Unit Rectangle

$$\text{rect}(t)=\{\begin{array}{ll}1,& |t|\le \frac{1}{2}\\ 0,& \text{else}\end{array}$$ $${\text{rect}}_{\Delta }(t)=\{\begin{array}{ll}\frac{1}{\Delta },& |t|\le \frac{\Delta }{2}\\ 0,& \text{otherwise}\end{array}$$

• $\Delta$ is the rectangle width

$\mathcal{F}[\text{rect}(t/T)]=T\text{ sinc}(\omega T/2\omega )$

• Fourier Transform of rect function is Sinc Function