GATE ECE 2004 PYQ

Assuming = 0.2 V and = 50, the minimum base current ( ) required to drive the transistor in the figure to saturation is

The circuit in the figure is a

A bipolar transistor is operating in the active region with a collector current of 1 mA. Assuming that the of the transistor is 100 and the thermal voltage ( ) is 25 mV, the transconductance ( ) and t

Assume that the of transistor is extremely large and = 0.7V, and in the circuit shown in the figure are

In the op-amp circuit given in the figure, the load current is

The value of C required for sinusoidal oscillations of frequency 1 kHz in the circuit of the figure is

In a full-wave rectifier using two ideal diodes, and are the dc and peak values of the voltage respectively across a resistive load. If PIV is the peak inverse voltage of the diode, then the appropria

Voltage series feedback (also called series-shunt feedback) results in

An ideal op-amp is an ideal

In the voltage regulator shown in the figure, the load current can vary from 100 mA to 500 mA. Assuming that the Zener diode is ideal (i.e., the Zener knee current is negligibly small and Zener resist

Two sinusoidal signals of same amplitude and frequencies 10 kHz and 10.1 kHz are added together. The combined signal is given to an ideal frequency detector. The output of the detector is

In a PCM system, if the code word length is increased from 6 to 8 bits, the signal to quantization noise ratio improves by the factor

Consider a binary digital communication system with equally likely 0's and 1's. When binary 0 is transmitted the detector input can lie between the levels -0.25 V and +0.25 V with equl probability : w

An AM signal is detected using an envelop detector. The carrier frequency and modulating signal frequency are 1 MHz and 2 kHz respectively. An appropriate value for the time constant of the envelop de

Consider a system shown in the figure. Let X(f) and Y(f) and denote the Fourier transforms of x(t) and y(t) respectively. The ideal HPF has the cutoff frequency 10 kHz. The positive frequencies where

Choose the correct one from among the alternatives A,B,C,D after matching an item from Group 1 most appropriate item in Group 2.

A 100 MHz carrier of 1 V amplitude and a 1 MHz modulating signal of 1 V amplitude are fed to a balanced modulator. The ourput of the modulator is passed through an ideal high-pass filter with cut-off

An AM signal and a narrow-band FM signal with identical carriers, modulating signals and modulation indices of 0.1 are added together. The resultant signal can be closely approximated by

The distribution function of a random variable X is shown in the figure. The probability that X=1 is

In the output of a DM speech encoder, the consecutive pulses are of opposite polarity during time interval . This indicates that during this interval

Three analog signals, having bandwidths 1200 Hz, 600 Hz and 600 Hz, are sampled at their respective Nyquist rates, encoded with 12 bit words, and time division multiplexed. The bit rate for the multip

Consider the signal x(t) shown in Fig. Let h(t) denote the impulse response of the filter matched to x(t), with h(t) being non-zero only in the interval 0 to 4 sec. The slope of h(t) in the interval 3

A random variable X with uniform density in the interval 0 to 1 is quantized as follows : If 0 X 0.3, = 0 If 0.3 X 1, = 0.7 where is the quantized value of X. The root-mean square value of the quantiz

A 1 mW video signal having a bandwidth of 100 MHz is transmitted to a receiver through cable that has 40 dB loss. If the effective one-side noise spectral density at the receiver is Watt/Hz, then the

A source produces binary data at the rate of 10 kbps. The binary symbols are represented as shown in the figure given below. The source output is transmitted using two modulation schemes, namely Binar

A system has poles at 0.1 Hz, 1 Hz and 80 Hz; zeros at 5 Hz, 100 Hz and 200 Hz. The approximate phase of the system response at 20 Hz is

A causal system having the transfer function H(s)=1/(s+2) is excited with 10u(t). The time at which the output reaches 99% of its steady state value is

The gain margin for the system with open-loop transfer function , is

The state variable equations of a system are : 1. 2. The system is

Consider the signal flow graph shown in Fig. The gain is

Consider the Bode magnitude plot shown in the fig. The transfer function H(s) is

Given , the point of intersection of the asymptotes of the root loci with the real axis is

A system described by the following differential equation is initially at rest. For input x(t)=2u(t), the output y(t) is

For the polynomial , the number of roots which lie in the right half of the s -plane is

The open-loop transfer function of a unity feedback system is . The range of K for which the system is stable is

Given , the state transition matrix is given by

The figure the internal schematic of a TTL AND-OR-Invert (AOI) gate. For the inputs shown in the figure, the output Y is

11001, 1001, 111001 correspond to the 2's complement representation of which one of the following sets of number

A digital system is required to amplify a binary-encoded audio signal. The user should be able to control the gain of the amplifier from minimum to a maximum in 100 increments. The minimum number of b

The Boolean expression AC+ B is equivalent to

In the modulo-6 ripple counter shown in figure, the output of the 2- input gate is used to clear the J-K flip-flop. The 2-input gate is

A master - slave flip flop has the characteristic that

A Boolean function f of two variables x and y is defined as follows : f (0,0) = f (0,1) = f (1,1) = 1; f (1,0) = 0 Assuming complements of x and y are not available, a minimum cost solution for realiz

Choose the current one from among the alternative A,B,C,D after matching an item from Group 1 with the most appropriate item in Group 2.

