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The signal m(t) as shown is applied both to a phase modulator (with kp as the phase constant) and a frequency modulator with (kf as the frequency constant) having the same carrier frequency. The ratio $$\frac{kp}{kf}$$ $$(in \frac{rad}{Hz})$$ for the same maximum phase deviation is
A message m(t) bandlimited to the frequency fm has a power of Pm. The power of the output signal in the figure is
The input x(t) and output y(t) of a system are related as $$y(t)=\int_{-\infty}^{t} x(t) \cos(4t) dt$$ The system is
Consider a system shown in the figure. Let X(f ) and Y(f ) denote the Fourier transforms of x(t) and y(t) respectively. The ideal HPF has the cut-off frequency 10 KHz.
The positive frequencies where Y(f ) has spectral peaks are
Let $$x(t)=rect(t-\frac{1}{2})$$ where $$rect(t) = 1$$ for $$\frac{-1}{2} \leq t \leq \frac{1}{2}$$ and Zero otherwise , then the Fourier Transform of $$x(t) + x(-t)$$ will be given by
A signal $$x(t) = sinc (\alpha t)$$, where $$\alpha$$ is a real constant, is the input to a Linear Time Invariant system whose impulse response is $$h(t) = sinc (\beta t)$$, where $$\beta$$ is a real constant. If min($$\alpha, \beta$$) denotes the minimum of $$\alpha$$ and $$\beta$$ and similarly, max($$\alpha, \beta$$) denotes the maximum of $$\alpha$$ and $$\beta$$ and K is a constant, which one of the following statements is true about the (here, $$sinc = \frac{\sin(\pi x)}{\pi x}$$) output of the system?
A message signal given by $$m(t)=\frac{1}{2} \cos (\omega_{1} t)-(\frac{1}{2}) \sin (\omega_{2} t)$$ is amplitude modulated with a carrier of frequency $$\omega_{c}$$ to generates $$s(t) = [1 + m(t)] \cos( \omega_{c}t)$$.What is the power efficiency achieved by this modulation scheme?
If $$E_{b}$$, the energy per bit of a binary digital signal, is $$10^{-5}$$ Ws(watt-Second) and the one-sided power spectral density of the white noise, $$N_{o}=10^{-6} \frac{W}{Hz}$$ then the output SNR of the matched filter is
At a given probability of error, binary coherent FSK is inferior to binary coherent PSK by.
If $$z_{0}$$ is a zero of a (real-valued) linear-phase FIR filter then following is/are also zero/zeros of a (real-valued) linear-phase FIR filter,
What will be the minimum numbers of tap require to realize a FIR filter having $$f_{pass}$$ = 10 kHz and $$f_{stop}$$ =15 kHz, 0.1 dB pass band ripple and 60 dB attenuation in stop band. Sampling frequency is 200 kHz.
The system with the transfer function $$\frac{Y(s)}{X(s)}=\frac{s}{s+p}$$ has an output $$y(t) = \cos \left(2t - \frac{\pi}{3}\right)$$ for the input signal $$x(t) = p \cos \left(2t - \frac{\pi}{2}\right)$$.Then the system parameter p is
The approximate Bode magnitude plot of a minimum-phase system is shown in the figure below. The transfer function of the system is
For the circuit of the figure the inductor current $$i_{L}$$ just before t = 0 is
The network shown in below figure consist of two coupled coils and a capacitor. At t=0 = 0, the switch is closed connecting a voltage generator, $$v_{in} = V \sin(\frac{t}{\sqrt{MC}})$$ what will be the value of $$\frac{d v_{a}}{dt} (0+)$$?
In the network shown below, switch is moved from position a to b at t = 0 . The current $$i_{L} (t)$$ for t>o is given as
The voltage gain $$\frac{v_{out}}{v_{in}}$$ of a circuit shown below is zero. If $$\omega =333.33 rad/s$$ , the value of c is
In the network shown below, switch is opened at t = 0 after long time. The current $$i_{L} (t)$$ for $$t > 0$$ is given as
The Q factor of a RLC circuit is 5 at its resonance frequency of 1 kHz. Find the bandwidth of the circuit
For the circuit shown in figure, find the frequency at which this circuit will be at resonance
What is the power loss in the 10 Ω resistor in the Network shown in figure?
