Three identical RC-Coupled transistor amplifiers are cascaded. If each of the amplifiers has a frequency response as shown in figure, the overall frequency response is as given as

Consider the following statements in connection with the CMOS inverter in the Figure. Where both the MOSFETS are of enhancement type and both have a threshold voltage of 2V.

Statement 1: T₁ conducts when V_i $$ \ge \,2\,V$$.
Statement 2: T₁ is always in saturation when $${V_0}\, = \,0\,V$$.

Which of the following is correct?

The circuit in the figure employs positive Feedback and is intended to generate sinusoidal oscillation. If at a frequency f$$_0$$, B(f)= $${{\Delta {V_f}(f)} \over {{V_0}(f)}} = {1 \over 6}\,\,\angle {0^0}$$ then to sustain oscillation at this frequency.

In a negative feedback amplifier using voltage - Series (i.e., voltage - sampling, series mixing) feedback

If the variance $$\sigma _d^2$$ of d(n) = x(n - 1) is one-tenth the variance $$\sigma _x^2$$ of a stationary zero-mean discrete-time signal x(n), then the normalized autocorrelation function $${R_{xx}}\,(k)\,/\,\,\sigma _x^2\,at\,\,k\,\, = \,1$$ is

For a bit-rate of 8 kbps, the best possible values of the transmitted frequencies in a coherent binary FSK system are

A 1 MHz sinusoidal carrier is amplitude modulated by a symmetrical square wave of period 100 µsec. Which of the following frequencies will NOT be present in the modulated signal?

The transfer function of a system is $$G\left(s\right)\;=\;\frac{100}{\left(s\;+\;1\right)\left(s\;+\;100\right)}$$.For a unit step input to the system the approximate settling time for 2% criterion is

The system shown in Figure remains stable when

The characteristic polynomial of a system is
q(s) = 2s⁵ + s⁴ + 4s³ + 2s² + 2s + 1. The system is

Which of the following points is NOT on the root locus of a system with the open loop transfer function $$$G\left(s\right)H\left(s\right)=\frac K{s(s+1)(s+3)}$$$

Consider a system with the transfer function $$$G\left(s\right)=\frac{s+6}{Ks^2+s+6}$$$ Its damping ratio will be 0.5 when the value of K is

The phase margin of a system with the open-loop transfer function G(s)H(s)=$${{(1 - s)} \over {(1 + s)(2 + s)}}$$ is?

The system with the open loop transfer function G(s)H(s)=$${1 \over {s\left( {{s^2} + s + 1} \right)}},$$ has a gain margin of

The Nyquist plot of an all-pole second order open-loop system is shown in Figure. Obtain the transfer function of the system.

A unity feedback system has the plant transfer function G_p(s)=$${1 \over {\left( {s + 1} \right)\left( {2s + 1} \right)}}$$
(a) Determine the frequency at which the plant has a phase lah of 90^o.
(b) An intergral controller with transfer function G_c(s)=$${k \over s}$$ , isplaced in the forwardpath the value of k such that the compensated system has an open loop gain margin of 2.5.
(c) Determine the steady state errors of the compensated system to unit-step and unit-ramp inputs.

The transfer function Y(s)/U(s) of a system described by the state equations
$$\mathop x\limits^ \bullet $$(t) = -2x(t)+2u(t)
y(t) = 0.5x(t) is

The block diagram of a linear time invariant system is given in Figure is (a) Write down the state variable equations for the system in matrix form assuming the state vector to be $${\left[ {{x_1}\left( t \right)\,\,{x_2}\left( t \right)} \right]^T}$$
(b) Find out the state transition matrix.
(c) Determine y(t), t ≥ 0, when the initial values of the state at time t = 0 are $${x_1}$$(0) = 1, and $${x_2}$$(0) = 1.

The number of comparators required in a 3-bit comparator type ADC is

It is required to design a binary mod-5 synchronus counter using AB flip-flops such that the output Q₂Q₁Q₀ changes as $$000 \to 001 \to 010$$ ........and so on. The excitation table for the AB flip-flops is given in the table

(a) Write down the state table for the mod-5 counter.
(b)Obtain simplified SOP expressions for the inputs A₂, B₂, A₁, B₁, A₀ and B₀ in terms of Q₂, Q₁, Q and their complements.
(c) Hence, complete the circuit diagram for the mod-5 counter given in the figure using minimum number of 2-input NAND-gate only.

