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DU PhD in informatics IIC
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Topic:- DU_J19_PHD_INFO
- If the differential voltage gain and the common mode voltage gain of a differential amplifier are 48dB and 2dB respectively, then its common rejection ratio is [Question ID = 25541]
- 23dB [Option ID = 42159]
- 46dB [Option ID = 42162]
- 50dB [Option ID = 42161]
- 25dB [Option ID = 42160]
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Correct Answer :-
23dB [Option ID = 42159]
- A video transmission system transmits 625 picture frames per second. Each frame consists of a 400×400 pixel grid with 64 intensity levels per pixel. The data rate of the system is [Question ID = 25555]
- 600Mbps [Option ID = 42218]
- 6.4Gbps [Option ID = 42216]
- 100Mbps [Option ID = 42217]
- 16Mbps [Option ID = 42215]
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Correct Answer :-
16Mbps [Option ID = 42215]
- The minimum number of comparators required to build an 8-bit flash ADC is [Question ID = 25550]
- 256 [Option ID = 42198]
- 255 [Option ID = 42197]
- 8 [Option ID = 42195]
- 63 [Option ID = 42196]
Correct Answer :-
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8 [Option ID = 42195]
- The minimum number of MOS transistors required to make a dynamic RAM cell is [Question ID = 25549]
- 2 [Option ID = 42192]
- 1 [Option ID = 42191]
- 3 [Option ID = 42193]
- 4 [Option ID = 42194]
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Correct Answer :-
1 [Option ID = 42191]
- Two 2's complement numbers having signs bits x and y are added and the sign bit of the result is z. Then, the occurrence of overflow is indicated by the Boolean function [Question ID = 25545]
- Xyz [Option ID = 42175]
- xy + yz + zX [Option ID = 42178]
- Xyz [Option ID = 42176]
- xyz + x y z [Option ID = 42177]
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Correct Answer :-
- A 0 and 6 counter consists of 3 flip flops and a combination circuit of 2 input gate(s). The combination circuit consists of [Question ID = 25547]
- one OR gate [Option ID = 42184]
- two AND gate [Option ID = 42186]
- one AND gate and one OR gate [Option ID = 42185]
- one AND gate [Option ID = 42183]
Correct Answer :-
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one AND gate [Option ID = 42183]
- X=01110 and Y=11001 are two 5-bit binary numbers represented in two's complement format. The sum of X and Y represented in two's complement format using 6 bits is [Question ID = 25543]
- 001000 [Option ID = 42168]
- 100111 [Option ID = 42167]
- 101001 [Option ID = 42170]
- 000111 [Option ID = 42169]
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Correct Answer :-
100111 [Option ID = 42167]
- In an M/M/1 queue for arrival rate A and service rate u, the average number of customer in the system is given by [Question ID = 25572]
- ? / (µ+ ?) [Option ID = 42286]
- (?- 1)/µ [Option ID = 4284]
- ? / (µ-?) [Option ID = 42285]
- ?/µ [Option ID = 42283]
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Correct Answer :-
?/µ [Option ID = 42283]
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- The depth of penetration of electromagnetic wave in a medium having conductivity o at a frequency of 1MHz is 25cm. The depth of penetration at a frequency of 4MHz will be [Question ID = 25528]
- 12.50cm [Option ID = 42109]
- 6.25cm [Option ID = 42107]
- 50.0cm [Option ID = 42108]
- 100.0cm [Option ID = 42110]
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Correct Answer :-
6.25cm [Option ID = 42107]
- Three identical amplifiers with each one having a voltage gain of 50, input resistance of 1k and output resistance of 2502, are cascaded. The open circuit voltage gain of the combined amplifier is [Question ID = 25542]
- 98dB [Option ID = 42164]
