# EC GATE 2007 (Test 3)

Tag: ec gate 2007
Q.1
The Boolean expression  can be minimized to
A.
B.
C.
D.
Explaination / Solution:

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Q.2
An 8255 chip is interfaced to an 8085 microprocessor system as an I/O mapped I/O as show in the figure. The address lines A0 and A1 of the 8085 are used by the 8255 chip to decode internally its thee ports and the Control register. The address lines A3 to A as well as the  signal are used for address decoding. The range of addresses for which the 8255 chip would get selected is

A. F8H - FBH
B. F8GH - FCH
C. F8H - FFH
D. F0H - F7H
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Q.3
For the Op-Amp circuit shown in the figure, V is

A. -2 V
B. -1 V
C. -0.5 V
D. 0.5 V
Explaination / Solution:
No Explaination.

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Q.4
A p n junction has a built-in potential of 0.8 V. The depletion layer width a reverse bias of 1.2 V is 2 μm. For a reverse bias of 7.2 V, the depletion layer width will be
A. 4 μm
B. 4.9 μm
C. 8 μm
D. 12 μm
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Q.5
In the CMOS inverter circuit shown, if the trans conductance parameters of the NMOS and PMOS transistors are
and their threshold voltages ae   the current I is

A. 0 A
B. 25 μA
C. 45 μA
D. 90 μA
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Q.6
If R(τ) is the auto correlation function of a real, wide-sense stationary random process, then which of the following is NOT true
A.
B.
C.
D. The mean square value of the process is R(0)
Explaination / Solution:
No Explaination.

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Q.7
During transmission over a certain binary communication channel, bit errors occur independently with probability p. The probability of AT MOST one bit in error in a block of n bits is given by
A. pn
B. 1 - pn
C. np( - p)n + ( + p)n
D. 1 - (1 - p)n
Explaination / Solution:

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Q.8
A load of 50 Ω is connected in shunt in a 2-wire transmission line of Z0 = 50Ω as shown in the figure. The 2-port scattering parameter matrix (s-matrix) of the shunt element is

A.
B.
C.
D.
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Q.9
Two 4-array signal constellations are shown. It is given that φ1 and φ2 constitute an orthonormal basis for the two constellation. Assume that the four symbols in both the constellations are equiprobable. Let N0/2 denote the power spectral density of white Gaussian noise.
If these constellations are used for digital communications over an AWGN channel, then which of the following statements is true ?
A. Probability of symbol error for Constellation 1 is lower
B. Probability of symbol error for Constellation 1 is higher
C. Probability of symbol error is equal for both the constellations
D. The value of N will determine which of the constellations has a lower probability of symbol error
Explaination / Solution:
No Explaination.

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Q.10
A control system with PD controller is shown in the figure. If the velocity error constant KV =  000 and the damping ratio ζ = 0.5, then the value of KP and KD are

A. K=  00, K= 0.0
B. K=  00, K= 0.
C. K=  0, K= 0.0
D. K=  0, K= 0.