A fresh set of 20 random questions is generated every time you open this page and every time you refresh it.For each of the following multiple choice questions, choose the most appropriate answer :
1. The signal defined by the equations f(t) = 0 for t < 0, f(t) = E for 0 ? t ? a and f(t) = 0 for t > a is
A. a step function
B. a pulse function
C. a shifted step function originating at t = a
D. unit step function
2. All causal systems must have the component of
A. memory
B. time invariance
C. stability
D. linearity
3. Under which conditions does an initially relaxed system become unstable ?
A. only if bounded input generates unbounded output
B. only if bounded input generates bounded output
C. only if unbounded input generates unbounded output
D. only if unbounded input generates bounded output
4. If f(t) is an even function, the coefficients Fn in the exponential form of Fourier series
A. are real
B. are imaginary
C. are complex
D. may be real or imaginary
5. A signal g(t) = A then g(t) is a
A. energy signal
B. power signal
C. neither energy nor power signal
D. insufficient data
6. Generally, the convolution process associated with the Laplace Transform in time domain results into________
A. Simple multiplication in complex frequency domain
B. Simple division in complex frequency domain
C. Simple multiplication in complex time domain
D. Simple division in complex time domain
7. In RLC circuits the state variables generally selected are
A. voltages across capacitors
B. currents through resistances and voltages across capacitors
C. currents through resistances and capacitances
D. currents through inductances and voltages across capacitances
8. For a second order system, damping ratio ? is such that 0 < ? <. Then the roots of characteristic equation are
A. real but not equal
B. imaginary
C. complex conjugate
D. real and equal
9. Two rectangular waveforms of duration t1 and t2 seconds are convolved. What is the shape of the resulting waveform?
A. Triangular
B. Trapezoidal
C. Rectangular
D. Semi-circular
10. A time invariant system is a system whose output
A. vanishes with a delay in input
B. remains same with a delay in input
C. decreases with a delay in input
D. increases with a delay in input
11. A system is said to be defined as non causal, when
A. the output at the present depends on the input at an earlier time
B. the output at the present does not depend on the factor of time at all
C. the output at the present depends on the input at the current time
D. the output at the present depends on the input at a time instant in the future
12. Which of the following is/are not a property/properties power spectral density function Sx(?)?
A. Sx(?) is real function of ?
B. Sx(?) is a even function of ?
C. Sx(?) is a odd function of ?
D. Sx(?) is non-positive function of ?Sx(?) ? 0 for all ?
13. Which one of the following is correct? Energy of a power signal is
A. finite
B. zero
C. infinite
D. Zero to Infinity
14. What is the value of an area under the conditional PDF ?
A. Greater than 0 but less than 1
B. Greater than 1
C. Equal to 1
D. Infinite
15. The _____ of a composite signal is the difference between the highest and the lowest frequencies contained in that signal
A. frequency
B. period
C. bandwidth
D. amplitude
16. What does the spectral density function of any signal specify?
A. Distribution of energy or power
B. Consumption of energy or power
C. Conservation of energy or power
D. Generation of energy or power
17. Which property of fourier transform gives rise to an additional phase shift of -2? 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
18. Double integration of a unit step function would lead to
A. an impulse
B. a parabola
C. a ramp
D. a doublet
19. FIR digital filter having __________ stability than FIR filter.
A. good stability
B. poor stability
C. stability not guarnteed
D. poor stability
20. The ESD of a real valued energy signal is always ________
A. An even (symmetric) function of frequency
B. An odd (non-symmetric) function of frequency
C. A function that is odd and half-wave symmetric
D. None of the above
Dr K Chaudhry 5 Alpha Inmternational City, Fatehabad 125050 M: 9810570740, 9810571993facebook.com/doctorkc