# EC GATE 2008 (Test 3)

Tag: ec gate 2008
Q.1
Which of the following Boolean Expressions correctly represents the relation between P,Q,R and M1 A. M= (PORQ) XOR R
B. M= (PANDQ) XOR R
C. M= (PNORQ) XOR R
D. M= (PXORQ) XOR R
Explaination / Solution: Workspace
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Q.2
In the following circuit, the comparators output is logic “1” if V1 > V2 and is logic "0" otherwise. The D/A conversion is done as per the relation Volts, where b3 (MSB), b1,b2 and b0 (LSB) are the counter outputs. The counter starts from the clear state. The magnitude of the error between VDAC and Vin at steady state in volts is
A. 0.2
B. 0.3
C. 0.5
D. 1.0
Explaination / Solution:
No Explaination.

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Q.3
Assuming the OP-AMP to be ideal, the voltage gain of the amplifier shown below is A. B. C. D. Explaination / Solution: Workspace
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Q.4
The drain current of MOSFET in saturation is given by where K is a constant.
The magnitude of the transconductance gm is
A. B. C. D. Explaination / Solution: Workspace
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Q.5
Two identical NMOS transistors M1 and M2 are connected as shown below. Vbias is chosen so that both transistors are in saturation. The equivalent gm of the pair is defied to be at constant Vout
The equivalent gm of the pair is A.  the sum of individual gm's of the transistors
B.  the product of individual gm’s of the transistors
C.  nearly equal to the gm of M1
D.  nearly equal to gm/g0 of M2
Explaination / Solution:
No Explaination.

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Q.6
Consider the amplitude modulated (AM) signal For demodulating the signal using envelope detector, the minimum value of Ac should be
A. 2
B. 1
C. 0.5
D. 0
Explaination / Solution: Workspace
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Q.7
A rectangular waveguide of internal dimensions (a = 4 cm and b = 3 cm) is to be operated in TE11 mode. The minimum operating frequency is
A. 6.25 GHz
B. 6.0 GHz
C. 5.0 GHz
D. 3.75 GHz
Explaination / Solution: Workspace
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Q.8
Consider a Binary Symmetric Channel (BSC) with probability of error being p. To transmit a bit, say 1, we transmit a sequence of three 1s. The receiver will interpret the received sequence to represent 1 if at least two bits are 1. The probability that the transmitted bit will be received in error is
A.

p3 3p2(1 - p)

B. p3
C. (1 - p3)
D. pp2(1 - p)
Explaination / Solution:
No Explaination.

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Q.9
In the following network, the switch is closed at t = 0- and the sampling starts from t = 0. The sampling frequency is 10 Hz. The samples x(n), n = (0, 1, 2, ...) are given by
A.

5(1 - e-0.05n)

B. 5e-0.05n
C. 5(1 e-5n)
D. 5e-5n
Explaination / Solution:
No Explaination.

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Q.10
The magnitude of frequency responses of an underdamped second order system is 5 at 0 rad/sec and peaks to 10/at 5rad/sec. The transfer function of the system is
A. B. C. D.  