Optimal predistortion of Gaussian inputs for clipping channels |
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Authors: | Keang-Po Ho Kahn J.M. |
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Affiliation: | Bellcore, Red Bank, NJ; |
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Abstract: | For a clipped channel with a Gaussian input, a predistortion/restoration technique to reduce clipping-induced nonlinear distortion is proposed and analyzed. The input signal is processed by a nonlinear predistorter circuit, reducing the probability of clipping. The receiver output signal passes through a restorer having an inverse transfer characteristic, which yields the original signal. For both one-sided and two-sided limiter channels, the optimal predistortion curves are determined analytically. A limiter channel with Gaussian input may be used to model clipping-induced nonlinear distortion in optical-fiber common antenna television (CATV) distribution systems using multiple intensity-modulated subcarriers. When applied to an amplitude-modulated vestigial-sideband (AM-VSB) CATV system, the optimal predistortion curves yield sensitivity improvements of 5.3 and 4.4 dB for oneand two-sided limiter channels, respectively |
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