If the input X$$_3$$, X$$_2$$, X$$_1$$, X$$_0$$ to the ROM in figure 2.12 are 8-4-2-1 BCD numbers, then the outpus are Y$$_3$$,Y$$_2$$, Y$$_1$$, Y$$_0$$ are

4-bit 2’s complement representation of a decimal number is 1000. The number is

If the input to the digital circuit (in the figure) consisting of a cascade of 20 XOR-gates is X then the output Y is equal to

The gates G₁ and G₂ in figure have propagation delays of 10nsec and 20nsec respectively. If the input V_i makes an abrupt change from logic 0 to 1 at time t = t₀, then the output waveform V₀ is

The inputs to a digital circuit shown in Figure 9(a) are the external signals A, B and C. ( $$\overline A \,\overline B \,and\,\overline {C\,} $$ and are not available). The +5V power supply (logic 1) and the ground (logic 0) are also available. The output of the circuit is X = $$\overline A \,B + \,\overline A \,\overline B \,\,\overline {C\,} $$
(a) Write down the output function in its canonical SOP and POS forms.
(b) Implement the circuit using only two 2:1 multiplexers shown in the Figure where S is the data-select line, $${D_0}\,$$ and $${D_1}\,$$ are the input data lines and Y is the output lines. The function table for the multiplexer is given in table

The VSWR can have any value between

In an impedance Smith chart, a clockwise movement along a constant resistance circle gives rise to

A plane wave is characterized by $$$\overrightarrow E = \left( {0.5\mathop x\limits^ \cap + \mathop y\limits^ \cap \,{e^{j\pi /2}}} \right){e^{j\omega t - jkz}}.$$$

This wave is

Distilled water at $${25^ \circ }C$$ is characterized by $$\sigma = 1.7 \times {10^{ - 4}}$$ mho/m and $$ \in = 78{ \in _0}$$ at a frequency of $$3 GHz$$. Its loss tangent $$\tan \delta $$ is

The phase velocity for the $$T{E_{10}}$$ mode in an air-filled rectangular waveguide is

A person with a receiver is 5 Km away from the transmitter. What is the distance that this person must move further to detect a 3-dB decrease in signal strength?

Consider a linear array of two half - wave dipoles A and B as shown in Fig. The dipoles are $${\lambda \over 4}$$ apart and are excited in such a way that the current on element B lags that on element A by $${90^0}$$ in phase

(a) Obtain the expression for the radiation pattern for E in the XY plane, i.e.,$$\left( {\theta = {{90}^0}} \right)$$.
(b) Sketch the radiation pattern obtained in (a).

The line-of-sight communication requires the transmit and receive antennas to face each other. If the transmit antenna is vertically polarized for best reception the receiver antenna should be

Consider a parallel plate waveguide with plate separation d as shown in Fig. The electric and magnetic fields for the TEM mode are given by $${E_x} = \,{E_0}\,\,{e^{ - j\,k\,z + j\,\omega \,t}},\,{H_y} = {{{E_0}} \over \eta }\,{e^{ - j\,k\,z + j\,\omega \,t}}$$

Where $$k = \,\,\eta \,\omega \,\, \in $$
(a) Determine the surface charge densities $${\rho _s}$$ on the plates at x = 0 and x = d
(b) Determine the surface current densities $$\mathop {{J_s}}\limits^ \to $$ on the same plates.
(c) Prove that $${\rho _s}$$ and $$\mathop {{J_s}}\limits^ \to $$ satisfy the current continuity condition.

Consider a parallel plate waveguide with plate separation d as shown in Fig. The electric and magnetic fields for the TEM mode are given by $${E_x} = \,{E_0}\,\,{e^{ - j\,k\,z + j\,\omega \,t}},\,{H_y} = {{{E_0}} \over \eta }\,{e^{ - j\,k\,z + j\,\omega \,t}}$$

Where $$k = \,\,\eta \,\omega \,\, \in $$
(a) Determine the surface charge densities $${\rho _s}$$ on the plates at x = 0 and x = d
(b) Determine the surface current densities $$\mathop {{J_s}}\limits^ \to $$ on the same plates.
(c) Prove that $${\rho _s}$$ and $$\mathop {{J_s}}\limits^ \to $$ satisfy the current continuity condition.

Consider a parallel plate waveguide with plate separation d as shown in Fig. The electric and magnetic fields for the TEM mode are given by $${E_x} = \,{E_0}\,\,{e^{ - j\,k\,z + j\,\omega \,t}},\,{H_y} = {{{E_0}} \over \eta }\,{e^{ - j\,k\,z + j\,\omega \,t}}$$

Where $$k = \,\,\eta \,\omega \,\, \in $$
(a) Determine the surface charge densities $${\rho _s}$$ on the plates at x = 0 and x = d
(b) Determine the surface current densities $$\mathop {{J_s}}\limits^ \to $$ on the same plates.
(c) Prove that $${\rho _s}$$ and $$\mathop {{J_s}}\limits^ \to $$ satisfy the current continuity condition.

