Spectral Properties of Ultra Wideband Signals with General Time-Hopping Codes

Spectra of ultra wideband (UWB) signals are restricted to frequency masks defined by regulation authorities like the Federal Communications Commission (FCC) in the United States or the Regulierungsbehorde fur Telekommunikation und Post (RegTP) in Germany. To make optimum use of these frequency masks, technologies that smooth the peaks in the signals' power spectral density (PSD) should be implemented. This contribution investigates the influences of various modulation schemes as well as different time hopping codes with general probability density functions on the PSDs of impulse radio UWB signals