Meaning
Spatial normalization data defines the field uniformity across an electromagnetic test zone during immunity qualification. This radiated immunity calibration file documents the power levels required to achieve a target field strength at specific frequency intervals. It governs the reference relationship between amplifier output and antenna input by establishing a verified baseline prior to the introduction of a device.
A laboratory excludes the subject hardware during this procedure to isolate the field characteristics of the chamber from the loading effects of the equipment under test.
Calibration Procedure
Signal generators sweep through the frequency spectrum to record the amplitude settings needed to maintain a constant volt per meter value. Technicians monitor the forward and reflected power at each step to account for cable losses and antenna gain variations. Every entry inside the table provides the reference power level for the corresponding frequency band.
System software subsequently applies these values to ensure that the test signals reach the required intensity without exceeding equipment safety limits.
Verification Requirement
Periodic audits of the data ensure that the test environment remains stable over the operational life of the chamber. Modifications to the physical layout or the replacement of antenna cables necessitate a new capture of field strength metrics to prevent invalid test results. Any shift in the ambient environment alters the transmission path and requires a fresh verification to maintain compliance with relevant standards.
Integration Constraint
Manufacturers utilize the stored parameters to automate the leveling of signals during the compliance verification of electronic subassemblies. Accurate implementation of the file prevents the under-testing of boards that exhibit high sensitivity to narrow band interference. Correct application of the data ensures that the electromagnetic stress applied to the product matches the intended certification level throughout the entire duration of the immunity sweep.
