d by (1/duty-cycle). By gating out the noise pseudo-random time sequence. Another method is to except during the interval of the expected incoming send the pulse with or without inversion. In both cases pulse, the signal-to-noise ratio will only be a function of the correlation of the received pulse with a "template" the power in the pulse, regardless of the duty cycle. An pulse generated in the receiver will result in a different example may make the explanation clearer. Let's say we polarity, depending on whether a "1" or a "0" was are sending data a rate of 10 Mbps. A UWB pulse in the transmitted. transmitter is 200 picoseconds wide; 20 pulses represent Detection of UWB bits is illustrated in Figure 5.2-30. one bit. The time between bits is 1/(10*106) = 100 A "1" monopulse is represented by a negative line nanoseconds. So the time between pulses is (100 ns) followed by a positive line, and a "0" monopulse by /20 = 5 ns. The duty cycle is (200 ps), (5 ns) = 25. Now the inverse-a positive line and a negative line. The the processing gain attributed to the number of UWB RANDOM DATA Magnified Trace 31 PN Sequence ck Single Pulse 4th Order 3.6 8.4 Hz Impulse Generator Bessel Bandpass 39 39.2 Time (sec) OUTPUT Pulse Train Time (nsec) Spectrum Analyzer Display OUTPUT Spectrum Analyzer Frequency (GHz) Figure 5.2-29 Simulated sequence of UWB pulses. CHAPTER 5.2 Short-range wireless applications and technologies RECEIVED SIGNAL LOCAL TEMPLATE CORRELATOR OUTPUT LOGIC OUTPUT Figure 5.2-30 Detection of UWB bit sequence. pulses per bit is 10log(20) = 13 dB. That due to the duty for using UWB in Europe are also being considered by the cycle is 10log(25) = 14 dB. Total processing gain is European Union. Due to the fear of interference with 13 + 14 = 27 dB. vital wireless services in the wide bandwidths covered by A simplified block diagram of a UWB system is shown UWB radiation, spectral density limits allowed by the in Figure 5.2-31. A key to the generation of UWB pulses FCC and presumably to be permitted in the European is 