Circuit card test and diagnosis using electromagnetic emission analysis

This paper describes the exploitation of spurious unwanted electromagnetic emissions from electronic circuits as a means to test and diagnose failures and performance anomalies within circuit cards and assemblies. Enhanced diagnostic capability with order-of-magnitude reduction in development and recurring costs as well as development time are likely outcomes of the successful realization of this approach. Testing is accomplished using non-contact methods providing a means to establish virtual test connectors throughout multi-layer circuit cards. Signals within electromagnetic fields that emanate across the frequency spectrum can be acquired and measured without removing protective conformal coatings. Signal propagation through the circuit card and between components is readily discernible using this technique, and the information content and intelligence contained within these signals can be used to determine the existence and the nature of faults, and probable fault location(s). Results achieved to date also indicate that electromagnetic field anomalies can reveal the existence of marginally performing components that may fail prematurely or where failure is imminent.