Let the signal
$x(t)=\sum_{k=-\infty }^{+\infty } (-1)^{k} \delta (t-\frac{k}{2000})$
be passed through an LTI system with frequency response $H(\omega )$, as given in the figure below.
The fourier series representation of the output is given as
- $4000+4000\cos (2000 \pi t)+4000\cos (4000 \pi t)$
- $2000+2000\cos (2000 \pi t)+2000\cos (4000 \pi t)$
- $4000\cos (2000 \pi t)$
- $2000\cos (2000 \pi t)$