mbps

Answer

288 Mbps
NIELIT 2021 Dec Scientist B

Q. For 8–ary signal or symbol the number of likelihood functions are :

1. 16
2. 8
3. 9
4. 64

Answer

8
NIELIT 2021 Dec Scientist A

Q. In a paging scheme if the page size is 2048 bytes, then while accommodating a process of 72, 766 bytes, how much internal fragmentation occurs?

1. 962 bytes
2. 2048 bytes
3. 1024 bytes
4. 1086 bytes

Answer

962 bytes
NIELIT 2021 Dec Scientist B

Q. In VCO, the output frequency is a linear function of its input :

1. Frequency
2. Voltage
3. Time period
4. None of the option

Answer

Voltage
NIELIT 2021 Dec Scientist A

Q. At 100% modulation, the power in each sideband is ___ of that of the carrier.

1. 50%
2. 40%
3. 60%
4. 25%

Answer

25%
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. A sinusoidal signal is an analog signal, because:

1. it can have a number of values between the negative and positive peaks
2. it is negative for one half-cycle
3. it is positive for one half-cycle
4. it has positive as well as negative values

Answer

it can have a number of values between the negative and positive peaks
NIELIT 2016 DEC Scientist B (CS)

Q. The noise due to the random behavior of charge carriers is:

1. Partition noise
2. Industrial noise
3. Shot noise
4. Flicker noise

Answer

Shot noise
NIELIT 2016 DEC Scientist B (CS)

Q. The bit transmission rate in a pulse-coded modulation system with a number of quantization levels 8 and a maximum signal frequency of 4000 Hz is given by

1. 16 kbps
2. 24 kbps
3. 32 kbps
4. 8 kbps

Answer

32 kbps
NIELIT 2021 Dec Scientist B

Q. The astable multivibrator has

1. two quasi-stable states
2. two stable states
3. one stable and one quasi-stable state
4. none of these

Answer

none of these
NIELIT 2016 MAR Scientist C

Q. Which of the following is possible in a token-passing bus network?

1. in-service expansion.
2. unlimited number of stations.
3. both (A) and (B).
4. unlimited distance.

Answer

in-service expansion.
NIELIT 2016 MAR Scientist B

Q. The covariance function of a band-limited white noise is :

1. A Dirac delta function
2. An exponentially decreasing function
3. A sinc function
4. A sinc2 function

Answer

A Dirac delta function
NIELIT 2021 Dec Scientist A

Q. The channel capacity of a noise-free channel having M symbols is given by :

1. M
2. 2^M
3. logM
4. None of these

Answer

logM
NIELIT 2021 Dec Scientist B

Q. A stable multivibrator is used as

1. comparator circuit
2. squaring circuit
3. frequency to voltage converter
4. voltage to frequency converter

Answer

squaring circuit
NIELIT 2016 MAR Scientist C

Q. To simulate an analog signal of frequency f, the bandwidth requirement of the channel is :

1. 2f
2. f
3. f/2
4. f/4

Answer

2f
NIELIT 2021 Dec Scientist A

Q. In MOSFET fabrication, the channel; length is defined during the process of

1. Isolation oxide growth
2. Channel stop implantation
3. Poly-silicon gate patterning
4. The lithography step leading to the contact pad

Answer

Poly-silicon gate patterning
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. The sequence of operation in which PCM is done is

1. Sampling, quantizing, encoding
2. Quantizing, sampling, encoding
3. Quantizing, encoding, sampling
4. None of the above

Answer

Sampling, quantizing, encoding
NIELIT 2016 DEC Scientist B (CS)

Q. An analog signal having 3KHz bandwidth is sampled at 1.5 times the Nyquist rate. The successive samples are statistically independent. Each sample is quantized into one of 256 equally likely levels. The information rate of the source is

1. 3 kbps
2. 72 kbps
3. 256 kbps
4. 9 kbps

Answer

72 kbps
NIELIT 2021 Dec Scientist B

Q. A carrier A_c cos(ω_c)t is frequency modulated by a signal E_m cos(ωm)t. The modulation index is mf. The expression for the resulting FM signal is

1. A_c cos[ω_ct + mf sin(ω_m)t]
2. A_c cos[ω_ct + mf cos(ω_m)t]
3. A_c cos[ω_ct + πmf sin(ω_m)t]
4. A_c cos[ω_ct + 2πmf E_mEm cos(ω_m)t/ω_m]

Answer

A_c cos[ω_ct + mf sin(ω_m)t]
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. A modulating signal m(t) = 10cos(2π×10³t) is amplitude modulated with a carrier signal c(t) = 50cos(2π×10⁵t) Assume R=1Ω. Find the carrier power required for transmitting this AM wave.

