To reiterate that point: envision sampling the higher spectrum such the new sampling rate is at half of $f_ s1 $, suitable in the middle of the "higher frequency" spectrum components we depicted. Meaning then the spectrum centered relating to this new sampling rate ought to then be the same https://sites.google.com/view/pg-in-sector-15-gurugram/book-modern-pg-for-boys-in-gurgaon