- 102dB [Option ID = 42166]
- 51dB [Option ID = 42165]
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Correct Answer :-
49dB [Option ID = 42163]
- A master-slave flip-flop has the characteristic that [Question ID = 25548]
- change in the output occurs when the state of the slave is affected. [Option ID = 42189]
- change in the output occurs when the state of the master is affected. [Option ID = 42188]
- change in the input immediately reflected in the output [Option ID = 42187]
- both the master and the slave states are affected at the same time. [Option ID = 42190]
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Correct Answer :-
change in the input immediately reflected in the output [Option ID = 42187]
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- For an energy state E of a photon gas, the density of states is proportional to [Question ID = 25536]
- E³/2 [Option ID = 42141]
- E² [Option ID = 42140]
- vE [Option ID = 42139]
- E [Option ID = 42142]
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Correct Answer :-
vE [Option ID = 42139]
- The equation of motion of a bead sliding on a uniform rod rotating in a force free space is [Question ID = 25525]
- ?-? = 0 [Option ID = 42095]
- r-rw² = 0 [Option ID = 42098]
- ? - ? = 0 [Option ID = 42096]
- ? - ? + ?² = 0 [Option ID = 42097]
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Correct Answer :-
?-? = 0 [Option ID = 42095]
- The line code that has zero dc component for pulse transmission of random binary data is [Question ID = 25554]
- alternate mark inversion (AMI) [Option ID = 42213]
- non-return to zero (NRZ) [Option ID = 42211]
- return to zero(RZ) [Option ID = 42212]
- none of these [Option ID = 42214]
Correct Answer :-
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non-return to zero (NRZ) [Option ID = 42211]
- An integral 7 over the counter-by I = ? dz/(z² + 1) If C is defined as |z| = 3, then the value of I is [Question ID = 25565]
- -3pisin(1) [Option ID = 42257]
- -2pisin(1) [Option ID = 42256]
- -4p? sin(1) [Option ID = 42258]
- -p? sin(1) [Option ID = 42255]
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Correct Answer :-
-p? sin(1) [Option ID = 42255]
- If the vector function F = (3y-az)i+ (bx-2z)j-(cy + z)k Is ir-rotational then the values of the constants a, b and c are [Question ID = 25561]
- 0.3, -2.5, 0.5 [Option ID = 42239]
- 4.0, 3.0, 2.0 [Option ID = 42242]
- 0.0, 3.0, 2.0 [Option ID = 42240]
- 0.3, 0.33, 0.5 [Option ID = 42241]
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Correct Answer :-
0.3, -2.5, 0.5 [Option ID = 42239]
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- The Fourier transform of a signal h(t)is H(jw) = (2 cosw) (sin 2w)/?. The value of h(0) is [Question ID = 25568]
- 1/2 [Option ID = 42267]
- 2 [Option ID = 42269]
- 1/4 [Option ID = 42268]
- 1 [Option ID = 42270]
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Correct Answer :-
1/2 [Option ID = 42267]
- The Fourier transform F{e-tu(t)} is equal to 1/(1+j2pf). Therefore, F{1/(1+j2nt)} is
- e-fu(-f) [Option ID = 42266]
- efu(-f) [Option ID = 42265]
- e-fu(f) [Option ID = 42264]
- efu(f) [Option ID = 42263]
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Correct Answer :-
efu(f) [Option ID = 42263]
- The eigenvalues and the corresponding eigenvectors of a 2 × 2 matrix are given by
Eigenvalue Eigenvector
?1 = 8 = [1]
?2 = 4 = [2]
[Question ID = 25559]- 16/24 + 6/4 [Option ID = 42232]
- 16/24 + 6/4 [Option ID = 42231]
- 16/24 + 6/4 [Option ID = 42233]
- 16/24 + 6/4 [Option ID = 42234]
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Correct Answer :-
- [1] [2] [Option ID = 42231]
- The wave function in the ground state of H-atom is given by ?(x) = (1/vpa³)e-r/a, the average value of r is [Question ID = 25531]
- 3a/2 [Option ID = 42120]
