Ferrite beads are a very low cost and easy way to add high frequency isolation loss in a circuit without a power loss at DC and low frequencies. Ferrite beads are most effective at frequencies in excess of 1.0 Mhz. When these are used with the appropriate parallel capacitance, they provide high frequency decoupling and parasitic suppression. A brief paper on ferrite beads has been released by Signal Processing Group Inc and may be found at http://www.signalpro.biz>>engineer’s corner.