ISRO Scientist/Engineer ECE Solved Papers
Practice previous years' questions for Electromagnetics, Antennas, Microwave Engineering, Digital Communication, Signals & Systems, Analog Electronics, VLSI, and Optical Communications.
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Marking scheme: +3.00 positive, -0.75 negative (ICRB Standard).
Two systems $h_1[n] = A(b_1)^n u[n]$ and $h_2[n] = A(b_2)^n u[n]$ are cascaded. If the effective $H(z) = \frac{4}{4 - z^{-2}}$, find a possible value of $(A, b_1, b_2)$:
The inputs to a digital circuit are signals A, B and C. $\overline{A}$, $\overline{B}$ and $\overline{C}$ are not available. The $+5\text{V}$ supply and the ground can be used as logic '1' and '0' inputs respectively. To implement a function $\overline{B}\,\overline{C} + A\overline{C}$ using only 2:1 multiplexer, minimum number of MUX required is:
Which of the following is not true in VHDL?
A 4 bit unipolar DAC with 10V reference is fed to the input of a comparator, whose threshold is set as 7.5V. When the DAC counts from 0 and reaches 8, the comparator showed threshold crossing wrongly. It is found that one of the DAC input bit is stuck at '1'. Which is the stuck at '1' bit?
Resistors R1, R2 and R3 are connected in series across a voltage source 'V' and R4 is connected in parallel with R3. R1 to R4 are to be chosen from available resistor values 3 Ω, 6 Ω, 10 Ω and 15 Ω. What will be the ratio of maximum current to minimum current through R1 by choosing resistor values appropriately?
A system is defined by the difference equation:
$$y(n) = 1.8y(n - 1) - 0.72y(n - 2) + x(n) + 0.5x(n - 1)$$then the system is
The state transition diagram for the diagram given is:
Given a single 3:8 active high output decoder. What is the minimum number of 3-input OR gates required to implement a one bit Full adder?
In the given figure, find the value of $(X_0, X_1, X_2, X_3, X_4, X_5, X_6, X_7)$ to realise the function $F = A + \overline{B}$
Which of the following is True for signal travelling through a Wave-Guide?
For matched junction S parameters, which of the following is correct?
Which of the following transmission modes is supported by Stripline?
For a directional coupler, if $P_i = \text{Incident Power}$, $P_o = \text{Output power}$, $P_f = \text{Forward coupled power}$ and $P_r = \text{Reverse coupled power}$; then, Directivity of directional coupler is
Magic Tee can produce
The cut off frequency of TEM wave is
In transistor oscillators, FET and BJT are used. Instability is achieved by:
In a three stage cascade amplifier, each stage has a gain of 10 dB and noise figure of 10 dB. The overall noise figure is
Operating Frequency limitation for Bipolar semi-conductor device is due to a
Which of the following offers highest speed of operation?
Gunn Diode operated at a high frequency is a
Compared to Silicon, GaAs Semi-conductors offer advantage of
Calculate the approximate power added efficiency of following power amplifier:
- DC Voltage: 8 volts
- DC Current: 5 Amp
- AC Input signal: 0 dBm
- O/P power: 30 dBm
Which of following class of amplifiers provides highest efficiency?
Compared to Linear power supplies SMPS offers
What are the different circuit topologies used for DC/DC converter designs?