when the boxcar y value is 1X(jω)=2T1sin(ωT1)ωT1X(j\omega) = 2T_1\frac{sin(\omega T_1)}{\omega T_1}X(jω)=2T1ωT1sin(ωT1)We don’t eliminate parent and child T1T_1T1 because of 0 value approximation