1
GATE ECE 2011
MCQ (Single Correct Answer)
+2
-0.6
A four phase and an eight-phase signal constellation are shown in the figure below.
![GATE ECE 2011 Communications - Noise In Digital Communication Question 10 English](https://imagex.cdn.examgoal.net/QJ5FjjWHvlIw4lUDb/X1SA6k5Vs69Qy0s4CwFo3YwidDXK3/LgfRH7wKgHNP6uxJVY5ox3/uploadfile.jpg)
For the constraint that the minimum distance between pairs of signal points be d for both constellations, the radii r1, and r2 of the circles are
2
GATE ECE 2011
MCQ (Single Correct Answer)
+2
-0.6
A four phase and an eight-phase signal constellation are shown in the figure below.
![GATE ECE 2011 Communications - Noise In Digital Communication Question 9 English](https://imagex.cdn.examgoal.net/QJ5FjjWHvlIw4lUDb/X1SA6k5Vs69Qy0s4CwFo3YwidDXK3/LgfRH7wKgHNP6uxJVY5ox3/uploadfile.jpg)
Assuming high SNR and that all signals are equally probable, the additional average transmitted signal energy required by the 8-PSK signal to achieve the same error probability as the 4-PSK signal is
3
GATE ECE 2010
MCQ (Single Correct Answer)
+2
-0.6
Consider a base band binary PAM receiver shown below. The additive channel noise
$$n(t)$$ is white with power spectral density $${S_N}\left( f \right) = {N_0}/2 = {10^{ - 20}}$$ $$W/Hz$$. The low-pass filter
is ideal with unity gain and cut -off frequency $$1MHz$$. Let $${Y_k}$$ represent the random variable $$y\left( {{t_k}} \right)$$.
$${Y_k} = {N_k}$$ if transmitted bit $${b_k} = 0$$
$${Y_k} = a + {N_k}$$ if transmitted bit $${b_k} = 1$$
Where $${b_k} = 0$$ represents the noise sample value. The noise sample has a probability density function, $${P_{{N_k}}}\left( n \right)\,\,\,\,\,\,\, = 0.5\alpha {e^{ - \alpha \left| n \right|}}$$ (This has mean zero and variance $$2/{\alpha ^2}$$). Assume transmitted bits to be equiprobable and threshold $$z$$ is set to $$a/2 = {10^{ - 6}}V$$.
$${Y_k} = {N_k}$$ if transmitted bit $${b_k} = 0$$
$${Y_k} = a + {N_k}$$ if transmitted bit $${b_k} = 1$$
Where $${b_k} = 0$$ represents the noise sample value. The noise sample has a probability density function, $${P_{{N_k}}}\left( n \right)\,\,\,\,\,\,\, = 0.5\alpha {e^{ - \alpha \left| n \right|}}$$ (This has mean zero and variance $$2/{\alpha ^2}$$). Assume transmitted bits to be equiprobable and threshold $$z$$ is set to $$a/2 = {10^{ - 6}}V$$.
![GATE ECE 2010 Communications - Noise In Digital Communication Question 14 English](https://gateclass.cdn.examgoal.net/UKfUuPIUHolxISO9U/kXOkz9ZVbiqmQXiaOWCkUmGQuLR9C/KmuLomeIN1i0EStyXd2Nyc/uploadfile.jpg)
The value of the parameter $$\alpha $$( in V-1 ) is
4
GATE ECE 2010
MCQ (Single Correct Answer)
+2
-0.6
Consider a base band binary PAM receiver shown below. The additive channel noise
$$n(t)$$ is white with power spectral density $${S_N}\left( f \right) = {N_0}/2 = {10^{ - 20}}$$ $$W/Hz$$. The low-pass filter
is ideal with unity gain and cut -off frequency $$1MHz$$. Let $${Y_k}$$ represent the random variable $$y\left( {{t_k}} \right)$$.
$${Y_k} = {N_k}$$ if transmitted bit $${b_k} = 0$$
$${Y_k} = a + {N_k}$$ if transmitted bit $${b_k} = 1$$
Where $${b_k} = 0$$ represents the noise sample value. The noise sample has a probability density function, $${P_{{N_k}}}\left( n \right)\,\,\,\,\,\,\, = 0.5\alpha {e^{ - \alpha \left| n \right|}}$$ (This has mean zero and variance $$2/{\alpha ^2}$$). Assume transmitted bits to be equiprobable and threshold $$z$$ is set to $$a/2 = {10^{ - 6}}V$$.
$${Y_k} = {N_k}$$ if transmitted bit $${b_k} = 0$$
$${Y_k} = a + {N_k}$$ if transmitted bit $${b_k} = 1$$
Where $${b_k} = 0$$ represents the noise sample value. The noise sample has a probability density function, $${P_{{N_k}}}\left( n \right)\,\,\,\,\,\,\, = 0.5\alpha {e^{ - \alpha \left| n \right|}}$$ (This has mean zero and variance $$2/{\alpha ^2}$$). Assume transmitted bits to be equiprobable and threshold $$z$$ is set to $$a/2 = {10^{ - 6}}V$$.
![GATE ECE 2010 Communications - Noise In Digital Communication Question 12 English](https://gateclass.cdn.examgoal.net/UKfUuPIUHolxISO9U/kXOkz9ZVbiqmQXiaOWCkUmGQuLR9C/KmuLomeIN1i0EStyXd2Nyc/uploadfile.jpg)
The probability of bit error is
Questions Asked from Noise In Digital Communication (Marks 2)
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GATE ECE 2016 Set 1 (2)
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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