And as the spectrum of the discrete time sign, this similar spectrum will periodically repeat if we prolonged the frequency higher beyond $f_s$ these types of which the spectrum proven can be precisely the same spectrum in each individual frequency band from $nf_s$ to $(n+1)f_s$ for any integer $n$. a https://1rkflatrentgurgaonsector15.blogspot.com/2025/07/book-spacious-boys-pg-in-sector-15-part.html