
	Trending ▼ ICSE CBSE 10th ISC CBSE 12th CTET GATE UGC NET Vestibulares ResFinder

GATE 2002 : Electronics And Communication Engineering

20 pages, 102 questions, 2 questions with responses, 2 total responses,

	gate	+Fave Message
	Profile Timeline Uploads Q & A

Home > gate > F Also featured on: sree41

Instantly get Model Answers to questions on this ResPaper. Try now!
NEW ResPaper Exclusive!

Formatting page ...

For more files visit www.educationobserver.com/forum SECTION A (75 marks) 1. This question consists of TWENTY-FIVE sub-questions (1.1 1.25) of ONE mark each. For each of these sub-questions, four possible alternatives (A,B, C and D) are given, out of which ONLY ONE is correct. Indicate the correct answer by darkening the appropriate bubble against the question number on the left hand side of the Objective Response Sheet (ORS). You may use the answer book provided for any rough work, if needed. 1.1 The dependent current source shown in Figure 1.1 5 (a) delivers 80 W (b) absorbs 80 W + (c) delivers 40 W - V1=20V I V1 A 5 5 (d) absorbs 40 W 1.2 In figure 1.2, the switch was closed for a long time before opening at t = 0. the voltage Vx at t = 0+ is t=0 (a) 25 V (b) 50 V 2.5A (c) -50 V 20 (d) 0 V 5H - 20 + Vx 1.3 Convolution of x(t + 5) with impulse function (t 7) is equal to (a) x(t - 12) 1.4 (b) x(t + 12) (c) x(t - 2) (d) x(t + 2) Which of the following cannot be the Fourier series expansion of a periodic signal? (a) x(t) = 2cos t + 3 cos 3t (c) x(t) = cos t + 0.5 1.5 (b) x(t) = 2cos t + 7 cos t (d) x(t) = 2cos 1.5 t + sin 3.5 t In Figure 1.5, a silicon is carrying a constant current of 1 mA. When the temperature of the diode is 20 C, VD is found to be 700 mV. If the temperature rises to 40 C, VD becomes approximately equal to + (a) 740 mV (b) 660 mV 1mA VD (c) 680 mV (d) 700 mV - For more files visit www.educationobserver.com/forum 1.6 In a negative feedback amplifier using voltage-series (i.e. voltage-sampling series mixing) feedback. (Ri and Ro denote the input and output resistance respectively) (a) Ri decreases and Ro decreases (c) Ri increases and Ro decreases 1.7 (b) Ri decreases and Ro increases (d) Ri increases and Ro increases A 741-type op-amp has a gain-bandwidth product of 1 MHz. A non-inverting amplifier using this op-amp and having a voltage gain of 20 dB will exhibit a 3-dB bandwidth of (a) 50 KHz 1.8 (b) 100 KHz (c) 1000 KHz 17 (d) 1000 7.07 Three identical RC-coupled transistor amplifiers are cascaded. If each of the amplifiers has a frequency response as shown in Figure 1.8, the overall frequency response is as given in Av dB 0 -3 f 20Hz 1KHz Av dB Av dB (a) (b) 0 -3 0 -3 2 f f 40Hz (c) 40Hz 0.5KHz Av dB 1KHz (d) Av dB 0 -3 0 -3 f 40Hz f 2KHz 10Hz 1.9 0.5KHz 4-bit 2 s complement representation of a decimal number is 1000. The number is (a) +8 (b) 0 (c) -7 (d) -8 For more files visit www.educationobserver.com/forum 1.10 If the input to the digital circuit (Figure 1.10) consisting of a cascade of 20 XORgates is X, then the output Y is equal to 1 Y X (a) 0 1.11 (b) 1 (d) X The number of comparators required in a 3-bit comparator type ADC is (a) 2 1.12 (c) X (b) 3 (c) 7 (d) 8 If the transistor in Figure 1.12 is in saturation, then C IC IB dc denotes the dc current gain E (a) IC is always equal to dcIB (c) IC is greater than or equal to dcIB 1.13 (b) IC is always equal to - dcIB (d) IC is less than or equal to dcIB Consider a system with the transfer function G ( s ) = s+6 2 ks + s + 6 . Its damping ratio will be 0.5 when the value of k is (a) 1.14 2 6 (b) 3 (c) 1 6 (d) 6 Which of the following points is NOT on the root locus of a system with the open k loop transfer function G ( s ) H ( s ) = s ( s + 1) ( s + 3 ) (a) s = j 3 (b) s= - 1.5 (c) s= -3 (d) s = - For more files visit www.educationobserver.com/forum 1.15 The phase G (s) H (s) = margin of (1 s ) (1 + s ) (2 + s ) (a) 0 1.16 a system with the open-loop transfer function is (b) 63.4 (c) 90 (d) The transfer function Y ( s ) U ( s ) of a system described by the state equations x(t) = -2x(t) + 2u(t) and y(t) = 0.5x(t) is 1.17 (b) 0.5 s ( 2) } The Fourier transform F e 1u ( t ) is equal to (a) ef u ( f ) 1.18 1 s ( 2) { (a) (b) e f u ( f ) (c) 0.5 s ( + 2) (d) 1 s ( + 2) 1 1 . Therefore, F is 1 j 2 t + 1 + j2 f (c) ef u ( f ) (d) e f u ( f ) A linear phase channel with phase delay TP and group delay Tg must have (a) TP= Tg=constant (b) TP f and Tg f (c) TP = constant and Tg f (d) TP f and Tg =constant 1.19. A 1 MHz sinusoidal carrier is amplitude modulated by a symmetrical square wave of period 100 sec. Which of the following frequencies will NOT be present in the modulated signal? (a) 990 KHz (b) 1010 KHz (c) 1020 KHz 1.20. Consider a sampled signal y ( t ) = 5 10 6 x ( t ) + n = (d) 1030 KHz ( t nTs ) where x(t) =10 cos(8 103)t and Ts =100 sec. When y(t) is passed through an ideal low-pass filter with a cutoff frequency of 5KHz, the output of the filter is ( ) cos ( 8 10 ) t ( ) (a) 5 10 6 cos 8 103 t (b) 5 10 5 cos 8 103 t (c) 5 10 1 (d) 10 cos 8 103 t 3 ( ) 1.21. For a bit-rate of 8 Kbps, the best possible values of the transmitted frequencies in a coherent binary FSK system are (a) 16 KHz and 20 KHz (b) 20 KHz and 32 KHz (c) 20 KHz and 40 KHz (d) 32 KHz and 40 KHz 1.22. The line-of-sight communication requires the transmit and receive antenna to face each other. If the transmit antenna is vertically polarized, for best reception the receive antenna should be (a) horizontally polarized (b) vertically polarized For more files visit www.educationobserver.com/forum (c) at 45 with respect to horizontal polarization (d) at 45 with respect to vertical polarization 1.23. The VSWR can have any value between (a) 0 and 1 (b) -1 and +1 (c) 0 and (d) 1 and 1.24. In an impedance Smith chart, a clockwise movement along a constant resistance circle gives rise to (a) a decrease in the value of reactance (b) an increase in the value of reactance (c) no change in the reactance value (d) no change in the impedance value 1.25 The phase velocity for the TE10-mode in an air-filled rectangular waveguide is (c is the velocity of plane waves in free space) (a) less than c (b) equal to c (c) greater than c (d) none of the above 2. This question consists of TWENTY-FIVE sub-questions (2.1 2.25) of TWO marks each. For each of these sub-questions, four possible alternatives (A,B, C and D) are given, out of which ONLY ONE is correct. Indicate the correct answer by darkening the appropriate bubble against the question number on the left hand side of the Objective Response Sheet (ORS). You may use the answer book provided for any rough work, if needed. 