Diagnostic Mapping
Measurement of the magnetic fields in close proximity to the surface of a circuit board identifies the specific locations of electromagnetic emissions. Performing near-field magnetic scanning helps engineers to locate the exact traces or components that are contributing to a failure in radiated emission testing. This process uses a small loop probe that is moved systematically over the board while the circuit is active.
The resulting map shows the intensity of the magnetic field as a function of position.
Emission Localization
Pinpointing the source of noise allows for more effective shielding and filtering strategies compared to a trial-and-error approach. High-speed clock lines and switching power supplies are common sources of these fields and often appear as hot spots on the scan. By observing how the magnetic field changes with frequency, designers can determine if the noise is a fundamental signal or a harmonic.
This information is used to optimize the layout of the board and reduce the interference with sensitive analog circuits. The technique is also useful for verifying the effectiveness of ground planes in containing electromagnetic energy.
Component Interference
Interactions between adjacent components can be visualized to prevent cross-talk or data corruption. This data confirms that the physical separation between noisy and quiet sections of the board is sufficient for stable operation.
