ISRO Scientist/Engineer CS Solved Papers

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 :

The true statement for wave propagation in rectangular wave guides filled with air is :

As the wave frequency approaches to cut-off frequency of wave guide, the correct statement is :

The EM wave which does not propagate through a rectangular waveguide with $a = 30\text{ mm}$ & $b = 15\text{ mm}$ is :

The minimum input signal that gives output signal to noise ratio of 10 dB in a system that has an input impedance equal to 50 Ω, a noise figure of 4 dB and bandwidth of 100 KHz is :
[$10 \log_{10}(kT_0) = -174\text{ dBm}$]

In this circuit,

$V_{\text{out}}$ is :

The RF amplifier A is having 3 dB NF & 5 dB of gain, amplifier B is having 3.5 dB NF & 15 dB. For overall noise figure of the cascaded system, the correct statement is :