Q. A p-n step junction diode with a contact potential of 0.65 V has a depletion width of 1μm at equilibrium. The forward voltage (in volts, correct to two decimal places) at which this width reduces to 0.6 μm is  Ans: 0.40 – 0.43

Q. A binary source generates symbols 𝑋 ∈ {−1,1} which are transmitted over a noisy channel. The probability of transmitting 𝑋 = 1 is 0.5. Input to the threshold detector is 𝑅 = 𝑋 + 𝑁. The probability density function 𝑓𝑁(𝑛) of the noise 𝑁 is shown below. If the detection threshold is zero, then

Q. Consider a binary channel code in which each codeword has a fixed length of 5 bits. The Hamming distance between any pair of distinct codewords in this code is at least 2. The maximum number of codewords such a code can contain is  Ans: 16

Q. Consider the following amplitude modulated signal: 𝑠(𝑡) = cos(2000 𝜋𝑡) + 4 cos(2400 𝜋𝑡) + cos(2800 𝜋𝑡). The ratio (accurate to three decimal places) of the power of the message signal to the power of the carrier signal is   Ans: 0.125

Q. A discrete-time all-pass system has two of its poles at 0.25∠0° and 2 ∠30° Which one of the following statements about the system is TRUE? A. It has two more poles at 0.5Ð30and 4Ð0 . B. It is stable only when the impulse response is two-sided. C. It has constant phase response over all

Q. Let M be a real 4×4 matrix. Consider the following statements: S1: M has 4 linearly independent eigenvectors. S2: M has 4 distinct eigenvalues. S3: M is non-singular (invertible). Which one among the following is TRUE? (A) S1 implies S2                                          (B) S1 implies S3 (C) S2 implies S1                                          (D) S3 implies S2 Ans: S2

Q. The points P, Q, and R shown on the Smith chart (normalized impedance chart) in the following figure represent: A. P: Open Circuit, Q: Short Circuit, R: Matched Load B. P: Open Circuit, Q: Matched Load, R: Short Circuit C. P: Short Circuit, Q: Matched Load, R: Open Circuit D. P: Short Circuit, Q:

Q. A function 𝐹(𝐴, 𝐵, 𝐶) defined by three Boolean variables A, B and C when expressed as sum of products is given by 𝐹 = 𝐴̅ ⋅ 𝐵̅ ⋅ 𝐶̅ + 𝐴̅ ⋅ 𝐵 ⋅ 𝐶̅ + 𝐴 ⋅ 𝐵̅ ⋅ 𝐶̅ where, 𝐴̅, 𝐵̅, and 𝐶̅ are the complements of the respective variables.

Q. The logic function f (X , Y) realized by the given circuit is (A) NOR                      (B) AND                     (C) NAND                   (D) XOR Ans: XOR

Q. In a p-n junction diode at equilibrium, which one of the following statements is NOT TRUE? A. The hole and electron diffusion current components are in the same direction. B. The hole and electron drift current components are in the same direction. C. On an average, holes and electrons drift in opposite direction. D.