Bifilar wound isolation network

A conductive electromagnetic interference test system for determining electromagnetic interfering source components and receptor components within a device under test at worst case electromagnetic interference conditions, said system comprising:

• a signal support system for supplying power and signal support to said device under test;
• a radio frequency signal generator for generating radio frequency signals applied to an input of said device under test;
• a measuring system coupled between said signal support system and said device under test, and being responsive to electromagnetic interference voltage signals transferred between said signal support system and said device under test;
• an isolation system having an input and an output, said input being adapted to be coupled to said device under test and said output being adapted to be coupled to said signal support system, said isolation system operating to couple signals from said signal support system to said device under test while opposing the passage of selected electromagnetic interfering voltage signals from both said device under test and said signal support system and to provide a substantially worst case impedance load for said device under test while the latter is operating in response to said signals from said signal support system, the worst case impedance load causing interfering voltage signals from said device under test to confront substantially an open circuit impedance with respect to said input of said isolation system, thereby causing said device under test to produce a worst case interference voltage signal which can be measured by said measuring system to provide a reference upon which a repeatable measure of an interference voltage signal can be determined when interference suppression techniques are supplied to rid or reduce electromagnetic interfering source and receptor components of said device under test;
• said isolation system including:
• a plurality of serially connected resonators arranged between said input and said output of said decoupling system;
• each of said resonators comprising a toroid supported along a dielectric rod;
• a single length twisted pair of electrical conductors wound around each of said toroids to form a plurality of independent yet serially interconnected inductors each having a predetermined resonant frequency, such that said isolation system has a predetermined bandwidth;
• said pair of electrical conductors allowing said isolation system to be coupled to said input of said device under test, and enabling the worst case impedance load to be provided for said device under test in order to minimize the effects of electromagnetic interference on said device under test;
• a pair of capacitors independently coupled to each of said electrical conductors and to a ground plane;
• a pair of resistors independently coupled to each of said electrical conductors and to said radio frequency signal generator;
• a first one of said inductors having a number of windings within a range of about 40-50, a second one of said inductors having a number of windings within a range of about 20-40, a third one of said inductors having a number of windings within a range of about 10-20, and a fourth one of said inductors having a number of windings within a range of about 5-15;
• and
• wherein said first inductor has a resonant frequency of about 6.4 megahertz, said second inductor has a resonant frequency of about 15.4 megahertz, and said third inductor has a resonant frequency of about 52.9 megahertz, and said fourth inductor has a resonant frequency of about 87.5 megahertz.