Which one of the following is a periodic signal?
A. $${x_1}\left( t \right) = 2{e^{j\left( {t + \frac{\pi }{4}} \right)}}u\left( t \right)$$
B. $${x_2}\left( n \right) = u\left[ n \right] + u\left[ { - n} \right]$$
C. $${x_3}\left[ n \right] = \sum\limits_{k = - \infty }^\infty {\left\{ {\delta \left[ {n - 4k} \right] - \delta \left[ {n - 1 - 4k} \right]} \right\}} $$
D. $${x_4}\left( t \right) = {e^{\left( { - 1 + j} \right)t}}$$
Answer: Option C
This Question Belongs to Electronics And Communications Engineering >> Signal Processing
The Fourier transform of a real valued time signal has
A. Odd symmetry
B. Even symmetry
C. Conjugate symmetry
D. No symmetry
A. $$V$$
B. $${{{T_1} - {T_2}} \over T}V$$
C. $${V \over {\sqrt 2 }}$$
D. $${{{T_1}} \over {{T_2}}}V$$
A. $$T = \sqrt 2 {T_s}$$
B. T = 1.2Ts
C. Always
D. Never
A. $${{\alpha - \beta } \over {\alpha + \beta }}$$
B. $${{\alpha \beta } \over {\alpha + \beta }}$$
C. α
D. β
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