Technical Aptitude

1) What does the following equivalency imply?

a) an LTI system b) a linear system c) both a & b d) none of the above

2) For the below circuit, when the switch is closed at t=0, what can be the waveform of v(t)?

a) b) c) d)

3) For a signal x(t) which of the following statements is false, if x(t) converges?

a) x(t)à0 as tà∞ b) x(t)àa as tà∞ c) Both a & b d)none of these.

4)

i) ii) iii) iv)

Which of the above statements is/are true?

a)i & iv b)ii & iv c)i & iii d)ii & iii

5) In a receiver, a station with f_c = 1000 kHz is to be detected. Local oscillator is tuned to a frequency of 1455 kHz. It is found to detect another station. The difference in frequencies between the two stations is

a) 910 kHz b) 455 kHz c) 1000 kHz d) 227.5 kHz

6) For instability to occur in an op-amp, the closed loop gain of the op-amp must be

a) greater than 1 b) less than 1 c) equal to 1 d) none of the above

7) A certain BPF has a centre frequency of 4 kHz and a bandwidth of 2 kHz. Quality factor is

a) 0.5 b) 2 c) 4 d) 8

8) What is the backbone technology behind ISDN?

a) Cell Relay b) ATM c) Frame Relay d) X.25

9) In a CE amplifier, if collector-emitter voltage increases, the instantaneous operating point

a) Moves up to the load line b) Moves down the load line

c) Moves at right angle to the load line d) remains stationary

10) Load regulation is determined by

a) changes in load current and input voltage b) changes in load current and output voltage

c) changes in load resistance and input voltage d) changes in zener current and load current

11) A diode that has a negative resistance characteristics is the

a) tunnel diode b) Schottky diode c) LASER diode d) hot-carrier diode

12) Electron-Hole pairs are produced by

a) Recombination b) Thermal energy c) ionization d) doping

13) In cutoff, V_CE is

i) 0 v ii) minimum iii) maximum iv) equal to V_CC

a) ii & iv b) iii & iv c) i & iii d) iv alone

14) If the base-emitter junction is open, the collector voltage is

a) V_CC b) 0 V c) floating d) 0.2 V

15) The input resistance at the base of a biased transistor depends mainly on

a) β_dc b) R_B c) R_E d) β_dc & R_E

16) When the voltage gain of an amplifier is increased, the bandwidth

a) is not affected b) increases c) decreases d) becomes distorted

17) The constant current region of an FET lies between

a) cutoff and saturation b) cutoff and pinch off c) 0 and I_DSS

d) pinch off and breakdown

18) A voltage follower

a) has a gain of 1 b) is non-inverting

c) has no feedback resistor d) all of the above

19) When filters are cascaded, the roll off rate

a) increases b) decreases c) does not change

20) The term OTA means

a) Operational transistor amplifier b) Operational transformer amplifier

c) Operational transconductance amplifier d) Output transducer amplifier

21) The output of Mealy Machine depends on

a) Present state b) inputs c) Both a & b d) Next State

22) Which of the following families has a high noise margin?

a) TTL b) Schottky TTL c) ECL d) CMOS

23) n-channel MOS conducts when V_GS is

a) positive b) negative c) 0 v d) None of the above.

24) How many 3 to 8 Decoders are needed to construct 6 to 64 Decoder?

a) 10 b) 9 c) 8 d) 2

25) For the below circuit, taking open as 0 and closed as 1, expression for Y is

a) A+(B+C)D b) A+BC+D c) A(BC+D) d) None of these

26) The current logging takes place in

a) RTL b) HTL c) DCTL d) TTL

27) Which of the following is the fastest A/D converter?

a) comparator converter b) counter type c) successive approximation

d) dual slope

28) What is the addressing mode used in LXI B 0345_H

a) Direct b) Indirect c) Immediate d) None of these

29) Which of these has the highest priority?

a) TRAP b) RST 6.5 c) RST 7.5 d) HOLD

30) The expression for Y is

a) AB b) A+B C) AB d) A+B

31) Which of the following is a 16 bit microprocessor?

