# System Analysis using Fourier Series & Transform (C.T) - MCQs

## System Analysis using Fourier Series & Transform (C.T) - MCQs

1. Which are the only waves that correspond/ support the measurement of phase angle in the line spectra?

a. Sine waves
b. Cosine waves
c. Triangular waves
d. Square waves

2. Double-sided phase & amplitude spectra _____

a. Possess an odd & even symmetry respectively
b. Possess an even & odd symmetry respectively
c. Both possess an odd symmetry
d. Both possess an even symmetry

ANSWER: a. possess an odd & even symmetry respectively

3. What does the first term 'a0' in the below stated expression of a line spectrum indicate ?

x(t) = a0 + a1 cos w0 t + a2 cos2 w0t +......+ b1 sin w0 t + b2 sin w0 t + .....

a. DC component
b. Fundamental component
c. Second harmonic component
d. All of the above

4. Which kind of frequency spectrum/spectra is/are obtained from the line spectrum of a continuous signal on the basis of Polar Fourier Series Method?

a. Continuous in nature
b. Discrete in nature
c. Sampled in nature
d. All of the above

5. Which type/s of Fourier Series allow/s to represent the negative frequencies by plotting the double-sided spectrum for the analysis of periodic signals ?

a. Trigonometric Fourier Series
b. Polar Fourier Series
c. Exponential Fourier Series
d. All of the above

6. What does the signalling rate in the digital communication system imply ?

a. Number of digital pulses transmitted per second
b. Number of digital pulses transmitted per minute
c. Number of digital pulses received per second
d. Number of digital pulses received per minute

ANSWER: a. Number of digital pulses transmitted per second

7.As the signalling rate increases, _______

a. Width of each pulse increases
b. Width of each pulse decreases
c. Width of each pulse remains unaffected
d. None of the above

ANSWER: b. Width of each pulse decreases

8. Which phenomenon occurs due to an increase in the channel bandwidth during the transmission of narrow pulses in order to avoid any intervention of signal distortion?

a. Compression in time domain
b. Expansion in time domain
c. Compression in frequency domain
d. Expansion in frequency domain

ANSWER: d. Expansion in frequency domain

9. Why are the negative & positive phase shifts introduced for positive & negative frequencies respectively in amplitude and phase spectra?

a. To change the symmetry of the phase spectrum
b. To maintain the symmetry of the phase spectrum
c. Both a & b
d. None of the above

ANSWER: b. To maintain the symmetry of the phase spectrum

10. Duality Theorem / Property of Fourier Transform states that _________

a. Shape of signal in time domain & shape of spectrum can be interchangeable

b. Shape of signal in frequency domain & shape of spectrum can be interchangeable

c. Shape of signal in time domain & shape of spectrum can never be interchangeable

d. Shape of signal in time domain & shape of spectrum can never be interchangeable

ANSWER: a. Shape of signal in time domain & shape of spectrum can be interchangeable

11. Which property of fourier transform gives rise to an additional phase shift of -2π ftd for the generated time delay in the communication system without affecting an amplitude spectrum ?

a. Time Scaling
b. Linearity
c. Time Shifting
d. Duality

12. Which among the below assertions is precise in accordance to the effect of time scaling ?

A : Inverse relationship exists between the time and frequency domain representation of signal

B : A signal must be necessarily limited in time as well as frequency domains

a. A is true & B is false
b. A is false & B is true
c. Both A & B are true
d. Both A & B are false

ANSWER: a. A is true & B is false

13. Which is/are the mandatory condition/s to get satisfied by the transfer function for the purpose of distortionless transmission?

a. Amplitude Response should be constant for all frequencies

b. Phase should be linear with frequency passing through zero

c. Both a & b

d. None of the above