Q. Consider a white Gaussian noise process 𝑁(𝑡) with two-sided power spectral density 𝑆𝑁 (𝑓) = 0.5 W/Hz as input to a filter with impulse response 0.5𝑒−𝑡2/2 (where 𝑡 is in seconds) resulting in output 𝑌(𝑡). The power in 𝑌(𝑡) in watts is (A) 0.11 (B) 0.22 (C) 0.33 (D) 0.44 Ans: 0.22
Consider a white Gaussian noise process 𝑁(𝑡) with two-sided power spectral density 𝑆𝑁 Read More »
Q. The circuit shown in the figure is used to provide regulated voltage (5 V) across the 1 kW resistor. Assume that the Zener diode has a constant reverse breakdown voltage for a current range, starting from a minimum required Zener current, IZ min = 2 mA to its maximum allowable current. The input voltage VI
Q. A lossy transmission line has resistance per unit length R = 0.05 W/ m. The line is distortionless and has characteristic impedance of 50W . The attenuation constant (in Np/m, correct to three decimal places) of the line is . Ans: 0.001 Sol:
A lossy transmission line has resistance per unit length R = 0.05 W/ m Read More »
Q. There are two photolithography systems: one with light source of wavelength λ1 = 156 nm (System 1) and another with light source of wavelength λ2 = 325 nm (System 2). Both photolithography systems are otherwise identical. If the minimum feature sizes that can be realized using System1 and System2 are Lmin1 and Lmin2 respectively,
Q. A traffic signal cycles from GREEN to YELLOW, YELLOW to RED and RED to GREEN. In each cycle, GREEN is turned on for 70 seconds, YELLOW is turned on for 5 seconds and the RED is turned on for 75 seconds. This traffic light has to be implemented using a finite state machine (FSM).
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
A binary source generates symbols 𝑋 ∈ {−1,1} which are transmitted over a noisy channel Read More »
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
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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
Consider the following amplitude modulated signal Read More »
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