a) 8085 b) 8086 c) Zilog 80 d) Motorola 6800

32) In order to enable INTR interrupt, which of the following are needed?

a) EI b) SIM c) both a & b d) None of these

33) In order to obtain correct output the input to a flip flop must be stable for

a) setup time b) hold time c) (a) + (b) d) (a) – (b)

34) Race condition arises in a

a) combinational circuit b) Asynchronous sequential circuit

c) Synchronous sequential circuit d) both b & c

35) Which is the frequency range used for Mobile Telephony?

a) 3-30 MHz b) 0.3-3 GHz c) 3-30 kHz d) None of these

36) find the RMS voltage output for the following circuit

a) 10/√2 V b) 9.3/√2 V c) 9.7/√2 V d) 0 V

37) which of the following statements are false?

i) DRAM is faster than SRAM ii) DRAM has higher packing density

iii) SRAM needs refreshing circuits iv) SRAM stores bit as a voltage

a) i & ii b) i & iii c) ii & iv d) i, ii & iii

38) Human eye is insensitive to which distortion?

a) amplitude b) Frequency c) Phase d) None of these

39) A sine wave with an amplitude of 3 Volts is quantized by an 8 bit ADC. The ADC full scale input range is from -6 to 6 volts. What is the SNR of sampled signal?

a) 44dB b) 88dB c) 22dB d) 11dB

40) In a typical signal processing application it is required to enhance the high frequency components linearly increasing with frequency. Then

a)Introduce a high pass filter with high, constant gain.

b) Pass the signal to a differentiator.

c)Pass the signal to a logarithmic amplifier.

d) It is not possible to perform such an operation

41) Which of the following statements are true?

i) DSB SC AM conserves more power than DSB AM.

ii) DSB AM conserves more power than DSB SC AM.

iii) DSB SC AM requires complicated circuitry when compared with others.

iv) DSB AM required complicated circuitry.

a) i & iii b) ii & iii c) i & iv d) ii & iv

42) What is the Video bandwidth used in HDTV?

a) 4.2 MHz b) 4.2 kHz c) 5 MHz d) 24.9 MHz

43) Which of the following is a non-causal system?

a) y[n] = x(n)cos(ωn+1) b) y[n] = x[-n] c) y[n] = x[n] + x²[n]

d) y[n] = x[n] + x[n-1]

44) If x(t) = 2cos(5пt) is sampled at a frequency of 7 kHz, then which of the following LPF will reconstruct the signal?

a)G = 2 * 10^-4_­, ω_c = 5 kHz.

b) G = 2, ω_c = 3.5 kHz

c)G = 4, ω_c = 3.5 kHz

d) G = 4 * 10^-4, ω_c = 3.5 kHz

45) An absolutely integrable signal x(t) has a pole at s=2. Then which can be true

i) x (t) is of finite duration.

ii) Could x(t) be left sided?

iii) Could x(t) be right sided?

iv) Could x(t) be two sided?

a) i & iii b) i & ii c) ii & iv d) ii & iii

46) The widely used modulation scheme for transmission of video signals in TV is

a) DSB-SC b) SSB c) VSB d) DSB

47) High fidelity music having a bandwidth of 20 kHz is to be recorded in a CD, using PCM. A guard band of 4.1 kHz is provided to minimize aliasing. If the ADC provides 16 bit quantization, then the bit rate recorded is

a) 1.544 Mbps b) 705.6 kbps c) 64 kbps d) 1.4112 Mbps.

48) Which of the following processors has an Harvard architecture?

a) 8086 microprocessor b) 8051 microcontroller c) TMS320C5402 DSP

d) none of the above.

49) Commercial FM broadcast stations us a maximum frequency deviation of

a) 75 kHz b) 75 MHz c) 45 kHz d) 45 MHz

50) A LPF is usually introduced prior to sampling because

a) A high frequency signal cannot be sampled.

b) The LPF time limits the signal.

c) The LPF prevents distortion of the sampled signal to be transmitted.

d) It avoids aliasing.