Royce Sumagaysay ECE - 4
Module 7
1. Given two complex numbers: C1=2-3i, and C2=1+4i. The product P=C1*C2 can be computed
as
A. 2+5i
B. -10+5i
C. -14+5i
D. 14+5i
Solution The correct answer is (D).
P = C1 x C2 P = 2 + 5i + 12
= (2 3i) (1+ 4i) = 14 + 5i
= 2 + 8i 3i 12i2
2. Given the complex number C1=3+4i. In polar coordinates, the above complex number can be
expressed as C1=Aei , where A and is called the amplitude and phase angle of C1,
respectively. The amplitude A can be computed as
A. 3
B. 4
C. 5
D. 7
Solution
The correct answer is (C).
Given
C1 = 3 + 4i = Ae(i )
A = Amplitude
=32 + 42
=5
3. Which of the following is an even function of t ?
A. t2
B. t 2 4t
C. sin(2t) + 3t
D. t3+6
Solution
The correct answer is (A).
4. A periodic function is given by a function which
A. has a period T = 2
B. satisfies f (t + T ) = f (t)
C. satisfies f (t + T ) = f (t)
D. has a period T =
Solution
The correct answer is (B).
5. Given the following periodic function, f (t) .
The coefficient a0 of the continuous Fourier series associated with the above given
function f (t) can be computed as
8
A.
9
16
B.
9
24
C.
9
32
D.
9
Solution
The correct answer is (B).
The coefficient a0 of the continuous Fourier series associated with the given function f (t ) can
be computed as (see Eq. 2, in Chapter 11.02)
a 1
0 = {f (t) dt}
1 2
2
6
a0 = t dt + ( t + 6)dt
6 0 2
2
1t 3 t2 6
a0 = + + 6 t
6 3 0 2 2
a0 = 1.78
6. Forward and inverse Fourier transforms exist for samples having values
A. integers
B. finite
C. infinite
D. discrete
Answer
C
7. In Fourier series expansion, An will zero for _______ function and will be zero for
_______ function.
A. odd, odd
B. odd, even
C. even, odd
D. even, even
ANSWER
B
8. The inverse Fourier transform of product of two time functions [f1()f2()] is given by :
A. [f1(t) + f2(t)]
B. [f1(t) * f2(t)]
C. [f1(t) / f2(t)]
D. [f1(t) x f2(t)]
ANSWER
9. The Fourier transform of product of two time functions [f1(t)f2(t)] is given by :
A. [f1() + f2()]
B. [f1() / f2()]
C. [f1() * f2()]
D. [f1() x f2()]
Answer
C
10. The magnitude spectrum of a Fourier transform of a real-valued time signal has _______
symmetry.
A. No
B. Odd
C. Even
D. Conjugate
Answer
C
Module 8
1. Which of the following is the first method proposed for design of FIR filters?
A. Chebyshev approximation
B. Frequency sampling method
C. Windowing technique
D. None of the mentioned
Answer
C
2. In frequency sampling method, transition band is a multiple of which of the
following?
A. /M
B. 2/M
C. /2M
D. 2M
Answer
B
3. Which of the following values can a frequency response take in frequency sampling
technique?
A. Zero
B. One
C. Either of them
D. None of the mentioned
Answer
C
4. Which of the following is the correct expression for transition band f?
A. (p- s)/2
B. (p+s)/2
C. (p.s)/2
D. (s- p)/2
Answer
D
5. What is the range of values called as to which the amplitudes of the output during a
limit cycle ae confined to?
A. Stop band
B. Pass band
C. Live band
D. Dead band
Answer
D
6. The limit cycle mode with zero input, which occurs as a result of rounding the
multiplications, corresponds to an equivalent second order system with poles at z=1.
A. True
B. False
Answer
A
7. What is the necessary and sufficient condition for a second order filter that no zero-
input overflow limit cycles occur?
A. |a1|+|a2|=1
B. |a1|+|a2|>1
C. |a1|+|a2|<1
D. None of the mentioned
Answer
C
8. What is the tool used in tasks such as zooming, shrinking, rotating, etc.?
A. Sampling
B. Interpolation
C. Filters
D. None of the Mentioned
Answer
B
9. The type of Interpolation where the intensity of the FOUR neighbouring pixels is
used to obtain intensity a new location is called ___________
A. cubic interpolation
B. nearest neighbour interpolation
C. bilinear interpolation
D. bicubic interpolation
Answer
B
10. Dynamic range of imaging system is a ratio where the upper limit is determined by
A. Saturation
B. Noise
C. Brightness
D. Contrast
Answer
A
Module 9
1. The roots of the polynomial H(z) are identical to the roots of the polynomial H(z -1).
A. True
B. False
Answer
A
2. The roots of the equation H(z) must occur in:
A. Identical
B. Zero
C. Reciprocal pairs
D. Conjugate pairs
Answer
C
3. What is the number of filter coefficients that specify the frequency response for h(n)
symmetric?
A. (M-1)/2 when M is odd and M/2 when M is even
B. (M-1)/2 when M is even and M/2 when M is odd
C. (M+1)/2 when M is even and M/2 when M is odd
D. (M+1)/2 when M is odd and M/2 when M is even
Answer
D
4. Which of the following is not suitable either as low pass or a high pass filter?
A. h(n) symmetric and M odd
B. h(n) symmetric and M even
C. h(n) anti-symmetric and M odd
D. h(n) anti-symmetric and M even
Answer
C
5. The anti-symmetric condition is not used in the design of low pass linear phase FIR
filter.
A. True
B. False
Answer
A
6. In IIR Filter design by the Bilinear Transformation, the Bilinear Transformation is a
mapping from
A. Z-plane to S-plane
B. S-plane to Z-plane
C. S-plane to J-plane
D. J-plane to Z-plane
Answer
B
7. In Bilinear Transformation, aliasing of frequency components is been avoided.
A. True
B. False
Answer
A
8. In the Bilinear Transformation mapping, which of the following are correct?
A. All points in the LHP of s are mapped inside the unit circle in the z-plane
B. All points in the RHP of s are mapped outside the unit circle in the z-plane
C. Both a & b
D. None of the mentioned
Answer
C
9. A direct partial-fraction expansion of the transfer function in Z leads to
A. The parallel form II structure
B. The parallel form I structure
C. Cascaded structure
D. None of the above
Answer
A
10. Which of the following is a representation of system function?
A. Normal system function
B. Laplace transform
C. Rational system function
D. All of the mentioned
Answer
D
