Re: Difference between a 475 and a 475A


Dr. Lee, and Harvey White,

Thanks for the informative responses, that does make more sense, especially in light of an impulse input, which I understand implies a broad spectrum of underlying frequencies including very high frequencies (in order to reconstruct the impulse from the elements of the Fourier decomposition). Those high frequencies, which are required to get a good steep rise time, will also show up as high frequency ringing after the rise and fall, which messes up the fidelity to the overall shape of the pulse.

This also makes sense to me from a mechanical analog to the electrical signal: if you have a damped spring system you can either get fast changes in the displacement, but have lots of wiggling afterwards, or you can have very little wiggling but the displacement is slowed down a lot. A loose piston attached to the spring lets the spring change length very quickly, but doesn't do much to damp overshoot and undershoot or to dissipate the energy in the spring after the change in length, but a stiff piston which will rapidly stop the under/overshoot will also make it much harder and slower the change the length of the spring.

Join to automatically receive all group messages.