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& = \frac{1}{2j} e^{j6\pi t} - \frac{1}{2j} e^{-j6\pi t} \\ | & = \frac{1}{2j} e^{j6\pi t} - \frac{1}{2j} e^{-j6\pi t} \\ | ||
& \text{By Fourier Series we know that} \sum_{k=-\infty}^\infty a_k e^{jk\omega_o t} \\ | & \text{By Fourier Series we know that} \sum_{k=-\infty}^\infty a_k e^{jk\omega_o t} \\ | ||
− | & \text{Here, } \omega_o = 6 \pi \text{ therefore, } | + | & \text{Here, } \omega_o = 6 \pi \text{ ,therefore, } \\ |
& = \frac{1}{2j} e^{j\omega_o(1) t} - \frac{1}{2j} e^{-j\omega_o(2) t} \\ | & = \frac{1}{2j} e^{j\omega_o(1) t} - \frac{1}{2j} e^{-j\omega_o(2) t} \\ | ||
+ | & \text{So we can say that} a_1 = \frac{1}{2j}, a_{-1} = -\frac{1}{2j} \\ | ||
2) x(t) = 2 + cos(6 \pi t) - \frac{1}{2} sin(3 \pi t), \omega_{o} = 3\pi \\ | 2) x(t) = 2 + cos(6 \pi t) - \frac{1}{2} sin(3 \pi t), \omega_{o} = 3\pi \\ | ||
3) x(t) = cos(\frac{2\pi}{10}t), \omega_{o} = \frac{\pi}{10} \\ | 3) x(t) = cos(\frac{2\pi}{10}t), \omega_{o} = \frac{\pi}{10} \\ |
Revision as of 02:28, 26 April 2019
A project by Kalyan Mada
Introduction
I am going to compute some fourier series coefficients.
CT signals
$ \begin{align} \bar 1) x(t) = sin(6 \pi t), \omega_{o} = 6\pi \\ & = \frac{e^{j6\pi t} - e^{-j6\pi t} }{2j} \\ & = \frac{1}{2j} e^{j6\pi t} - \frac{1}{2j} e^{-j6\pi t} \\ & \text{By Fourier Series we know that} \sum_{k=-\infty}^\infty a_k e^{jk\omega_o t} \\ & \text{Here, } \omega_o = 6 \pi \text{ ,therefore, } \\ & = \frac{1}{2j} e^{j\omega_o(1) t} - \frac{1}{2j} e^{-j\omega_o(2) t} \\ & \text{So we can say that} a_1 = \frac{1}{2j}, a_{-1} = -\frac{1}{2j} \\ 2) x(t) = 2 + cos(6 \pi t) - \frac{1}{2} sin(3 \pi t), \omega_{o} = 3\pi \\ 3) x(t) = cos(\frac{2\pi}{10}t), \omega_{o} = \frac{\pi}{10} \\ 4) x(t) = \begin{cases} 3, & \text{if}\ a=1 \\ 0, & \text{otherwise} \end{cases} \end{align} $
DT signals
$ \begin{align} x[n] = 1 + sin(\frac{2\pi}{8}n) + 3cos(\frac{2\pi}{8}n), N=8 --> \omega_{o} = \frac{2\pi}{8} \\ x[n] = -j^n, \omega_o = \frac{\pi}{2} \\ x[n] = \begin{cases} sin(\pi t), & \text{if}\ a=1 \\ 0, & \text{otherwise} \end{cases}\\ x[n] = \begin{cases} 4, & \text{if}\ a=1 \\ -4, & \text{otherwise} \end{cases} \end{align} $
Questions and comments
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[to 2019 Spring ECE 301 Boutin]