- 8 [Option ID = 42122]
- 2a/3 [Option ID = 42121]
- zero [Option ID = 42119]
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Correct Answer :-
zero [Option ID = 42119]
- Given that 3Li7 = 7.01816amu, 3Li6=6.01692amu, and on2 = 1.00893amu. The binding energy of neutron in a 3Li nucleus is [Question ID = 25537]
- 0.51MeV [Option ID = 42143]
- 1.04MeV [Option ID = 42144]
- 7.17MeV [Option ID = 42146]
- 2.08NeV [Option ID = 42145]
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Correct Answer :-
0.51MeV [Option ID = 42143]
- The intrinsic carrier concentration of silicon sample at 300K is 1.5 × 1016m-3. If after doping, the number of majority carriers is 5 × 1020m-3, the minority carrier density is [Question ID = 25540]
- 5.0 x 1020m-3 [Option ID = 42157]
- 4.50 x 1011m-3 [Option ID = 42155]
- 3.0 × 10-5m-3 [Option ID = 42158]
- 3.33 x 104m-3 [Option ID = 42156]
Correct Answer :-
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4.50 x 1011m-3 [Option ID = 42155]
- Consider the Fermi-Dirac distribution function f (E) at room temperature (300K), where E refers to energy. If Er is the Fermi energy, which of the following is true? [Question ID = 25535]
- f(E) is a step function [Option ID = 42135]
- f(E) is large and tends to infinity as E decreases much below EF. [Option ID = 42138]
- States with E < EF are filled completely [Option ID = 42137]
- f(EF) has a value of 0.5 [Option ID = 42136]
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Correct Answer :-
f(E) is a step function [Option ID = 42135]
- The transition probability matrix of a Markov chain, Xn , n = 1,2,3,... has states 1,2,3 is [0.1 0.5 0.4] P= [0.6 0.2 0.2] [0.3 0.4 0.3] and the initial distribution is p(0) = (0.7,0.2,0.1). Find P(X2 = 3). [Question ID = 25571]
- 0.379 [Option ID = 42280]
- 0.479 [Option ID = 42281]
- 0.579 [Option ID = 42282]
- 0.279 [Option ID = 42279]
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Correct Answer :-
0.279 [Option ID = 42279]
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- A rectangular waveguide of internal dimensions (a = 4cm and b = 3cm) is to be operated in TE11 mode. The minimum operating frequency is [Question ID = 25529]
- 5.0 MHz [Option ID = 42114]
- 5.0 GHz [Option ID = 42113]
- 6.25 GHz [Option ID = 42111]
- 6.25 MHz [Option ID = 42112]
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Correct Answer :-
6.25 GHz [Option ID = 42111]
- The state of an oscillator of angular frequency wis ?(x) = e-m?x²/h. Find <x>? [Question ID = 25530]
- zero [Option ID = 42117]
- 1/x [Option ID = 42116]
- 8 [Option ID = 42118]
- X [Option ID = 42115]
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Correct Answer :-
X [Option ID = 42115]
- The PDF of a Gaussian random variable X is given by Px (x) = 1/(v(18p))e-(x-4)²/18 The probability of the even {X = 4} is [Question ID = 25570]
- 1 [Option ID = 42278]
- 1/4 [Option ID = 42277]
- 0 [Option ID = 42276]
- 1/2 [Option ID = 42275]
Correct Answer :-
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1/2 [Option ID = 42275]
- The Boolean expression (X+Y)(X + Y) + (XY) + X simplifies to [Question ID = 25546]
- X [Option ID = 42179]
- X+Y [Option ID = 42182]
- XY [Option ID = 42181]
- Y [Option ID = 42180]
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Correct Answer :-
X [Option ID = 42179]
- The time averaged Poynting vector, in W/m², for a wave with E = 24ej(wt+ ßz) V/m in free space is [Question ID = 25527]
- 4.8k/p [Option ID = 42105]
- 2.4k/p [Option ID = 42103]
- -4.8k/p [Option ID = 42106]
- -2.4k/p [Option ID = 42104]
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Correct Answer :-
2.4k/p [Option ID = 42103]
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- Work done when a force F = (i+2j+3k) N acting on a particle takes it from the point r1 = (i+j+k)m to the point r2 = (i-j+2k)m is [Question ID = 25524]