2.1 In the network of Figure 2.1, the maximum power is delivered to RL if its value is I1 40 0.5I1 20 RL 50V (a) 16 (b) 40 3 (c) 60 (d) 20 For more files visit www.educationobserver.com/forum 2.2. If the 3-phase balanced source in Figure 2.2 delivers 1500 W at a leading power factor of 0.844, then the value of ZL (in ohm) is approximately (a) 90 32.44 3 PHASE BALANCED SOURCE (c) 80 32.44 (d) 90 32.44 2.3. ZL ZL (b) 80 32.44 400V ZL The Laplace transform of a continuous-time signal x(t) is X ( s ) = 5 s 2 s s 2 . If the Fourier transform of this signal exists, then x(t) is (a) e2t u ( t ) 2e t u ( t ) (c) e2t u ( t ) 2e t u ( t ) 2.4. (b) e2t u ( t ) + 2e t u ( t ) (d) e2t u ( t ) 2e t u ( t ) n If the impulse response of a discrete-time system is h n = 5 u n 1 , then the system function H(z) is equal to (a) (b) z and the system is stable z 5 (c) 2.5. z and the system is stable z 5 z and the system is unstable z 5 (d) z and the system is unstable z 5 An amplifier using an opamp with a slew-rate SR = 1V/ sec has a gain of 40 dB. If this amplifier has to faithfully amplify sinusoidal signals from dc to 20 KHz without introducing any slew-rate induced distortion, then the input signal level must not exceed. (a) 795 mV (b) 395 mV (c) 79.5 mV (d) 39.5 mV For more files visit www.educationobserver.com/forum 2.6. The circuit in Figure 2.6 employs positive feedback and is intended to generate Vf ( f ) 1 = 0 , then to sustain sinusoidal oscillation. If at a frequency f0 B ( f ) = V0 ( f ) 6 oscillation at this frequency R2 R1 - + + V0(f) + Vf(f) - (a) R2 = 5R1 2.7. Network B(f) - (b) R2 = 6R1 (c) R2 = R1 6 (d) R2 = R1 5 A zener diode regulator in Figure 2.7 is to be designed to meet the specifications: IL = 10 mA, V0 = 10 V and Vin varies from 30 V to 50 V. The zener diode has Vz = 10V and I zk (knee current) = 1 mA. For satisfactory opertion R (a) R 1800 (b) 2000 R 2200 + Dz (c) 3700 R 4000 IL=10mA + I2 Vo Vin RL (d) R>4000 - 2.8. The voltage gain A = VDD=+10V Vo of the Vi JFET amplifier shown in Figure 2.8 is RD(3K ) ID=1mA C2 (a) +18 + vo (b) -18 C1 (c) +6 (d) -6 + vi RG(1M ) - RS(2.5K ) CS For more files visit www.educationobserver.com/forum 2.9. The gates G1 and G2 in Figure 2.9 have propagation delays of 10 nsec and 20 nsec respectively. If the input Vi makes an abrupt change from logic 0 to 1 at time t = t0 then the output waveform V0 is G1 G2 0 V0 1 Vi 0 Vi 1 Vi to (a) (b) 1 1 0 0 t0 t1 t0 (c) t1 t2 t3 t0 t3 t2 t1 t2 t3 (d) 1 1 0 0 t0 t1 t2 t3 2.10. The circuit in Figure 2.10 has two CMOS NOR gates. This circuit functions as a: R VSS V0 (output) VSS 0 Vi C (a) flip flop (b) Schmitt trigger (c) Monostable multivibrator (d) Astable multivibrator For more files visit www.educationobserver.com/forum 2.11. Consider the following statements in connection with the CMOS inverter in Figure 2.11 where both the MOSFETs are of enhancement type and both have a thresh old voltage of 2V. Statement 1: T1 conducts when Vi 2V. Statement 2: T1is always in saturation when V0 = 0V. +5V T2 VI V0 T1 Which of the following is correct? (a) Only Statement 1 is TRUE (b) Only Statement 2 is TRUE (c) Both the statements are TRUE (d) Both the statements are FALSE 2.12. If the input X3 , X2 , X1 , X 0 to the ROM in figure 2.12 are 8-4-2-1 BCD numbers, then the outputs Y3Y2 Y1Y0 are 1 X3 0 1 0 X 2 X 1 X0 ROM BCD-to-Decimal DECODER D0 D1 .. D8 D9 0 1 X X X Y3 X X X X X X X X X Y2 X X Y1 X Y0 X X X X (a) gray code numbers (b) 2-4-2-1 BCD