## 1.4. UWB SignalsAs defined by the FCC's First Report and Order, UWB signals must have bandwidths of greater than 500 MHz or a fractional bandwidth larger than 20 percent at all times of transmission [3]. Fractional bandwidth is a factor used to classify signals as narrowband, wideband, or ultra-wideband and is defined by the ratio of bandwidth at 10 dB points
Equation 1-4 where f Equation 1-5 ## Figure 1-5. A 500-picosecond Gaussian monocycle in (a) the time domain and (b) the frequency domainwhere t represents time and t is a time decay constant that determines the temporal width of the pulse. As shown in Figure 1-5, a 500-picosecond pulse generates a large bandwidth in the frequency domain with a center frequency of 2 GHz. In Figure 15b, the lowest and highest cutoff frequencies at 10 dB are approximately 1.2 GHz and 2.8 GHz, respectively, which lead to a fractional bandwidth of 80 percent; this is much larger than the minimum B Here is the classification of signals based on their fractional bandwidth:
For example, 802.11 and Bluetooth have fractional bandwidths of 0.8 percent and 0.04 percent, respectively. |

Ultra-Wideband Communications: Fundamentals and Applications

ISBN: 0131463268

EAN: 2147483647

EAN: 2147483647

Year: 2005

Pages: 93

Pages: 93

Authors: Faranak Nekoogar

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