1

GATE ECE 2022

Numerical

+1

-0.33

Consider a channel over which either symbol x_{A} or symbol x_{B} is transmitted. Let the output of the channel Y be the input to a maximum likelihood (ML) detector at the receiver. The conditional probability density functions for y given x_{A} and x_{B} are :

$${f_{\left. Y \right|{x_A}}}(y) = {e^{ - (y + 1)}}u(y + 1)$$,

$${f_{\left. Y \right|{x_B}}}(y) = {e^{(y - 1)}}(1 - u(y - 1))$$,

where, u( . ) is the standard unit step function. The probability of symbol error for this system is _________ (rounded off to two decimal places).

Your input ____

2

GATE ECE 2017 Set 1

MCQ (Single Correct Answer)

+1

-0.3

In a digital communication system, the overall pulse shape p(t) at the receiver before the
sampler has the Fourier transform P(f). If the symbols are transmitted at the rate of 2000
symbols per second, for which of the following cases is inter symbol interference zero?

3

GATE ECE 2017 Set 1

MCQ (Single Correct Answer)

+1

-0.3

Which one of the following statements about differential pulse code modulation (DPCM) is true?

4

GATE ECE 2016 Set 2

Numerical

+1

-0

A speech signal is sampled at 8 kHz and encoded into PCM format using 8 bits/sample. The PCM data is transmitted through a baseband channel via 4-level PAM. The minimum bandwidth (in kHz) required for transmission is _________.

Your input ____

Questions Asked from Digital Communication Systems (Marks 1)

Number in Brackets after Paper Indicates No. of Questions

GATE ECE Subjects

Signals and Systems

Representation of Continuous Time Signal Fourier Series Discrete Time Signal Fourier Series Fourier Transform Discrete Time Signal Z Transform Continuous Time Linear Invariant System Transmission of Signal Through Continuous Time LTI Systems Discrete Time Linear Time Invariant Systems Sampling Continuous Time Signal Laplace Transform Discrete Fourier Transform and Fast Fourier Transform Transmission of Signal Through Discrete Time Lti Systems Miscellaneous Fourier Transform

Network Theory

Control Systems

Digital Circuits

General Aptitude

Electronic Devices and VLSI

Analog Circuits

Engineering Mathematics

Microprocessors

Communications

Electromagnetics