Fourier transform of the signal x(n) = u(n – k) is:
1
\(\frac{{{e^{j\omega k}}}}{{1 - {e^{j\omega }}}}\)
2
\(\frac{{{e^{ - j\omega k}}}}{{1 + {e^{j\omega }}}}\)
3
\(\frac{{{e^{ - j\omega k}}}}{{1 - {e^{ - j\omega }}}}\)
4
\(\frac{{{e^{j\omega k}}}}{{1 + {e^{j\omega }}}}\)