Permissive Changes against Full Retest after a Firmware Update
Firmware updates altering output power, channels, or DFS logic trigger mandatory permissive change filings or retests before distribution.
Eirp Verification
Meaning
Measurement procedures confirm the total power radiated by an antenna system in a specific direction. Technicians use eirp verification to ensure that the combination of transmitter output and antenna gain stays within legal limits for a specific region. This process accounts for cable losses and connector attenuations that occur between the radio module and the radiator.
The check fails if the measured energy exceeds the threshold defined by the local regulator.
Measurement Protocol
Test engineers perform these checks inside an anechoic chamber to prevent external signals from skewing the results. During eirp verification, the device rotates through multiple axes while a calibrated probe captures the peak signal strength. These data points form a three dimensional map of the radiation pattern.
Precise positioning is required to avoid null points in the field. The setup must be calibrated with a standard gain horn before the actual device testing begins.
System Efficiency
Higher antenna gain often requires a reduction in conducted power to maintain the same radiated level. Because eirp verification measures the final output, it reveals how well the integration of the RF front end performs. Mismatched impedances at the board interface will lower the final reading.
This drop indicates energy lost as heat rather than signal.
Power Limit
Regulators set strict caps on energy density. Compliance depends on these final figures.