numbers (c) excess 3 code numbers (d) none of the above For more files visit www.educationobserver.com/forum 2.13. Consider the following assembly language program. MVI MOV A,B JMP NEXT MVI B,00H XRA B OUT START: B,87H PORT1 HLT NEXT: XRA B JP START OUT PORT2 HLT The execution of the above program in an 8085 microprocessor will result in (a) an output of 87H at PORT1 (b) an output of 87H at PORT2 (c) infinite looping of the program execution with accumulator data remaining at 00H (d) infinite looping of the program execution with accumulator data alternating between 00H and 87H 2.14. The system shown in Figure 2.14 remains stable when R(s) 1 k S-1 1 Y(s) 3 1 (a) k < - 1 (b) - 1 < k < 1 2.15. The transfer function of a system is G ( s ) = (c) 1 < k < 3 (d) k > 3 100 . For a unit step input ( s + 1) ( s + 100 ) to the system the approximate settling time for 2% criterion is (a) 100 sec (b) 4 sec (c) 1 sec (d) 0.01 sec For more files visit www.educationobserver.com/forum 2.16. The characteristic polynomial of a system is q ( s ) = 2s5 + s 4 + 4s3 + 2s2 + 2s + 1. The system is (a) stable (b) marginally stable (c) unstable (d) oscillatory 2.17. The system with the open loop transfer function G ( s ) H ( s ) = 1 ( 2 s s + s +1 ) has a gain margin of (a) - 6 dB (b) 0 dB (c) 3.5 dB (d) 6 dB 2.18. An angle modulated signal is given by ( ) s ( t ) = cos 2 2 106 t + 30 sin150t + 40 cos150t . The maximum frequency and phase deviations of s(t) are (a) 10.5 KHz, 140 rad (b) 6 KHz, 80 rad (c) 10.5 KHz, 100 rad (d) 7.5 KHz, 100 rad 2.19. In figure 2.19 m ( t ) = 2 sin 2 t sin199 t , s ( t ) = cos 200 t and n ( t ) = . The output t t y(t) will be Lowpass filter m(t) y(t) Cutoff frequency = 1Hz Passband Gain =1 (a) sin 2 t t n(t) s(t) (b) (c) sin 2 t sin 0.5 t cos1.5 t + t t (d) s(t) sin 2 t sin t cos 3 t + t t sin 2 t sin t cos 0.75 t + t t 2.20. A signal x(t) = 100 cos(24 103)t is ideally sampled with a sampling period of 50 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? (a) 12 KHz only (b) 8 KHz only (c) 12 KHz and 9 KHz (d) 12 KHz and 8 KHz 2 2 of d ( n ) = x ( n ) x ( n 1) is one-tenth the variance x 2.21. If the variance x of a stationary zero mean discrete time signal Rxx ( k ) autocorrelation function at k = 1 is 2 x(n), then the normalized x (a) 0.95 (b) 0.90 (c) 0.10 (d) 0.05 For more files visit www.educationobserver.com/forum j ur + ye 2 2.22. A plane wave is characterized by E = 0.5x e j t jkz . This wave is (a) linearly polarized (b) circularly polarized (c) elliptically polarized (d) unpolarized 2.23. Distilled water at 25 C is characterized by = 1.7 10-4 mho/m and =78 0 at a frequency of 3 GHz. Its loss tangent tan is ( = 10-9 /(36 )F/m) (a) 1.3 10-5 (b) 1.3 10-3 (c) 1.7 10-4/78 (d) 1.7 10-4/(78 0) 2.24. The electric field on the surface of a perfect conductor is 2 V/m. The conductor is immersed in water with =80 0. The surface charge density on the conductor is ( = 10-9 /(36 )F/m) (a) 0 C/m2 (b) 2 C/m2 (c) 1.8 10-11 C/m2 (d) 1.14 10-9 C/m2 2.25. 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? (a) 942 m (b) 2070 m SECTION B (c) 4978 m (d) 5320 m (75 Marks) This section consists of TWENTY questions (EC3-EC22) of FIVE marks each. Attempt ANY FIFTEEN questions. Answers must be given in the answer book provided. Answer for each question must start on a fresh page and must appear at one place only. (Answers to all parts of a question must appear together). 