Electronic – Ferrite Bead Simulation in SPICE

It really isn't all that critical. The bead is being used as a choke to prevent unwanted VHF parasitic oscillations. Any bead in your junkbox should be fine.

Overshoot (and undershoot as used by the TS, which is essentially negative overshoot) are created by a quick transition of the signal (arriving through a long wire) arriving at the end of the line with no place to go (read: arriving at a high impedance). Hence there are three basic ways to reduce overshoot:

• make the wire short
• make the edge (transition) less abrubt (a series resistor at the source will do this)
• give the signal edge somewhere to go (a parallel resistor at the destination will do this, a series resistor will have some effect, but less).

A ferrite bead will soften the edge a little bit, but it is mainly used to prevent HF signals (like from radio stations) from entering a device, and vice versa to prevent HF signals from the device from entering the cable which would work as an antenna for these (highly unwanted) signals. HF in this sense means higher than the frequencies you are likely to look at.

edit/added:

A series resistor will be more effective at the source, but it will flatten the edge, which might be undesirable. A parallel resistor (to ground or power, or a combination) will be more effective at the receiving end, and will not harm the edge, but it will attenuate (lower) the received voltage, and increase power consumption. Note that to be effective the resistors must match the cable impedance. Something in the order of 30 .. 100 Ohms is a good guess.