Electronics and Communication Engineering
GATE ECE Random processes PYQs
Build your understanding with focused practice from past exam papers.
How to practice Random processes
Attempt a question, record the concept and assumptions, then check the available answer. Rework mistakes after revising the relevant concepts. Topic tags can overlap; review the question context.
Questions 1–10 of 14. Imported answers require independent review unless marked reviewed.
Question 42
Open questionECMCQ2 marksNeeds review
Consider a real-valued random process
where
and
is a positive integer. Here,
for
and 0 otherwise. The coefficients
are pairwise independent, zero-mean unit-variance random variables.Read the following statements about the random process and choose the correct option.
(i) The mean of the process
is independent of time
.(ii) The autocorrelation function
is independent of time
for all
.(Here,
is the expectation operation.)Your answerChoose one option.
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Open questionECMCQ1 markNeeds review
A white Gaussian noise
with zero mean and power spectral density
, when applied to a first-order RC low pass filter produces an output
. At a particular time
, the variance of the random variable
is ______.Your answerChoose one option.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 57
Open questionECNAT2 marksNeeds review
Let
be a random process, where amplitude
and phase
are independent of each other, and are uniformly distributed in the intervals
and
, respectively.
is fed to an 8-bit uniform mid-rise type quantizer. Given that the autocorrelation of
is
, the signal to quantization noise ratio (in dB, rounded off to two decimal places) at the output of the quantizer is __________.Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 30
Open questionECMSQ1 markNeeds review
For a real signal, which of the following is/are valid power spectral density/densities?
Your answerSelect all correct options. You can choose more than one.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 59
Open questionECNAT2 marksNeeds review
Let
be a white Gaussian noise with power spectral density
W/Hz. If
is input to an LTI system with impulse response
. The average power of the system output is ________ W (rounded off to two decimal places).Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 23
Open questionECMCQ1 markNeeds review
The frequency response
of a linear time-invariant system has magnitude as shown in the figure.Statement I: The system is necessarily a pure delay system for inputs which are bandlimited to
.Statement II: For any wide-sense stationary input process with power spectral density
, the output power spectral density
obeys
for
.Which one of the following combinations is true?

Your answerChoose one option.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 48
Open questionECMSQ2 marksNeeds review
A state transition diagram with states
,
, and
, and transition probabilities
is shown in the figure (e.g.,
denotes the probability of transition from state A to B). For this state diagram, select the state(s) which is/are universally true. 
Your answerSelect all correct options. You can choose more than one.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 21
Open questionECNAT1 markNeeds review
The autocorrelation function
of a wide-sense stationary random process
is shown in the figure. The average power of
is ______.

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Open questionECNAT1 markNeeds review
The random variable
and
is a real white Gaussian noise process with two-sided power spectral density
W/Hz, for all
. The variance of Y is ______.Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 45
Open questionECNAT2 marksNeeds review
Let a random process
be described as
, where
is a white noise process with power spectral density
. The filter
has a magnitude response given by
for
, and zero elsewhere.
is a stationary random process, uncorrelated with
, with power spectral density as shown in the figure. The power in
, in watts, is equal to ______ W (rounded off to two decimal places). 
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