3. The switch in Figure 3 has been in position 1 for a long time and is then moved to position 2 at t = 0. 25k 10u(-t)V t=0 + - 1 IL 20k 5H 6V 20 F + VC - 4H 1k 50k ( ) (a) Determine VC 0+ ( ) and IL 0+ (c) Determine V (t) for t > 0 (b) Determine dVc ( t ) dt at t = 0+ For more files visit www.educationobserver.com/forum 4. For the network shown in Figure 4, R = 1 K , L1 = 2H, L2= 5H, L3 = 1H, L4 = 4H and C = 0.2 F. The mutual inductances are M12 = 3H and M34 = 2H. Determine (a) the equivalent inductance for the combination of L3 and L4. (b) the equivalent inductance across the points A and B in the network. (c) the resonant frequency of the network. I1 L1 R L3 A I2 Vs(t) ~ M12 L2 L4 B C 5. M34 Consider the network in Figure 5. 10 5 1 2 Ix I2+I1 PORT-1 PORT-2 2Ix 10 2 1 I2 (a) Find its short-circuit admittance parameters. (b) Find the open-circuit impedance Z22. 6. A triangular voltage waveform Vi(t) figure 6(a) is applied at the input to the circuit of Figure 6(b). Assume the diodes to be ideal. (a) Determine the output V0(t). (b) Neatly sketch the output waveform superimposed on the input Vi(t) and label the key points. D1 0.5K + Vi(t) + D2 12V Vi(t) 1K + 7V 0 t V0(t) 1.5K 5V - + - For more files visit www.educationobserver.com/forum 7. Figure 7 shows a 2-stage amplifier. The transistors Q1 and Q2 are identical with current gain = 100; further dc = ac = . The Zener diode Dz has a break down voltage Vz= 10.7 volt. Assume that Dz is in breakdown region and its dynamic resistance rz is zero. The capacitors C1 and C2 are large and provide negligible impedance at signal frequencies. VCC=+10V R RC2 930 4K C2 Q2 + VZ - DZ 4K + Vo - VC1 IC1 VEE=-10V + VS - RL Q1 C1 RB 930k (a) Identify the configuration in each of the amplifier stages (i.e., whether CE, CC, CB etc.) VEE=-10V (b) Determine the quiescent quantities IC1 and VC1. (c) Derive an expression for the voltage gain AV V0 and determine its value. Vs (Assume VBE = 0.7V, r0= and Thermal voltage VT = 25 mV) 8. Consider the circuit of Figure 8. The op-amp used is ideal. VCC1=+15V +5V VCC2=+12V R 100K Vi Vop + - RB Q 150K VEE2=-12V RF 10K RL IO 10 VEE1=-15V For more files visit www.educationobserver.com/forum (a) In which mode is the BJT operating (i.e. active, saturation or cutoff)? Justify your answer. (b) Obtain an expression relating the output current I0 and the input voltage Vi. (c) Determine I0 and V0P if Vi = 2 Volt (V0P:output of opamp) (Assume = 99 and VBE = 0.7 V) 9. The inputs to a digital circuit shown in Figure 9(a) are the external signals A, B and C. +5V D0 A B DIGITAL CIRCUIT Table 9 S S 0 D1 C Y D0 1 Y X D1 ( A, B and C are not available). The +5V power supply (logic 1) and the ground (logic 0) are also available. The output of the circuit is X = AB + A B 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 Figure 9(b), where S is the data-select line, D0 and D1 are the input data lines and Y is the output lines. The function table for the multiplexer is given in table 9. 