As you requires I am here giving you last year placement paper of Indian Space Research Organization (ISRO).

ISRO Placement Paper

1.In an amplitude modulated system if the total power is 600W and the power in the carrier is 400W, the modulation index is
a.-0.5
b.0.75
C.0.9
d.1

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.
a.2.3um
b.1.29um
c.1.5um
d.3.24um

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
a.3cos(irn/4)
b.3cos(nn/2)
c.3cos(7rn)
d.3 cos(nnn/3 )

7.In VHDL all the statements written inside a process statement are
a.Concurrent
b.Sequential
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
a.0.4
b.2
c.10
d.4

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
a.1.65
b.1.45
c.1
d.1.21

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
d.QPSK

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
a.2500W
b.250W
c.500W
d.2000W

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