And because the spectrum of the discrete time signal, this same spectrum will periodically repeat if we extended the frequency greater over and above $f_s$ this kind of the spectrum shown can be the identical spectrum in each frequency band from $nf_s$ to $(n+1)f_s$ for any integer $n$. We could https://pginsector15gurugram.blogspot.com/2025/07/book-modern-pg-for-boys-in-gurgaon.html