The intrinsic carrier concentration of silicon sample at 300^oK is $$1.5\times10^{16}/m^3$$. If after doping, the number of majority carriers is $$5\times10^{20}/m^3$$ , minority carrier density is

The band gap of silicon at 300 K is

In the figure, a silicon diode is carrying a constant current of 1 mA. When the temperature of the diode is 20°C, V_D is found to be 700 mV. If the temperature rises to 40°C, V_D becomes approximately equal to

If the transistor in Figure is in saturation, then

Consider the following assembly language program. The execution of the above program in an 8085 microprocessor will result in

The contents of Register (B) and Accumulator (A) of 8085 microprocessor are 49H and 3AH respectively. The contents of A and the status of carry flag (CY) and sign flag (S) after executing SUB B instructions are

The switch in Fig. has been in position $$1$$ for a long time and is then moved to position $$2$$ at $$t\, = \,0$$.

(a) Determine $${V_C}\left( {{0^ + }} \right)$$ and $${I_{_L}}\left( {{0^ + }} \right)$$
(b) Determine $${{d{V_C}\left( t \right)} \over {dt}}\,\,$$ at $$t\, = \,{0^ + }$$
(c) Determine $${{V_C}\left( t \right)}$$ for $$t > 0$$

For network shown in Fig. $$R\, = \,1\,k\Omega $$
$${L_1} = 2\,H,\,{L_2} = 5\,H,\,{L_3}\, = \,1H,{L_4} = 4H\,\,\,$$ and $$C - 0.2\,\,\mu F.$$. The mutual inductances are $${M_{12}} = 3\,H$$ and $${M_{34}} = 2\,H$$.

Determine
(a) the equivalent inductance for the combination of $${L_3}$$ and $${L_4}$$,
(b) the equivalent inductance across the points A and B in the network,
(c) the resonant frequency of the network.

Consider the network in Fig.

(a) Find its short-circuit admittance parameters.
(b) Find the open-ciruit impedance $${Z_{22}}$$.

The dependent current source shown in Figure

In the network of Figure, the maximum power is delivered to R_L if its value is

In figure, the switch was closed for a long time before opening at t = 0. the voltage V_x at t = 0⁺ is

If the 3-phase balanced source in Fig. delivers 1500 W at a leading power factor of 0.844, then the value of Z_L (in ohm) is approximately

The differential equation for the current i(t) in the circuit of Fig. is

The Fourier transform F $$\left\{ {{e^{ - t}}u(t)} \right\}$$ is equal to $${1 \over {1 + j2\pi f}}$$. Therefore, $$F\left\{ {{1 \over {1 + j2\pi t}}} \right\}$$ is

The Laplace transform of a continuous - time signal x(t) is $$X\left( s \right) = {{5 - s} \over {{s^2} - s - 2}}$$. If the Fourier transform of tyhis signal exists, then x(t) is

Convolution of x(t + 5) with impulse function $$\delta \left( {t\, - \,7} \right)$$ is equal to

A deterministic signal x(t) = $$\cos (2\pi t)$$ is passed through a differentiator as shown in Figure.
(a) Determine the autocorrelation R_xx ($$\tau $$) and the power spectral density S_xx(f).
(b) Find the output power spectral density S_yy( f ).
(c) Evaluate R_xy(0) and R_xy(1/4).

If the impulse response of a discrete-time system is $$h\left[ n \right]\, = \, - {5^n}\,\,u\left[ { - n\, - 1} \right],$$ then the system function $$H\left( z \right)\,\,\,$$ is equal to

Consider a sampled signal $$y\left( t \right) = 5 \times {10^{ - 6}}\,x\left( t \right)\,\,\sum\limits_{n = - \infty }^{ + \infty } {\delta \left( {t - n{T_s}} \right)} $$

where $$x\left( t \right) = 10\,\,\cos \,\left( {8\pi \times {{10}^3}} \right)\,\,t$$ and
$${T_s} = 100\,\,\mu \sec .$$ When $$y\left( t \right)$$ is passed through an ideal low-pass filter with a cutoff frequency of 5 KHz, the output of the filter is

A linear phase channel with phase delay $${\tau _p}$$ and group delay $${\tau _g}$$ must have

In Fig. m(t) = $$ = {{2\sin 2\pi t} \over t}$$, $$s(t) = \cos \,200\pi t\,\,andn(t) = {{\sin 199\pi t} \over t}$$.

The output y(t) will be

A signal x(t) = 100 cos $$(24\pi \times {10^3})$$ t is ideally sampled with a sampling period of 50 $$\mu \sec $$ and then passed through an ideal low pass filter with cutoff frequency of 15 KHz. Which of the following frequencies is/ are present at the filter output?

Which of the following cannot be the Fourier series expansion of a periodic signal?