- 3J [Option ID = 42093]
- -3J [Option ID = 42094]
- -1/3J [Option ID = 42091]
- -3/2J [Option ID = 42092]
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Correct Answer :-
-3J [Option ID = 42091]
- Leto(t) denote the delta function. The value of the integral ? d(t) cos(3t/2) dt is [Question ID = 25551]
- 1 [Option ID = 42199]
- p/2 [Option ID = 42202]
- -1 [Option ID = 42200]
- 0 [Option ID = 42201]
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Correct Answer :-
1 [Option ID = 42199]
- A DSB-SC signal is to be generated with a carrier frequency foc = 1MHz using a nonlinear device with input-output characteristic Vo = a0vi + a1vi³, where a0 and a1 are constants. The output of the non- linear device can be filtered by an appropriate band-pass filter. Let Vi = A*cos(2pfit) + m(t) where m(t) is the message signal. Then the value of f¹ (inMHz) is [Question ID = 25553]
- 0.5 [Option ID = 42210]
- 0.333 [Option ID = 42208]
- 1 [Option ID = 42207]
- 3 [Option ID = 42209]
Correct Answer :-
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1 [Option ID = 42207]
- Given an orthogonal matrix A = [1 1 1 1] [1 1 -1 -1] [1 -1 -1 1] Then [AAT]-1 [1 -1 1 -1] [Question ID = 25558]
- [1 0 0 1] [0 1 1 1] [1 1 0 0] [0 0 1 1] [Option ID = 42228]
- [0 0 0 0] [0 1 0 0] [1 0 1 1] [Option ID = 42230]
- [1 0 0 0] [0 1 0 0] [0 0 1 0] [Option ID = 42229]
- [1 0 0 0] [0 1 0 0] [0 0 1 0] [Option ID = 42227]
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Correct Answer :-
- [1 0 0 0] [0 1 0 0] [0 0 1 0] [Option ID = 42227]
- The first order perturbed Hamiltonian, when an external uniform electric field E is applied to the Z-axis on an atom is [Question ID = 25534]
- H' = -eEZ [Option ID = 42132]
- H' = eE/Z [Option ID = 42133]
- H' = eEZ [Option ID = 42131]
- H' = eZ/E [Option ID = 42134]
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Correct Answer :-
H' = eEZ [Option ID = 42131]
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- If the characteristic equation of the differential equation d2y/dx2+2ax+y=0 has two equal roots, then the values of a are [Question ID = 25562]
- 0,0 [Option ID = 42244]
- ±j [Option ID = 42245]
- ±1/2 [Option ID = 42246]
- ±1 [Option ID = 42243]
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Correct Answer :-
±1 [Option ID = 42243]
- The families of curves represented by the equation dy/dx = (x+y)/(x-y) For n = -1 and n = +1, respectively are [Question ID = 25563]
- Circles and Hyperbolas [Option ID = 42250]
- Hyperbolas and Circles [Option ID = 42248]
- Hyperbolas and Parabolas [Option ID = 42247]
- Parabolas and Circles [Option ID = 42249]
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Correct Answer :-
Hyperbolas and Parabolas [Option ID = 42247]
- The Hamiltonian corresponding to the Lagrangian L = ax2 + by2 - kxy is [Question ID = 25526]
- (Px2/4a) + (Py2/4b) ++ kxy [Option ID = 42101]
- (Px2/2ab) + (Py2/4b) ++ kxy [Option ID = 42102]
- (Px2/4a) - kxy [Option ID = 42100]
- (Px2/2a) + (Py2/2b) + kxy [Option ID = 42099]
Correct Answer :-
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(Px2/2a) + (Py2/2b) + kxy [Option ID = 42099]
- The nuclear spins of 6C14 and 12Mg25 nuclei are respectively [Question ID = 25538]
- zero and half integer [Option ID = 42147]
- half integer and zero [Option ID = 42148]
- Both half integer [Option ID = 42150]
- an integer and half integer [Option ID = 42149]
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Correct Answer :-
zero and half integer [Option ID = 42147]
- If x = v-1, then the value of xx is [Question ID = 25564]
- ep/2 [Option ID = 42252]
- e-p/2 [Option ID = 42251]
- px [Option ID = 42253]
- 1/x [Option ID = 42254]
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Correct Answer :-
