1
GATE ECE 2014 Set 4
MCQ (Single Correct Answer)
+2
-0.6
Consider a communication scheme where the binary valued signal X satisfies P{X = + 1} = 0.75 and P {X = - 1} = 0.25. The received signal Y = X + Z, where Z is a Gaussian random variable with zero mean and variance $${\sigma ^2}$$. The received signal Y is fed to the threshold detector. The output of the threshold detector $${\hat X}$$ is:
$$$\hat X:\left\{ {\matrix{
{ + \,1,} & {Y\, > \tau } \cr
{ - \,1,} & {Y\, \le \,\,\tau .} \cr
} } \right.$$$
To achieve a minimum probability of error $$P\{ \hat X\, \ne \,X\} $$, the threshold $$\tau $$ should be
2
GATE ECE 2014 Set 2
MCQ (Single Correct Answer)
+2
-0.6
Coherent orthogonal binary FSK modulation is used to transmit two equiprobable symbol waveforms $${s_1}\,(t)\, = \,\alpha \,\,\cos \,\,\,2\,\pi {f_1}\,t\,and\,\,{s_{2\,}}(t)\,\, = \,\alpha \,\,\cos \,\,\,2\,\pi {f_2}\,t$$, where $$\,\alpha = 4\,\,\,mV$$. Assume an AWGN channel with two-sided noise power spectral density $$\,{{{N_0}} \over 2} = 0.5\,\, \times \,{10^{ - 12}}$$ W/Hz. Using an optimal receiver and the relation $$Q(v) = {1 \over {\sqrt {2\,\pi } }}\,\int\limits_v^\infty {e{\,^{ - {u^2}/2}}} \,du$$, the bit error probability for a data rate of 500 kbps is
3
GATE ECE 2013
MCQ (Single Correct Answer)
+2
-0.6
Let U and V be two independent zero mean Gaussian random variables of variances $${{1 \over 4}}$$ and $${{1 \over 9}}$$ respectively. The probability $$P(\,3V\, \ge \,\,2U)$$ is
4
GATE ECE 2012
MCQ (Single Correct Answer)
+2
-0.6
A binary symmetric channel (BSC) has a transition probability of 1/8. If the binary transmit symbol X is such that P(X =0) = 9/10, then the probability of error for an optimum receiver will be
Questions Asked from Noise In Digital Communication (Marks 2)
Number in Brackets after Paper Indicates No. of Questions
GATE ECE 2016 Set 1 (2)
GATE ECE 2015 Set 2 (1)
GATE ECE 2015 Set 1 (2)
GATE ECE 2014 Set 4 (2)
GATE ECE 2014 Set 2 (1)
GATE ECE 2013 (1)
GATE ECE 2012 (2)
GATE ECE 2011 (2)
GATE ECE 2010 (2)
GATE ECE 2009 (2)
GATE ECE 2008 (1)
GATE ECE 2007 (5)
GATE ECE 2006 (2)
GATE ECE 2005 (3)
GATE ECE 2004 (1)
GATE ECE 2003 (2)
GATE ECE 2001 (1)
GATE ECE 1999 (2)
GATE ECE 1988 (2)
GATE ECE 1987 (1)
GATE ECE Subjects
Signals and Systems
Representation of Continuous Time Signal Fourier Series Fourier Transform Continuous Time Signal Laplace Transform Discrete Time Signal Fourier Series Fourier Transform Discrete Fourier Transform and Fast Fourier Transform Discrete Time Signal Z Transform Continuous Time Linear Invariant System Discrete Time Linear Time Invariant Systems Transmission of Signal Through Continuous Time LTI Systems Sampling Transmission of Signal Through Discrete Time Lti Systems Miscellaneous
Network Theory
Control Systems
Digital Circuits
General Aptitude
Electronic Devices and VLSI
Analog Circuits
Engineering Mathematics
Microprocessors
Communications
Electromagnetics