Meaning
Quantified indices comparing measured radiation levels to the regulatory limits serve to evaluate multi-transmitter devices. The exposure ratio is calculated by dividing the measured radiation value by the corresponding maximum allowed exposure limit.
Multiple Transmitter Evaluation
Handsets using several antennas simultaneously must not exceed cumulative radiation thresholds. Calculating the exposure ratio for each active transmitter ensures that the total emissions do not exceed safety levels. This calculation adds the individual ratios together, where a sum below one indicates compliance.
Device Certification
Regulatory bodies demand documented evidence of simultaneous-transmission compliance for complex communication hardware. The calculated exposure ratio is a key part of the test report for multi-band modules. Safety margins must be maintained across all frequency combinations to guarantee that the hardware remains compliant under all operating conditions.
Software Algorithm
Real-time power monitoring is used by modern modems to manage the emissions dynamically during operation. If the calculated exposure ratio approaches the limit, the device firmware triggers a reduction in transmitter power. This system ensures that high data rates can be maintained on one link while another link is active, optimizing the overall throughput of the system.
In practice, the power management algorithm uses a sliding window to calculate the average exposure, preventing premature throttling of the transmit power and ensuring a stable connection.
