Recent questions without answers

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761
The $\text{ACF}$ of a rectangular pulse of duration $\mathrm{T}$ isa rectangular pulse of duration $\mathrm{T}$a rectangular pulse of duration $\mathrm{2T}$a triangular p...
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762
The image channel selectivity of superheterodyne receiver depends upon$\text{IF}$ amplifiers only$\text{RF}$ and $\text{IF}$ amplifiers onlyPreselector, $\text{RF}$ and $...
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763
In a $\text{PCM}$ system with uniform quantisation, increasing the number of bits from $8$ to $9$ will reduce the quantisation noise power by a factor of$9$$8$$4$$2$
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764
The Fourier transform of a function $x(t)$ is $\mathrm{X}(f)$. The Fourier transform of $\frac{d \mathrm{X}(f)}{d f}$ will be$\frac{dX(f)}{d f}$$j 2 \pi f X(f)$$jf X(f)$$...
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765
Flat top sampling of low pass signalsgives rise to aperture effectimplies oversamplingleads to aliasingintroduces delay distortion
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766
A $\text{DSB-SC}$ signal is generated using the carrier $\cos \left(\omega_{c}, t+\theta\right)$ and modulating signal $x(t)$. The envelope of the $\text{DSB-SC}$ signal ...
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767
Quadrature multiplexing isthe same as $\text{FDM}$the same as $\text{TDM}$a combination of $\text{FDM}$ and $\text{TDM}$quite different from $\text{FDM}$ and $\text{TDM}$...
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768
The Fourier transform of a voltage signal $x(t)$ is $X(f)$. The unit of $|X(f)|$ isvoltvolt-secvolt/secvolt $^{2}$
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769
Compression in $\text{PCM}$ refers to relative compression ofhigher signal amplitudeslower signal amplitudeslower signal frequencieshigher signal frequencies
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770
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771
The spectral density of a real valued random process hasan even symmetryan odd symmetrya conjugate symmetryno symmetry
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772
The probability density function of the envelope of narrow band Gaussian noise isPoissonGaussianRayleighRician
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773
The intrinsic impedance of copper at high frequencies ispurely resistivepurely inductivecomplex with a capacitive componentcomplex with an inductive component
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774
The Maxwell equation $\mathrm{V} \times \mathrm{H}=\mathrm{J}+\frac{\partial \overline{D}}{\partial t}$ is based onAmpere's lawGauss' lawFaraday's lawCoulomb's law
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775
All transmission line sections shown in the figure is have a characteristic impedance $\text{R}_{0}+\text{j}_{0}$. The input impedance $\text{Z}_{\text {in}}$ equals$\fra...
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776
The time averages Poynting vector, in $W / m^{2}$, for a wave with $\vec{E}=24 \; e^{} \; a_{} \mathrm{~V} / \mathrm{m}$ in free space is$ – \frac{2.4}{\pi} \vec{a}_{z}...
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777
The wavelength of a wave with propagation constant $(0.1 \pi+j 0.2 \pi) \mathrm{m}^{-1}$ is$\frac{2}{\sqrt{0.05}} \mathrm{~m}$$10 \mathrm{~m}$$20 \mathrm{~m}$$30 \mathrm{...
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778
The depth of penetration of wave in a lossy dielectric increases with increasingconductivitypermeabilitywavelengthpermittivity
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779
The polarisation of wave with electric field vector$\overrightarrow{\mathrm{E}}=\mathrm{E}_{0} \; e^{j(\hat{\rho}(\omega t+\beta z)}\left(\vec{a}_{x}+\vec{a}_{y}\right)$ ...
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780
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781
The radiation resistance of a circular loop of one turn is $0.01 \; \Omega$. The radiation resistance of five turns of such a loop will be$0.002 \; \Omega$$0.01 \; \Omega...
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782
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783
The maximum usable frequency of an ionospheric layer at $60^{\circ}$ incidence and with $8 \; \mathrm{mHz}$ critical frequency is$16 \; \mathrm{MHz}$$\frac{16}{\sqrt{3}} ...
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784
A loop is rotating about the $y$-axis in a magnetic field $\overrightarrow{\mathrm{E}}=\mathrm{B}_{0} \cos (\omega t+\phi) \vec{a}_{x} \mathrm{~T}$. The voltage in the lo...
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785
The far field of an antenna varies with distance $\mathrm{r}$ as$\frac{1}{r}$$\frac{1}{r^{2}}$$\frac{1}{r^{3}}$$\frac{1}{\sqrt{r}}$
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786
Determine the frequency of resonance and the resonant impedance of the parallel circuit shown in the figure is. What happens when $\text{L}=\mathrm{CR}^{2}$ ?
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788
Draw the transfer characteristic of the circuit of the figure assuming both $D_{1}$ and $D_{2}$ to be ideal.How would the characteristic change if $D_{2}$ is ideal, but $...
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789
Given an irrotational vector field$\overrightarrow{\mathrm{F}}=(k 1 x y+k 2) \vec{a}_{x}+\left(3 x 2-k 3 Z) \vec{a}_{y}+(3 x z 2-y) \vec{a}_{z}\right.$Find $V . \vec{F}$ ...
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790
The loop transfer function of a single loop control system is given by\[\mathrm{G}(\mathrm{s}) \mathrm{H}(\mathrm{s})=\frac{100}{s(1+0.01 s)} e^{-s \mathrm{T}}\]Using the...
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791
The characteristic equation of a feedback control system is\[s^{4}+20 s^{3}+15 s^{2}+2 s+K=0\]Determine the range of $K$ for the system to be stable.Can the system be mar...
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792
Draw a signal flow graph for the following set of algebraic equations\[\begin{array}{l}y_{2}=a \; y_{1}-g \; y_{3} \\y_{3}=e \; y_{2}+c \; y_{4} \\y_{4}=b \; y_{2}-d \; y...
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793
Consider the system shown in the figure is. Determine the value of a such that the damping ratio is $0.5$. Also obtain the values of the rise time $t_{r}$ and maximum ove...
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794
Determine the input impedance of the given and investigatie if it can be inductive.
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795
Find the value of $R^{\prime}$ in the circuit of the figure is for generating sinusoidal oscillations. Find the frequency of oscillations.
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796
In the circuit of the figure is determine the resistance $R_{0}$ seen by the output terminals. Ignore the effects of $R_{1}$ and $R_{2}$.
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797
The $\text{JFET}$ in the circuit of the figure is characterised by the parameters $\mathrm{I}_{\mathrm{DSS}}=4 \; \mathrm{MA}$ and $\mathrm{V}_{p}=-4 \mathrm{V}$.Find$\ma...
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799
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800
Write a short assembly language program, without using any arithmetic instruction, to store hexadecimal $5D$ in the flag register of $8085$ microprocessor. Data in other ...