e-p/2 [Option ID = 42251]
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- For real values of x, the minimum value of the function f(x) = exp(x) + exp (-x) is [Question ID = 25560]
- 2 [Option ID = 42237]
- 0 [Option ID = 42236]
- 1 [Option ID = 42235]
- 3 [Option ID = 42238]
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Correct Answer :-
1 [Option ID = 42235]
- Forl = 1, correct representation of Lx is [Question ID = 25532]
- h/v2 [0 1 0] [1 0 1] [0 1 0] [Option ID = 42123]
- h/v2 [1 0 1] [0 1 0] [1 0 1] [Option ID = 42126]
- h/v2 [1 0 1] [0 1 0] [1 0 1] [Option ID = 42125]
- h/v2 [0 1 0] [1 0 1] [0 1 0] [Option ID = 42124]
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Correct Answer :-
- h/v2 [0 1 0] [1 0 1] [0 1 0] [Option ID = 42123]
- An imperturbed two level system has energy levels E1 and E2 and eigen vectors [1] and [0]. When perturbed its Hamiltonian is represented by [E1 a] [a E2] The first order correction to E1is [Question ID =25533]
- zero [Option ID = 42127]
- 4a [Option ID = 42130]
- a [Option ID = 42129]
- 2a [Option ID = 42128]
Correct Answer :-
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zero [Option ID = 42127]
- Let A = [2 a] [1 -0.1] and A-1 = [b 0.5]. Then (a + b) equals [Question ID = 25557]
- 7/20 [Option ID = 42223]
- 3/20 [Option ID = 42224]
- 19/60 [Option ID = 42225]
- 11/20 [Option ID = 42226]
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Correct Answer :-
7/20 [Option ID = 42223]
- A solid uniform drum of mass m radius R rolls without slipping down a plane inclined at an angle 8. Find its acceleration? [Question ID = 25523]
- (3gsin ?)/2 [Option ID = 42088]
- -(2gsin ?)/3 [Option ID = 42089]
- -(3gsin ?)/2 [Option ID = 42090]
- (2gsin ?)/3 [Option ID = 42087]
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Correct Answer :-
(2gsin ?)/3 [Option ID = 42087]
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- Which of the following functions is analytic everywhere in the complex plane? [Question ID = 25567]
- cos(z) [Option ID = 42259]
- ln (z) [Option ID = 42261]
- 1/(1-z) [Option ID = 42262]
- e1/z [Option ID = 42260]
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Correct Answer :-
cos(z) [Option ID = 42259]
- The probability that an electron in a metal occupies the fermi level, at any temperature (T>0) [Question ID = 25539]
- 1 [Option ID = 42152]
- 2.0 [Option ID = 42154]
- 0 [Option ID = 42151]
- 0.5 [Option ID = 42153]
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Correct Answer :-
0 [Option ID = 42151]
- The Laplace transform of a unit ramp function starting at t=a, is [Question ID = 25569]
- e-as/(s+a)2 [Option ID = 42272]
- e-as/s4 [Option ID = 42274]
- e-as/s3 [Option ID = 42273]
- e-as/s2 [Option ID = 42271]
Correct Answer :-
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e-as/s2 [Option ID = 42271]
- An equivalent 2's complement representation of 2's complement number 1101 is [Question ID = 25544]
- 110111 [Option ID = 42173]
- 001101 [Option ID = 42172]
- 110100 [Option ID = 42171]
- 111101 [Option ID = 42174]
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Correct Answer :-
110100 [Option ID = 42171]
- An FM signal with modulation index 9 is applied to a frequency tripler. The modulation index in the output signal will be [Question ID = 25552]
- 0 [Option ID = 42203]
- 9 [Option ID = 42206]
- 27 [Option ID = 42204]
- -3 [Option ID = 42205]
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Correct Answer :-
0 [Option ID = 42203]
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- The bit rate of digital communication system is R kbits/s. The modulation used is 32-QAM. The minimum bandwidth required for ISI free transmission is [Question ID
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