ISRO Paper |   16872

ISRO Paper

                                            Latest ISRO Placement Paper

Latest ISRO placement Paper for preparation:

1.In an amplitude modulated system if the total power is 600W and the power in the carrier is 400W, the modulation index is

2.The channel capacity under the Gaussian noise environment, for a discrete memoryless channel with a bandwidth of 4MHz and SNR of 31 is.
a.20 Mbps
b.4 Mbps
c.8 kbps
d.4 kbps

3.In satellite communication, frequency modulation is used because satellite channel has
a. High modulation index 
b. Small bandwidth and negligible noise 
c. Large bandwidth and severe noise 
d. Maximum bandwidth and minimum noise 

4.For a 3-um-diameter optical fiber with core and cladding indexes of refraction of 1.545 and 1.510, respectively. The cut off wavelength is.

5.A 12-bit ADC is operating with a lus clock period and total conversion time is seen to be 14us always. The ADC must be of the type 
a. Flash type 
b. Counting type 
c. Integrating type 
d. Successive approximation type 

6.Consider the analog signal x(t) = 3cosl007ct. If the signal is sampled at 20011z, the discrete time signal obtained will be
d.3 cos(nnn/3 )

7.In VHDL all the statements written inside a process statement are
c.Both (a) and (b)
d.None of the above

8.A microprocessor with 12-bit address bus will be able to access --------------- kilobytes of memory

9.A practical current source is usually represented by
a.A resistance in series with an ideal current source.
b.A resistance in parallel with an ideal current source.
c.A resistance in parallel with an ideal voltage source.
d.None of the above.

10.The dominant mode in a rectangular wave guide is TEo, because this mode has
a. No attenuation 
b. No cutoff 
c. No magnetic field component 
d. The highest cut-off wavelength 

11.A PN junction in series with a 100 ohm resistor is forward biased so that a current of 100 mA flows. If voltage across the combination is instantaneously reversed to 10V at time t = 0, the reverse current that flows through the junction at t = 0 is approximately given by.
a.0 mA
b.200 mA
c.50 mA
d.100 mA

12.Ripple factor for a half wave rectifier is

13. -------- is a primitive that can execute code. It contains an instruction pointer (=program counter) and sometimes has its own stack 
a. Process 
b. Task 
c. Kernel 
d. Thread 

14.A wave guide section in a microwave circuit will act as a
a. Low pass filter 
b. Band pass filter 
c. High pass filter 
d. Band stop filter  

15.A signal ml (t) is band limited to 3.6 kHz and the three other signals m2(t),m3(t) and m4(t) are band limited to 1.2 kHz each, and these signals are transmitted by means of TDM. Then, what will be the transmission bandwidth of the channel.
a.7.2 KHz
b.14.4 KHz
c.3.6 KHz
d.2.4 KHz

16.For a 10 bit PCM system the signal to quantization noise ratio is 62dB. If the number of bits is increased by 2, then the signal to quantization noise ratio will 
a. Increase by 6 dB 
b. Increase by 12 dB 
c. Decrease by 6 dB 
d. Decrease by 12 dB 

17. The modulation normally used with the digital data is 
a. FM 
b. AM 
c. SSB 

18. Which of the following statements with reference to a generic microprocessor is correct? 
a. Instruction cycle time period is exactly equal to machine cycle time period 
b. Instruction cycle time period is shorter than machine cycle time period 
c. Machine cycle time period is shorter than instruction cycle time period 
d. Instruction cycle time period is exactly half of machine cycle time period 

19. An electric iron designed for 110V AC supply was rated at 500W. It was put across a 220V supply. Assuming that at 110V it supplied 500W output (i.e no losses) at the new voltage it will supply

20. In a Class AB amplifier, the current flows through the active device for
a.Less than half of the duration of input cycle
b.Half duration of input cycle
c.More than half but less than full cycle duration
d.Full duration of input cycle

