Abstract: A method and apparatus for use in designing and evaluating filters to resolve undesired signal transmission in a device including, without limitation, EMI filters for suppressing an identified EMI in a device under test in a particular application. The complex impedance of the source impedance presented to the filter and the load impedance presented to the filter are separately determined over a frequency range of interest. The impedances are used to determine a complex power flow of the device under test without the filter. The power flow is used to identify frequencies corresponding to the undesired signal transmission. A filter is then designed or selected, based upon the complex impedances of the filter load impedance and filter source impedance at the identified resonant frequencies, to attenuate the identified resonances or undesired signal transmission over each frequency range of interest.

Abstract: A multi-channel electromagnetically transparent voltage probe transmission link system for monitoring a plurality of voltage signals at a plurality of test points of a device under test that is subjected to a radiation field. Each channel includes two voltage probes, an electrical to optical signal transmitter, an optical signal transmission line and a receiver located out of the radiation field. The voltage probes contact and sense the voltage signals at the test point. The electrical to optical transmitters are removably mounted in a common base and are powered by either a common (or shared) power supply and/or by dedicated power supplies, such as rechargeable batteries. The receivers process the optical signals and provide display signals corresponding to the sensed voltage signal at the plurality of test points for evaluating the effect of the test radiation field.