Practice previous years' questions for Electromagnetics, Antennas, Microwave Engineering, Digital Communication, Signals & Systems, Analog Electronics, VLSI, and Optical Communications.
Marking scheme: +3.00 positive, -0.75 negative (ICRB Standard).
For identical total transmitted power, the ratio of $S/N$ for wide band FM to $S/N$ of DSB-AM (with $m_a=1$) is :
(Given $f_m = 15\text{ KHz}$ & frequency deviation $= \pm 75\text{ KHz}$)
A signal $m(t)=3\cos(6000\pi t)+4\cos(7000\pi t)+5\cos(10000\pi t)$ is to be sampled. What is the minimum sampling rate for band pass sampling for truthful representation :
Minimum number of bits required to represent maximum value of given analogue signal with 0.1% accuracy is :
An Ideal power limited communication channel with additive white Gaussian noise is having 4 KHz bandwidth and Signal to Noise ratio of 255. The channel capacity is :
An Ideal power limited communication channel with additive white Gaussian noise with 1 MHz bandwidth and Signal to Noise ratio of 15 is transmitting the information at theoretical maximum rate. If the Signal to Noise ratio is reduced to 7, how much bandwidth is required to maintain same rate :
Following constellation diagram represents :
The information rate to be transmitted is $900\text{ bits/sec}$, FEC is $3/4$, the symbol rate for QPSK modulation scheme is :
Electric displacement density D at any point on spherical surface of radius R with a charge Q at the centre in a medium with dielectric constant $\epsilon$ is :
Which of the following does not represent Maxwell's Equation :
For a homogeneous and isotropic medium with a charge density ρ & dielectric constant ε, the Poisson's equation for electrical potential V is :
For a plane travelling EM wave, the correct equation for characteristic impedance Z for the medium with permittivity of $\epsilon$ and permeability of $\mu$ is :
A plane wave propagating in the dielectric medium has an electric field given as $E_x = E_0 \cos(2.6 \times 10^{10}t - 100z)$. The phase velocity of plane wave is :
A plane wave propagating in the dielectric medium has an electric field given as $E_x = E_0 \cos(3 \times 10^{10}t - 100z)$. The dielectric constant of the medium is :
A transmission line of 50 Ω characteristic impedance terminated by a load impedance of $50 - j50$. The magnitude of reflection coefficient at the load is :
The outer conductor diameter and the inner conductor diameter dimensions of a coaxial cable are made twice to its original value. (Coaxial line is filled with dielectric material having dielectric constant $\epsilon_r = 4.0$). The correct statement is :
A non dispersive media has:
A plane wave is characterized by :
$$\tilde{E} = \left(0.5\hat{x} + \hat{y} e^{-j\pi/2}\right) e^{j\omega t - jkz}$$
The wave is :
If a right hand circularly polarised wave is incident on a perfect conductor. The reflected wave is :
In which of the following cases the divergence of electric field is zero :
Skin depth at 2 GHz for a gold conductor with $\sigma = 4.55 \times 10^7\text{ S/m}$ is $1.5\;\mu\text{m}$. Skin depth (in $\mu\text{m}$) at 8 GHz & 18 GHz is :
The S matrix of a lossless line having length $\lambda/4$ is :
In the following Smith Chart,
the movement from y along a constant VSWR circle to y1 needs addition of :
If the RF transmission is terminated in its Characteristic impedance $Z_0$ which of the following statements is wrong :
The loss-less, quarter wavelength long, RF transmission of characteristic impedance 50 Ω is terminated in pure resistive load impedance 100 Ω, the input impedance is :
A lossless matching circuit is shown in the figure
The values satisfying the matching condition are :