Answer to Question #61219 in Electrical Engineering for KIM ANNA
Derive the Fourier Transform of a rectangular pulse by
a) Differentiating the pulse to form two delta functions
b) Fourier Transforming the derivative
c) Integrating in the frequency domain by dividing by j2πf
Repeat this procedure for the triangle function using a double derivative.
Hence or otherwise, show that if a function has discontinuities in the nth derivative, the sidelobes will fall off as 1/(f^(n+1)).