The voltmeter in the circuit shown in the figure is ideal. The transformer has two identical windings with perfect coupling. The reading on the voltmeter will be
The Theveαnin’s equivalent circuit of the network shown in figure is across a-b is
The average power consumed by the following circuit is
$$V_{rms} = 20 \angle 53.13^\circ V$$
The given figure shows the pole zero pattern of a filter in the S-plane. The Filter in question is a
Output voltage $$V_{0}$$ of the circuit shown in figure below. (The input voltages are $$V_{1}=2.5 V and V_{2} =1 V)$$
With out any additional circuitry an 8:1 MUX can be used to obtain
The circuit shown in the figure converts
The following CMOS transistor based circuit with A, B, C as input and X, Y as output represents which circuit?
Minimum number of complementary CMOS transistors pair will be required to implement function, $$F =ABC+\overline{(A+B+C)}$$ are
The CMOS circuit shown below implements the function
If input to T flip flop is 200 Hz signal, then what will be the output signal frequency if four T flip flops are connected in cascade
Simplify the below function represented in sum of minterms $$F(A, B, C, D, E) = \sum (0 ,1 ,2 ,3,8 ,9, 16, 17, 20, 21, 24, 25, 28, 29, 30, 31)$$
All transistor in the N output current mirror in figure given below are matched with a finite gain $$\beta$$ and early voltage $$V_{A} = \infty$$ . The expression for load current is
Class C amplifier operates
A particular amplifier circuit used for frequency doubling is.
The configuration of given figure is a
For current flowing through semi-conductor, which of the following statement is true
Which of the following statement is true for Programmable Logic array(PLA)?
When transistors are used in digital circuits they usually operate in the:
Two initially identical samples A & B of pure germanium are doped with donors to concentrations of $$1 \times 10^{20}$$ and $$3 \times 10^{20}$$ respectively. If the hole concentration in A is $$9 \times 10^{12}$$ then the hole concentration in B at the same temperature will be
The built in potential (diffusion potential) in a p-n junction
Transistors $$Q_{1}$$ and $$Q_{2}$$ are identical and $$\beta >> 1$$ in the circuit shown in the figure below. The output voltage is $$(V_t = 0.026 V)$$:
Consider following 8085 microprocessor program
MVI A, DATA1
ORA A
JM DISPLAY
OUT PORT1
CMA
DISPLAY : ADI 01H
OT PORT1
HLT
If DATA1 = A7H, the output at PORT1 is
From the figure,obtain state equation
In an ADC, the minimum Effective Number of Bits (ENOB) requires to represent each quantization level to achieve Signal to Noise and Distortion Ratio (SINAD) of 70 dB is
Two isotropic antennas are separated by a distance of two wavelengths. If both the antennas are fed with currents of equal phase and magnitude, the number of lobes in the radiation pattern in the horizontal plane are
The half-power beam width (HPBW) of an antenna in the two orthogonal planes are $$120^\circ$$ and $$40^\circ$$ respectively. The directivity of the antenna is approximately equals to
Two resistors $$R_{1}$$ and $$R_{2}$$ (in ohms) at temperatures $$T_{1} K_{1}$$ and $$T_{2} K_{2} $$respectively, are connected in series. Their equivalent noise temperature is
The Gray code for $$(A5)_{16}$$ is equivalent to
In Direct Broadcast System (DBS),
If analog sampling frequency of a band limited signal is doubled then corresponding digital sampling frequency will be
In communication system, if for a given rate of information transmission requires channel bandwidth, $$B_{1}$$ and signal-to-noise ratio $$SNR_{1}$$ If the channel bandwidth is doubled for same rate of information then new signal-to-noise ratio will be
Output SNR of a 10 bit PCM was found to be 30 dB, desired SNR is 42 dB. To achieve desired SNR by increasing the number of quantization levels, then new levels will be
Let Y(k) be the 5-point DFT of the sequence y(n) = {1 2 3 4 5}. What is the 5-point DFT of the sequence Y(k) ?
Let A be the series $$\sum_{n=1}^{\infty} \frac{(-1)^{n}}{\log(n+2)}$$ and B be the series $$\sum_{n=2}^{\infty} \left(\frac{3n-4}{3k+2}\right)^{\left(\frac{n+1}{3}\right)}$$ for real numbers. Then which of the following is true.
