Managing Dual Band Radio Laboratory Testing under Chinese Regulatory Frameworks
SRRC approval for dual-band radios demands locked firmware power tables, local agent coordination, and strict host radiated spur compliance to avoid re-test delays.
2.4 GHz EIRP Limits
Meaning
Regulatory boundaries establish the maximum power that a transmitter can radiate in the most efficient direction of its antenna. Under standard conditions, 2.4 ghz eirp limits restrict wireless modules to a total effective radiated power of thirty-six decibel-milliwatts, or four watts, in FCC jurisdictions when utilizing point-to-multipoint topologies. This cap ensures that adjacent devices operate without destructive mutual interference.
Regulatory Threshold
Rules published by regional authorities dictate different levels based on application and geographic market. For instance, the European Telecommunications Standards Institute restricts the 2.4 ghz eirp limits to twenty decibel-milliwatts for wideband modulation systems operating in this band. Designers must adjust the internal transmitter output to compensate for the specific gain of the attached antenna.
If a high-gain antenna is chosen, the conducted power must be decreased accordingly.
Hardware Impact
Attenuation circuits or firmware-locked power tables prevent the completed assembly from exceeding the certified levels during operation. When a system integrator pairs an off-the-shelf radio module with a custom cabling run and a directional antenna, the total output must remain within the 2.4 ghz eirp limits under all software configurations. This restriction influences the selection of the low-noise block and the physical trace routing of the radio-frequency front end.
Excessive board-level losses can sometimes help meet these criteria, though they reduce overall receiver sensitivity.
Compliance Verification
Testing laboratories evaluate the fully integrated device in an anechoic chamber to confirm that the radiated power matches the declared values. The measurement process sweeps the antenna through a complete sphere to locate the peak radiation intensity. In situations where the assembly is found to violate the 2.4 ghz eirp limits, the firmware must be modified to apply a permanent attenuation offset.
Once these measurements are completed and documented in the official test report, the product can receive its regulatory mark for market entry.