FCC modifies UWB measurement procedures
Staff -- Test & Measurement World, 4/1/2005
On March 10, the Federal Communications Commission (FCC) announced that it has adopted a waiver of its emission measurement procedures for ultra-wideband (UWB) transmission systems. As a result of the waiver, radiated emissions from UWB transmitters may now be measured while the transmitter is in its normal operating mode.
The FCC granted the waiver in response to a petition filed by the MultiBand OFDM Alliance Special Interest Group. The waiver should provide greater flexibility for companies designing UWB devices.
Because UWB devices operate on the same frequency bands used by licensed stations, the FCC had previously established a conservative procedure for measuring their RF emissions. UWB transmitters that employ frequency-hopping techniques had to be measured with the hop stopped and the transmitter operating in a continuous mode; UWB transmitters that gate the emissions on and off had to be measured with the emissions gated on. Both procedures could result in measured emission levels that were greater than the UWB signal levels under actual operation.
With the waiver, which applies only to indoor or handheld UWB devices, the FCC now permits emissions from UWB transmitters to be measured when the transmitter is operating normally. The FCC concluded that these tests would not result in increased harmful interference to licensed radio operations, but the UWB devices may not operate within the 5030–5650-MHz band used for aircraft landing systems and for weather radars. www.fcc.gov.