21. Which of the following is not true regarding a preemptive kernel
a. If a high priority thread becomes ready to run, low priority thread is preempted -b. The kernel checks for the high priority ready to run threads when ever called----
c. The executing thread is never interrupted 
d. There are special demands on communication between threads and handling common resources 

22.The intermediate frequency of a super-heterodyne receiver is 450 KHz. If it is tuned to 1200 KHz, the image frequency will be
a.750 KHz
b.900 KHz
c.1600 KHz
d. 2100 KHz

23.Geo-stationary satellites are placed in equatorial orbits at the height approximately
a.1000 km
b.15000 km
c.25000 km
d.36000 km

24.For a single mode optical cable with 0.25dB/km loss, the optical power 100km from a 0.1mW source will be

25.The function of a strobe function in digital system is
a. To reset memory register. 
b. To check the functioning of a logic gate 
c. To avoid race problem 
d. To tri-state the output of the register 

26.When a microprocessor interfaces with a peripheral or memory device, the normal timing of the microprocessor may need to be altered by introducing
b.Wait states
c.Tristate logics
d.None of the above

27.In phase modulated signal, the frequency deviation is proportional to
a.Frequency only
b.Amplitude only
c.Both (a) and (b)
d.none of the above

28.For a fast communication which of the following requirements have to be met
a. Large bandwidth 
b. High S/N ratio 
c. High channel capacity 
d. None of the above 

29.The impulse response of a linear time invariant system ish (n) = {1, 2, 1,-1}. The response for the input signal x(n) = {1,2,3,1}is
a.{ 1,8,4,8,3),-1,-2}
b.{ 1, 4, 8, 3, 8, -2, -2}
c.{1, 4,8,8, 3,-2, -1}
d.{1,8,3,8, 8,4,-1}

30. In a 8085 microprocessor system with memory mapped I/O 
a. I/O devices have 8 bit address 
b. I/O devices are accessed using IN and OUT instructions. 
c. There can be maximum 256 input and 256 output devices 
d. Arithmetic and logic operations can be directly performed with I/O data 

31.For an earth station transmitter input power of 40dBW (10,000W),with a back off loss of 3dB, a total branching and feeder loss of 3dB, and a transmit antenna gain of 40 dB, determine the EIRP.

32.The greatest negative number which can be stored in a 8-bit register using complement arithmetic is

33.Two coupled coils have self inductances L1 =10mH and L2 = 20mH. The co-efficient of coupling (K) being 0.75 in the air. Voltage in the second coil when the current in circuit is given by I = 2 sin (314t) A is ...
a.3.14 cos (314t) V
b.3.33 sin (314t) V
c.6.66 cos (314t) V
d.6.28 cos (314t) V

34.In a radar system, if the peak transmitted power is increased by a factor of 16 and the antenna diameter is increased by a factor of 2, then the maximum range will increase by a factor of
d. 18

35.The transistor amplifier with 85% of efficiency is likely to be
a.Class A
b.Class B
c.Class AB
d.Class C

36.The modulation index of an amplitude modulated wave is changed from 0 to 1.the transmitted power is
a. Doubled
b. Halved
c.Increased by 50 percent.
d. Unchanged.

37.---------------- is defined as the time delay that a signal component of frequency w undergoes as it passes from the input to output of the system. 
a. Phase delay 
b. Group delay 
c. Frequency deviation 
d. Latency 

38. Which statement is true regarding a behavior modeling in VHDL 
a. There can be more than one process statement in an architecture which will interact concurrently 
b. Behavioral style of architecture can have only concurrent assignment statements 
c. Process is not a single concurrent statement 
d. A process need not have sensitivity list for proper implementation 

39. The process. of imitating one system with another so that the imitating systems accepts the same data, executes same programs and achieves same results as the imitated systems is known as 
a. Simulation 
b. Modification 
c. Translation 
d. Emulation 

40.As compared to a full wave rectifier using 2 diodes, the four diode bridge rectifier has the dominant advantage of 
a. Higher current carrying 
b. Lower peak inverse requirement 
c. Lower ripple factor. 
d. Higher efficiency.