Communications
Analog Communication Systems
Marks 1Marks 2
Digital Communication Systems
Marks 1Marks 2Marks 8Marks 10
Random Signals and Noise
Marks 1Marks 2Marks 4
Fundamentals of Information Theory
Marks 1Marks 2
Noise In Digital Communication
Marks 1Marks 2
1
GATE ECE 2007
MCQ (Single Correct Answer)
+2
-0.6
An input to a 6-level quantizer has the probability density function f(X) as shown in the figure. Decision boundaries of the quantizer are chosen so as to maximize the entropy of the quantizer output. It is given that 3 consecutive decision boundaries are ‘-1’, ‘0’ and ‘1’. GATE ECE 2007 Communications - Noise In Digital Communication Question 22 English

Assuming that the reconstruction levels of the quantizer are the mid-points of the decision boundaries, the ratio of signal power to quantization noise power is

A
$${152 \over 9}$$
B
$${64 \over 3}$$
C
$${76 \over 3}$$
D
$$28$$
2
GATE ECE 2007
MCQ (Single Correct Answer)
+2
-0.6
Two 4-ray signal constellations are shown. It is given that $${\phi _1}$$ and $${\phi _2}$$ constitute an orthonormal basis for the two constellations. Assume that the four symbols in both the constellations are equiprobable. Let $${{{N_0}} \over 2}$$ denote the power spectral density of white Gaussian noise. GATE ECE 2007 Communications - Noise In Digital Communication Question 21 English

The ratio of the average energy of Constellation 1 to the average energy of Constellation 2 is

A
$$4{a^2}$$
B
$$4$$
C
$$2$$
D
$$8$$
3
GATE ECE 2007
MCQ (Single Correct Answer)
+2
-0.6
Two 4-ray signal constellations are shown. It is given that $${\phi _1}$$ and $${\phi _2}$$ constitute an orthonormal basis for the two constellations. Assume that the four symbols in both the constellations are equiprobable. Let $${{{N_0}} \over 2}$$ denote the power spectral density of white Gaussian noise. GATE ECE 2007 Communications - Noise In Digital Communication Question 20 English

If these constellations are used for digital communications over an AWGN channel, then which of the following statements is true?

A
Probability of symbol error for Constellation 1 is lower
B
Probability of symbol error for Constellation 1 is higher
C
Probability of symbol error is equal for both the constellations
D
The value of N0 will determine which of the two constellations has a lower probability of symbol error.
4
GATE ECE 2006
MCQ (Single Correct Answer)
+2
-0.6
Let $$g\left( t \right){\mkern 1mu} {\mkern 1mu} \,\,\,\,\,{\mkern 1mu} = {\mkern 1mu} {\mkern 1mu} p\left( t \right){}^ * p\left( t \right)$$ where $$ * $$ denotes convolution and $$p(t) = u(t) - u(t-1)$$ with $$u(t)$$ being the unit step function

The impulse response of filter matched to the signal $$s(t) = g(t)$$ $$ - \delta {\left( {t - 2} \right)^ * }\,\,g\left( t \right)$$ is given as:

A
$$s\left( {1 - t} \right)$$
B
$$ - s\left( {1 - t} \right)$$
C
$$ - s\left( t \right)$$
D
$$ s\left( t \right)$$
GATE ECE Subjects
Signals and Systems
Network Theory
Control Systems
Digital Circuits
General Aptitude
Electronic Devices and VLSI
Analog Circuits
Engineering Mathematics
Microprocessors
Communications
Electromagnetics