Frequency Response and Rise Time

A Fourier analysis of a square wave waveform will show that the composition is made of the odd harmonic of the fundamental frequency of sine waves. A (sin x)/x relationship shows that when the rise time is shorter, higher bandwidth is needed. Typical margins for error when measuring time domain parameters are for the system Tr to be 1/3 the expected device Tr for ~ 5% error.      1/7 the expected Tr for ~ 1% error.

Tr = (0.35)/bandwidth     and      Bw = (0.35)/Tr