10. Each transistor in Figure 10 has dc current gain dc = 50, cut-in voltage V = 0.65V and VBE, sat = 0.75 V. The output voltage V0 for T2 in saturation can be as high as 0.2 V. Assume 0.7 V drop across a conducting p-n junction. Determine? RC2=1k RB1 Vo(output) IB2 Vi(input) T2 T1 Rb=15k 2V + For more files visit www.educationobserver.com/forum (a) the minimum value IB2 necessary to keep T2 saturation. (b) the maximum permissible value for the resistance RB1. (c) the worst-case high input (logic 1) and the worst-case low input (logic 0) for which T2 will be either in saturation or in cut off. 11. It is required to design a binary mod-5 synchronous counter using AB flip-flops such that the output Q2Q1Q0 changes as 000 001 010 .. and so on. The excitation table for the AB flip-flop is given in table 11. (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, Q0 and their complements. (c) Hence, complete the circuit diagram for the mod-5 counter given in Figure 11 using minimum number of 2-input NAND-gate only. A B Qn+1 0 0 1 0 1 Qn 1 0 Qn 1 1 0 A2 Q2 A1 Q1 A0 Q0 B2 Q2 B1 Q1 B0 Q0 Clock 12. An 8085 microprocessor operating at 5 MHz clock frequency execute the following routine. START MOVE A,B OUT 55H DCR B STA FFF8H JMP START (a) Determine the total number of machine cycles required to execute this routine till the JMP instruction is executed for the first time. (b) Determine the time interval between two consecutive MEMW signals. For more files visit www.educationobserver.com/forum (c) If the external logic controls the READY line so that three WAIT states are introduced in the I/O WRITE machine cycle, determine the time interval between two consecutive MEMW signals. 13. A unity feedback system has the plant transfer function Gp ( s ) = 1 ( s + 1) (2s + 1) (a) Determine the frequency at which the plant has a phase lag of 90 k is placed in the feeds forward path of the feedback system. Find the value of k such that the compensated system has an open-loop gain margin of 2.5. (b) An integral controller with transfer function Gc ( s ) = (c) Determine the steady state errors of the compensated system to unit-step and unit-ramp inputs. 14. The Nyquist plot of an all-pole second order open-loop system is shown in Figure 14. Obtain the transfer function of the system. Imag -0.5 0.5 1 1.5 2 2.5 Real = -0.5 =0 -1 -1.5 -2 =2 15. -2.5 The block diagram of a linear time invariant system is given in Figure 15. U(s) - X2(s) 1/s 2 + + - X1(s) 1/s Y(s) For more files visit www.educationobserver.com/forum (a) Write down the state variable equations for the system in matrix form T assuming the state vector to be x1 ( t ) x2 ( 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 x1 (0) =1, and x2 (0) = 1. 16. A deterministic signal x(t) = cos2 t is passed through a differentiator as shown in Figure 16. x(t) y(t) 1 d 2 dt (a) Determine the autocorrelation Rxx (T) and the power spectral density Sxx(f). (b) Find the output power spectral density Syy(f). 1 (c) Evaluate Rxy(0) and Rxy . 4 17. A DSBSC modulated signal s(t) = 10 cos (2 106t+ )m(t-) is corrupted by an additive white Gaussian noise of power spectral density 10-4 W/Hz. The message power spectral density Smm(f) is as shown in Figure 17 and is uniformly distributed over the range 0 to 2 . Smm(f) 10-3 W/Hz -3KHz f +3KHz (a) Express the signal autocorrelation function RSS(T) in terms of the message autocorrelation function Rmm(T). Clearly state the necessary assumptions. (b) Determine the signal power spectral density SSS(f). (c) Find the power of the modulated signal and the noise power in the transmissions bandwidth. 