7.2. 1 Windows function method o Our objective is to find a finite-duration impulse response sequence thin] of length 2M+1 whose DTFT Ht(ejd) approximates the desired dTFT Hd(ejo) in some sense7.2.1 Windows function method  Our objective is to find a finite-duration impulse response sequence {ht[n]} of length 2M+1 whose DTFT Ht(ejω) approximates the desired DTFT Hd(ejω) in some sense