sinc function fourier transform pair
hi we know that
F \[\frac{\sin(Wt)}{\pi t}\] is \[rect(\frac{\omega}{2W})\]
and also we know that multiplication in time domain is convolution in frequency domian. i.e.,
\[x(t)\times h(t) \longarrow \frac{1}{2 \pi}X(j\omega)*H(j\omega)\]
using \[h(t) = x(t)\] we get
\[x^2(t) \longarrow \frac{1}{2\pi}X(j\omega)*X(j\omega)\]
For us \[x(t) = \frac{\sin(1000 \pit)}{\pi t}\]
Thus the FT of \[\frac{\sin^{2}(Wt)}{(\pi t)^{2}}\] turns out to be \[1000 tri(\frac{\omega}{2000 pi})\]. Hope this helps you
thnx
purna!
Added after 2 minutes:
hi we know that
F.T. of \[\frac{\sin(Wt)}{\pi t}\] is \[rect(\frac{\omega}{2W})\]
and also we know that multiplication in time domain is convolution in frequency domian. i.e.,
\[x(t)\times h(t) ---> \frac{1}{2 \pi}X(j\omega)*H(j\omega)\]
using \[h(t) = x(t)\] we get
\[x^2(t) ---> \frac{1}{2\pi}X(j\omega)*X(j\omega)\]
For us \[x(t) = \frac{\sin(1000 \pit)}{\pi t}\]
Thus the FT of \[\frac{\sin^{2}(Wt)}{(\pi t)^{2}}\] turns out to be \[1000 tri(\frac{\omega}{2000 \pi})\]. Hope this helps you
thnx
purna!
Added after 1 minutes:
hi we know that
F.T. of \[\frac{\sin(Wt)}{\pi t}\] is \[rect(\frac{\omega}{2W})\]
and also we know that multiplication in time domain is convolution in frequency domian. i.e.,
\[x(t)\times h(t) ---> \frac{1}{2 \pi}X(j\omega)*H(j\omega)\]
using \[h(t) = x(t)\] we get
\[x^2(t) ---> \frac{1}{2\pi}X(j\omega)*X(j\omega)\]
For us \[x(t) = \frac{\sin(1000 \pit)}{\pi t}\]
Thus the FT of \[\frac{\sin^{2}(1000 \pi t)}{(\pi t)^{2}}\] turns out to be \[1000 tri(\frac{\omega}{2000 \pi})\]. Hope this helps you
thnx
purna!
Added after 30 seconds:
hi we know that
F.T. of \[\frac{\sin(Wt)}{\pi t}\] is \[rect(\frac{\omega}{2W})\]
and also we know that multiplication in time domain is convolution in frequency domian. i.e.,
\[x(t)\times h(t) ---> \frac{1}{2 \pi}X(j\omega)*H(j\omega)\]
using \[h(t) = x(t)\] we get
\[x^2(t) ---> \frac{1}{2\pi}X(j\omega)*X(j\omega)\]
For us \[x(t) = \frac{\sin(1000 \pi t)}{\pi t}\]
Thus the FT of \[\frac{\sin^{2}(1000 \pi t)}{(\pi t)^{2}}\] turns out to be \[1000 tri(\frac{\omega}{2000 \pi})\]. Hope this helps you
thnx
purna!