1. 1000 W
2. 1250 W
3. 1100 W
4. 50 W

Answer

1250 W
NIELIT 2021 Dec Scientist A

Q. If the number of bits per sample in a PCM system is increased from a n to n+1, the improvement in signal to quantization nose ratio will be

1. 3 dB
2. 6 dB
3. 2n dB
4. n dB

Answer

6 dB
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. For a periodic signal v(t) = 30 sin100t + 10 cos300t + 6 sin(500t+π/4), the fundamental frequency in rad/s

1. 100
2. 300
3. 500
4. None of these

Answer

100
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. y = 10cos(1800πt)+20cos(2000πt)+10cos(220πt). Find the modulation index (μ) of the given wave.

1. 0.3
2. 0.5
3. 0.7
4. 1

Answer

0.5
NIELIT 2021 Dec Scientist B

Q. For the discrete signal x[n] = aⁿu[n], a>0 the -transform is

1. (z+a)/z
2. (z-a)/z
3. z/(z-a)
4. z/(z+a)

Answer

z/(z-a)
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. Energy of power signal is :

1. Finite
2. Zero
3. Infinite
4. 1

Answer

Infinite
NIELIT 2021 Dec Scientist A

Q. Calculate the modulation percentage if the modulating signal is 8V and the carrier is 12V?

1. 50
2. 67
3. 150
4. 33

Answer

67
NIELIT Scientist B 2020 November

Q. The resistance to be connected across terminals a, and b for maximum power transfer to it is:

1. 40 Ω
2. 5 Ω
3. 2.5 Ω
4. 10 Ω

Answer

5 Ω
NIELIT Scientist B 2020 November

Q. A company needs to develop digital signal processing software for one of its newest inventions. The software is expected to have 40000 lines of code. The company needs to determine the effort in person months needed to develop this software using the basic COCOMO model. The multiplicative factor for this model is given as 2.8 for the software development on embedded systems, while the exponentiation factor is given as 1.20. What is the estimated effort in person-months?

1. 234.25
2. 932.50
3. 287.80
4. 122.40

Answer

287.80
NIELIT 2022 April Scientist B

Q. The final value theorem is used to find the

1. Steady-state value of the system output
2. The initial value of the system output
3. Transient behavior of the system output
4. None of these

Answer

Steady state value of the system output
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. The capacity relationship is given by

1. C = W log₂(1+S/N)
2. C = 2W log₂(1+S/N)
3. C = W log₂(1-S/N)
4. C = W log₁₀(1+S/N)

Answer

C = W log₂(1+S/N)
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. An ideal op-amp is an ideal

1. voltage-controlled current source
2. voltage-controlled voltage source
3. current controlled source
4. current controlled voltage source

Answer

voltage controlled voltage source
NIELIT 2017 OCT Scientific Assistant A (CS)

Q. Twelve 1Ω resistances are used as edges to form a cube. The resistance between two diagonally opposite corners of the cube is

1. 5/6 Ω
2. 1/6 Ω
3. 6/5 Ω
4. 3/2 Ω
   NIELIT 2017 OCT Scientific Assistant A (CS)

Answer

5/6 Ω

Q. In a baseband communication link, frequencies up to 3500 Hz are used for signaling. Using a raised cosine pulse with 75% excess bandwidth and for no inter-symbol interference, the maximum possible signaling rate is symbols per sec is:

1. 1750
2. 2625
3. 4000
4. 5250

Answer

4000
NIELIT 2022 April Scientist B

Q. Consider a disk pack with a seek time of 4 milliseconds and rotational speed of 10000 rotations per minute (RPM). It has 600 sectors per track and each sector can store 512 bytes of data. Consider a file stored on the disk. The file contains 2000 sectors. Assume that every sector access necessitates a seek, and the average rotational latency for accessing each sector is half of the time for one complete rotation. The total time (in milliseconds) needed to read the entire file is _______

1. 14020
2. 14000
3. 25030
4. 15000

Answer

14020
NIELIT 2022 April Scientist B

Q. The term in the MVC architecture that receives events is called _____.

1. Receiver
2. Controller
3. Transmitter
4. Modulator

Answer

Controller
NIELIT Scientific Assistant A 2020 November

Q. Consider sinusoidal modulation in an AM system. Assuming no over modulation, the modulation index (µ) when the maximum and minimum values of the envelope, respectively, are 3V and 1V is _______.

1. 0.1
2. 0
3. 0.3
4. 0.5

Answer

0.5
NIELIT 2022 April Scientist B

Q. A 1 MHz sinusoidal carrier is amplitude modulated by a symmetrical square wave of period 100 µsec. Which of the following frequencies will not be present in the modulated signal?

1. 990 MHz
2. 1010 MHz
3. 1020 MHz
4. 1030 MHz

Answer

1020 MHz
NIELIT 2022 April Scientist B