18. A continuous time signal with finite energy, band limited from 3 MHz to 5 MHz is ideally sampled, encoded by a fixed length PCM coder and then transmitted over a digital channel of capacity 7 Mbps. The probability density function (pdf) at the output of the sampler is uniform over the range 2V to +2V. (a) Determine the minimum sampling rate necessary for perfect reconstruction. (b) Determine the maximum SNR (in dB) that may be achieved. For more files visit www.educationobserver.com/forum 19. A discrete memory-less source generates either 0 or 1 at a rate of 160 Kbps; 0 is generated three times more frequently than 1. A coherent binary PSK modulator is employed to transmit these bits over a noisy channel. The received bits are detected in a correlator fed with the basis function of unit energy (for this binary PSK scheme) as the reference signal. The receiver makes a decision in favour of 1 if the correlator output is positive, else decides in favour of 0. If 0 and 1 are ( ) ( ) represented as 6 2 cos 640 103 t V and 6 2 cos 640 103 t V respectively, then (a) determine the transmitted signal energy per bit. (b) determine the basis function of unit energy for this binary PSK scheme. (c) determine the probability that the receiver makes a decision in favour of 1 when the channel noise is characterized as zero-mean AWGN with power N spectral density 0 = 3.125 10 4W / Hz 2 20. Transmission line transformation of a load ZL and Z is given by Z = Z0 ZL + jZ0 tan ( l ) Z0 + jZL tan ( l ) (a) Show that the above transformation implies that the impedance Z gets * transformed to ZL for real Z. (b) What is the importance of the result derived in (a)? 21. Consider a parallel plate wave-guide with plate separation d as shown in Figure 21 electric and magnetic fields for the TEM-mode are given by E x = E0e jkz + j t Hy = E0 jkz + j t e n where k = (a) Determine the surface charge densities p r s on the plates at x = 0 and x = d. (b) Determine the surface current densities J s on the same plates. r (c) Prove that ps and J s satisfy the current continuity condition. x d z For more files visit www.educationobserver.com/forum 22. Consider a linear array of two half-wave dipoles A and B as shown in Figure 22. The dipoles are apart and are excited in such a way that the current on 4 element B legs that on element A by 90 in phase. (a) Obtain the expression for the radiation pattern for E0in the XY plane (i.e, =90 ) (b) Sketch the radiation pattern obtained in (a). B A Y /4 =0 X

Formatting page ...

Top Contributors
to this ResPaper
(answers/comments)

Shivani Sura
(2)

Formatting page ...

Additional Info : Solved GATE exam paper study guide - gate 2002 : electronics and comm. engg. free online question paper
Tags : Gate Electronics and Comm Engg 2003 model paper, syllabus, EC paper, India, GATE Exam Question Papers, Free Online Solutions, Answers, Answer Key, Graduate Aptitude Test in Engineering, IIT, IISc, GATE Exam Syllabus, GATE Study Material, GATE Exam Pattern, gate exam papers, gate question papers 2016, 2015, 2014, 2013, 2012, 2011, 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003, 2002, 2001, 2000, 1999, 1998, 1997, 1996, 1995, 1994, 1993, 1992, 1991, past gate papers, gate papers with answers, gate entrance exam engineering, gate previous years papers, gate old papers, gpat.

gate chat

Horizontal lines at:
Guest Horizontal lines at:
AutoRM Data:
Box geometries: