Peak power measurement of UWB transmissions using 50-MHz bandwidth Gaussian filter

The transmit power of ultra-wideband (UWB) systems is regulated strictly to prevent interference between wireless systems. For example, the ITU-R recommendations specify the peak power spectrum density (PSD) measurement detected by a Gaussian filter with a bandwidth of 50 MHz. However, since no commercial spectrum analyzer currently has a 50-MHz bandwidth Gaussian filter, the peak PSD at 50-MHz bandwidth is estimated from a result measured at a resolution bandwidth (RBW) of 3 MHz using a conversion equation. The estimate depends heavily on the UWB modulation method and can be very different from the result detected by an ideal Gaussian filter with a 50-MHz bandwidth. We developed a new peak power measurement system with a 50-MHz bandwidth Gaussian filter to measure the peak PSD accurately without estimation. The error of the impulse bandwidth (IBW) of the measurement system is within ±5% and is sufficiently small for measuring the peak PSD of UBW transmissions.