FCC Modifies PCS and AWS Power Limit Rules on Emissions and Power Limits

In a Third Report and Order released March 21, the Federal Communications Commission (FCC) has modified the rules governing broadband personal communications services (PCS) and advanced wireless service (AWS-1) to permit the use of a power spectral density model (PSD) when measuring and calculating emissions and power limits. The existing PCS and AWS-1 rules measure radiated power in terms of watts per emission and limit power output regardless of bandwidth size. In the PSD model, radiated power levels are calculated on a watts-per-MHz basis when operating with greater than one MHz of bandwidth. Also, under the existing rules, power levels are measured using peak values, while under the new rules, power levels may now be measured using average values. The more practical measurement technique will accommodate new wireless technologies that produce emissions with sub-microsecond power spikes. To prevent interference that might occur from measuring average power levels, the FCC adopted a peak-to-average ratio limit of 13 dB. Find more details at the FCC website. How are changing standards affecting test and manufacturing in the EMC industry? Hear the latest from your colleagues by visiting the Testing Community Forums.