Title :
Nonlinear models of TWT revisited for OFDM systems
Author :
Barbieri, A. ; Cariolaro, G. ; Vangelista, L.
Author_Institution :
Dept. of Electr. Eng., Padova Univ., Italy
Abstract :
Recently, OFDM systems have received wide interest, particularly in the field of terrestrial broadcasting of all digital television in the UHF/VHF bands. The use of TWT (Traveling Wave Tubes) is considered for the final amplification of the OFDM signal. The OFDM modulated signal is very close to a Gaussian random process. In this paper we revisit the most popular TWT models and recognize that they belong to a peculiar class of non-linearities, S×FSM, in which the output is the product of the incoming complex signal and a function of its modulus. For S×FSM nonlinearities, driven by a Gaussian input, output statistics can be evaluated in closed forms. We apply this analysis to the TWT non-linearity, deriving the power spectral density of the output signal as well as the probability density function, when the input is an OFDM signal
Keywords :
Gaussian distribution; Gaussian processes; frequency division multiplexing; spectral analysis; travelling wave tubes; Gaussian input; Gaussian random process; OFDM modulated signal; OFDM systems; S×FSM nonlinearities; TWT; UHF band; VHF band; all digital television; closed form output statistics; nonlinear models; orthogonal frequency division multiplexing; power spectral density; probability density function; spectral analysis; terrestrial broadcasting; traveling wave tubes; Digital TV; Gaussian processes; Linearity; OFDM modulation; Probability density function; Random processes; Signal analysis; Signal processing; Solid modeling; Statistical analysis; Statistics; TV broadcasting;
Conference_Titel :
Circuits and Systems, 1995., Proceedings., Proceedings of the 38th Midwest Symposium on
Print_ISBN :
0-7803-2972-4
DOI :
10.1109/MWSCAS.1995.504491
