Q1.The far-zone power density radiated by a helical antenna is approximated as:
The radiated power density is symmetrical with respect to ϕ and exists only in the upper
hemisphere: C0 is a constant. The power radiated by the antenna (in
watts) and the maximum directivity of the antenna, respectively, are
Answer : Option BExplaination / Solution: No Explaination.
Q2.Which one of the following is an eigen function of the class of all continuous-time, linear, time-invariant systems u(t) denotes the unit-step function)?
Answer : Option CExplaination / Solution: No Explaination.
Q3.A continuous-time function x(t) is periodic with period T. The function is sampled uniformly
with a sampling period TS. In which one of the following cases is the sampled signal periodic?
Q4.Match the inferences X, Y, and Z, about a system, to the corresponding properties of the elements of first column in Routh‟s Table of the system characteristic equation
X: The system is stable … P: … when all elements are positive
Y: The system is unstable … Q: … when any one element is zero
Z: The test breaks down … R: … when there is a change in sign of coefficients
Answer : Option DExplaination / Solution: No Explaination.
Q5.A first-order low-pass filter of time constant T is excited with different input signals (with zero
initial conditions up to t = 0). Match the excitation signals X, Y, Z with the corresponding time
responses for t ≥ 0:
X: Impulse P: 1 – e-t/T
Y: Unit step Q: t – T(1 – e(-t/T)
Z :Ramp R: e-t/T
Answer : Option CExplaination / Solution:
In general the first order, L.P.F filter transfer function is because G(0) = k and G(∞) = ∞ if we take this transfer function as reference and give different input such as
s(t).r(t).u(t)
Q7.A network consisting of a finite number of linear resistor (R), inductor (L), and capacitor (C)
elements, connected all in series or all in parallel, is excited with a source of the form
The source has nonzero impedance. Which one of the following is a possible form of the
output measured across a resistor in the network?
Answer : Option AExplaination / Solution:
The property of any LTI system or network is if the excitation contains „n‟ number of different
frequency then the response also contains exactly n number of different frequency term and the
output frequency and input frequency must be same however depending on components there
is a possible change in amplitude and phase but never the frequency.
⟶ If the source has 3 frequency terms as given then any voltage or any current of any element should have also 3 terms based on this option (B) and (D) are eliminated.
⟶ If we take option (C). It has 3 frequency term but it also suggest there is a phase change so ϕk but amplitude must be same as input as ak is present which may not be true always.
⟶ So option (A) is correct, as it suggest frequency term of output and inputs are same with
possible change in amplitude and phase, because we have (bk and ϕk ).
Q9.The functionality implemented by the circuit below is
Answer : Option BExplaination / Solution:
Decoder inputs will behaves as MUX select lines and when the output of decoder is high then only corresponding buffer will be enable and passed the inputs (P,Q,R,S) to the outpuut line, so it will work as 4-to-1 multiplexer.
Q10.In an 8085 system, a PUSH operation requires more clock cycles than a POP operation. Which one of the following options is the correct reason for this?