A test has 5 multiple-choice questions. Each question has 4 answer options (A, B, C, D). What is the probability that a student will choose “B” for at least three questions if
he/she leaves no questions blank?
The DTFT of a sequence x[n] is given by $$X(e^{j \omega})$$.since $$X(e^{j \omega})$$ is period function of $$\omega$$,it can be expressed classical Fourier series as $$X(e^{j \omega})= \sum_{n=-\infty}^\infty c_{n} e^{jn \omega_{o} \omega}$$ where $$\omega_{o}$$ is a fundamental frequency. Which of the following statement is correct?
Evaluate $$\int_{0}^{1}\frac{ \ln(x+1)}{x^{2}+1}$$
Fourier transform of a real and odd function is
Let F(w) be the Fourier Transform of a function f(t). The F(0) is
Laplace transform of $$e^{-at} f(t)$$
A monochromatic plane wave of wavelength 500 µm is propagating in the direction as shown in the figure below. $$\overrightarrow{E_{i} } ,\overrightarrow{E_{r}} , \overrightarrow{E_{t}}$$ denotes incident, reflected and transmitted electric field vectors associated with the wave. The expression for $$\overrightarrow{E_{t}}$$ and $$\overrightarrow{E_{r}}$$ are
Indicate which one of the following modes do NOT exist in a rectangular resonant cavity
A long solenoid of radius R, having N turns per unit length carries a time dependent current $$I(t)=I_{0} \sin (\omega t)$$. The magnitude of induced electric field at a distance $$\frac{R}{2}$$ radially from the axis of the solenoid is
Penetration depth of magnetic field inside a superconductor is
A parallel plate air-filled capacitor has plate area of $$10^{-4} m^{2}$$ and plate separation of $$10^{-3}$$. It is connected to a 2 V, 1.8 GHz source. The magnitude of the displacement current is $$\epsilon_{o}= \frac{1}{36 \pi \times 10^{-9} \frac{F}{m}}$$
Two rectangular waveguide have dimensions of $$1 cm \times 0.5 cm$$ and $$1 cm \times 0.25 cm$$ respectively. Their respective cut-off frequencies will be
Which of the following has the highest skin depth?
The electric field vector of a wave is given as $$\overrightarrow{E}=E_{o} e^{j(\omega t + 3x - 4y)}\frac{8\overrightarrow{a_{x}}+6\overrightarrow{a_{y}}+5\overrightarrow{a_{z}}}{\sqrt{125}} V/m$$. Its frequency is 10 GHz. The phase velocity in Y-direction will be
The electric field of a plane wave propagating in a lossless non-magnetic medium is given by the following equation $$\overrightarrow{E} (Z,t)= \cos (2 \pi \times 10^{9} t+\beta Z)\hat{a_{x}}+2 \cos (2 \pi \times 10^{9} t +\beta Z+\frac{\pi}{2}) \hat{a_{y}}$$ The type of wave polarization is
A ring of radius R carries a linear charge density $$\lambda$$ . It is rotating with angular speed $$\omega$$ . The magnetic field at its center is
A transmission line with a characteristic impedance of 100 Ω is used to match a 50 Ω section to a 200 Ω section. If the matching is to be done both at 500 MHz and 1.2 GHz, the length of the transmission line can be approximately,
System has some poles lying on imaginary axis is
The open-loop DC gain of a unity negative feedback system with closed loop transfer function $$\frac{(S+4)}{(S2+7S+13)}$$ is
The unit impulse response of a system is h(t)=e^{-t}, t>0 For this system, the steady-state value of the output for unit step input is equal to
A system has fourteen poles and two zeros. Its high frequency asymptote in its magnitude plot having a slope of
Consider a unity feedback system having an open loop transfer function $$G(j \omega)=\frac{K}{j \omega(j0.2 \omega +1)(j0.05 \omega+1)}$$ Find open loop gain (k) with gain margin of 20 dB
The open loop transfer function of a unity feedback system is G(S)=$$\frac{K}{S(S^{2}+S+2)(S+3)}$$ The range of K for which the system is stable is
For the CE (Common emitter) circuit shown, what will be the value of $$I_{E}$$ and $$V_{CE}$$?
Educational materials for CAT preparation