The range of signed decimal numbers that can be represented by 6-bits 1's complement number is

The minimum number of 2 to 1 multiplexers required to realize a 4 to 1 multiplexers is

Given figure is the voltage transfer characteristic of

Consider a 300 , quarter-wave long (at 1 GHz) transmission line as shown in Fig. It is connected to a 10V, 50 source at one end and is left open circuited at the other end. The magnitude of the voltag

A plane electromagnetic wave propagating in free space is incident normally on a large slab of loss-less, non-magnetic, dielectric material with . Maxima and minima are observed when the electric fiel

Consider an impedance Z = R + jX marked with point P in an impedance Smith chart as shown in Fig. The movement from point P along a constant resistance circle in the clockwise direction by an angle 45

In a microwave test bench, why is the microwave signal amplitude modulated at 1 kHz

The phase velocity of an electromagnetic wave propagating in a hollow metallic rectangular waveguide in the mode is

A lossless transmission line is terminated in a load which reflects a part of the incident power. The measured VSWR is 2. The percentage of the power that is reflected back is

A parallel plate air-filled capacitor has plate area of and plate separation of m. It is connected to a 0.5V, 3.6 GHz source. The magnitude of the displacement current is ( )

If and , the time-averaged Poynting vector is

The impurity commonly used for realizing the base region of a silicon n - p - n transistor is

Consider the following statements S1 and S2. S1 : The threshold voltage ( ) of MOS capacitor decreases with increase in gate oxide thickness. S2 : The threshold voltage ( ) of a MOS capacitor decrease

The resistivity of a uniformly doped n-type silicon sample is 0.5 - mc. If the electron mobility ( ) is 1250 /V-sec and the charge of an electron is Coulomb, the donor impurity concentration ( ) in th

In an abrupt p-n junction, the doping concentrations on the p-side and n-side are and respectively. The p-n junction is reverse biased and the total depletion width is 3 m. The depletion width on the

The neutral base width of a bipolar transistor, biased in the active region, is 0.5 m. The maximum electron concentration and the diffusion constant in the base are and /sec respectively. Assuming neg

Consider the following statements S1 and S2. S1 : The of a bipolar transistor reduces if the base width is increased. S2 : The of a bipolar transistor increases if the dopoing concentration in the bas

If for a silicon npn transistor, the base-to-emitter voltage ( ) is 0.7 V and the collector-to-base voltage ( ) is 0.2 V, then the transistor is operating in the

Consider an abrupt p-n junction. Let be the built-in potential of this junction and be the applied reverse bias. If the junction capacitance ( ) is 1 pF for =1V, then for =4V, will be

The drain of an n-channel MOSFET is shorted to the gate so that . The threshold voltage ( ) of the MOSFET is 1 V. If the drain current ( ) is 1 mA for =2V, then for =3V, is

The longest wavelength that can be absorbed by silicon, which has the bandgap of 1.12 eV, is 1.1 m. If the longest wavelength that can be absorbed by another material is 0.87 m, then bandgap of this m

It is desired to multiply the numbers 0AH by 0BH and store the result in the accumulator. The numbers are available in registers B and C respectively. A part of the 8085 program for this purpose is gi

Consider the sequence of 8085 instructions given below LXI H, 9258 MOV A, M CMA MOV M, A Which one of the following is performed by this sequence ?

The 8255 Programmable Peripheral Interface is used as described below. (i) An A/D converter is interface to a microprocessor through an 8255. The conversion is initiated by a signal from the 8255 on P

The number of memory cycles required to execute the following 8085 instructions (i) LDA 3000 H (ii) LXI D, FOF1H would be

Consider the following statements S1 and S2 S1 : At the resonant frequency the impedance of a series RLC circuit is zero. S2 : In a parallel GLC circuit, increasing the conductance G results in increa

The circuit shown in the figure, with and C = 3 F has input voltage v(t) = sin2t. The resulting current i(t) is

For the R - L circuit shown in the figure, the input voltage (t) = u(t). The current i(t) is

The circuit shown in the figure has initial current through the inductor and an initial voltage across the capacitor. For input v(t)=u(t), the Laplace transform of the current i(t) for t 0 is

The transfer function of an RLC circuit is given by . The Quality factor (Q-factor) of this circuit is

The equivalent inductance measured between the terminals 1 and 2 for the circuit shown in the figure is

For the lattice shown in the figure, . The values of the open circuit impedance parameters are

Consider the network graph shown in the figure. Which one of the following is NOT a 'tree' of this graph ?

For the circuit shown in the figure, the initial conditions are zero. Its transfer function is

For the circuit shown in the figure, the time constant RC = 1 ms. The input voltage is . The output voltage is equal to

Consider the sequence x[n]=[-4-j51+j25]. The conjugate anti-symmetric part of the sequence is

The z-transform of a system is . If the ROC is , then the impulse response of the system is

A 1 kHz sinusoidal signal is ideally sampled at 1500 samples/sec and the sampled signal is passed through an ideal low-pass filter with cut-off frequency 800 Hz. The output signal has the frequency.

A rectangular pulse train s(t) as shown in the figure is convolved with the signal (4p 1 t). The convolved signal will be a

The impulse response h[n] of a linear time-invariant system is given by h[n]=u[n+3] + u[n-2) - 2n[n-7] where u[n] is the unit step sequence. The above system is

The Fourier transform of a conjugate symmetric function is always

The impulse response h[n] of a linear time invariant system is given as If the input to the above system is the sequence , then the output is

Let x(t) and y(t) with Fourier transforms X(f) and Y(f) respectively be related as shown in Fig. Then Y(f) is

A causal LTI system is described by the difference equation 2y[n]=ay[n-2]-2x[n]+bx[n-1] The system is stable only if