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1.
Statement for Linked Answer Questions::
The impulse response h(t) of a linear time invariant continuous time system is given by h(t) = exp(-2t)u(t), where u(t) denotes the unit step function.
[1] The frequency response H(ω) of this system in terms of angular frequency ω is given by H(ω) [2 marks]
(A) 1/(1+ j2ω)
(B) sinω /ω
(C) 1/(2+jω)
(D) jω/(2+jω)[2] The output of this system to the sinusoidal input x (t) = 2cos (2t) for all time t, is [2 marks]
(A) 0
(B) 2-0.25 cos(2t-0.125π)
(C) 2-0.5 cos(2t-0.125π)
(D) 2-0.5 cos(2t-0.25π)last reply by CpjJwWHV • 14 years ago • asked in Electronics and Communication Engineering, 2008
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2.
Statement for Linked Answer Questions::
In the following circuit, the comparator output is logic “I” if V1 > V2 and is logic “0” otherwise. The D/A conversion is done as per the relations
, where b3 (MSB) ,b2 , b1 and b0 (LSB) are the counter outputs
The counter starts from the clear state
[1] The stable reading of the LED display is [2 marks]
(A) 06
(B) 07
(C) 12
(D) 13[2] The magnitude of the error between VDAC and Vin at steady state in volts is
[2 marks]
(A) 0.2
(B) 0.3
(C) 0.5
(D) 1.0asked in Electronics and Communication Engineering, 2008
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3.
Statement for Linked Answer Questions::
In the following transistor circuit VBE = 0.7V, rc = 25mV/IE, and β and all the capacitances are very large
[1] The value of DC current IE is [2 marks]
(A) 1mA
(B) 2mA
(C) 5mA
(D) 10mA[2] The mid-band voltage gain of the amplifier is approximately [2 marks]
(A) -180
(B) -120
(C) -90
(D) -60asked in Electronics and Communication Engineering, 2008
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4.
Statement for Linked Answer Questions::
In the following network, the switch is closed at t = 0- and the sampling starts from t = 0. The sampling frequency is 10Hz.
[1] The samples x (n) (n = 0, 1, 2, ...) are given by [2 marks]
(A) 5(1- e-0.05n)
(B) 5e-0.05n
(C) 5(1- e-5n)
(D) 5e-5n[2] The expression and the region of convergence of the z-transform of the sampled signal are [2 marks]
(A) 5z/(z-e-5), |z| < e-5
(B) 5z/(z-e-0.05), |z| < e-0.05
(C) 5z/(z-e-0.05), |z| > e-0.05
(D) 5z/(z-e-5), |z| > e-5asked in Electronics and Communication Engineering, 2008
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5.
Statement for Linked Answer Questions::
A two-port network shown below is excited by external dc sources. The voltages and the currents are measured with voltmeters V1, V2 and ammeter A1, A2 (all assumed to be ideal), as indicated. Under following switch conditions, the readings obtained are:
i). S1- Open, S2-Closed, A1=0A, V1=4.5V, V2=1.5V, A2=1A
ii). S1- Closed, S2-Open, A1=4A, V1=6V, V2=6V, A2=0A
[1] The z-parameter matrix for this network is [2 marks] 
[2] The h-parameter matrix for this network is [2 marks] 
asked in Electronics and Communication Engineering, 2008
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6.
The following series RLC circuit with zero initial conditions is excited by a unit impulse function δ(t).
[1] For t > 0, the output voltage Vc(t) is [2 marks] 
[2] For t > 0, the voltage across the resistor is [2 marks] 
asked in Electronics and Communication Engineering, 2008
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