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The BER performance of the coded digital PCM/FM telemetry system is dependent on the accuracy of the input likelihood metrics, which are greatly influenced by the click noise. This paper presents a Gaussianization approach to lessen the influence of the click noise. The outputs of the limiter/discriminator are first modeled by a Gaussian mixture model, whose parameters are estimated by the expectation maximization algorithm, and then the amplitudes are adjusted by a proposed Gaussianization filter so that they become more accurate through likelihood metrics. When (64, 57)2 TPC is applied, simulation results show the coding gain is 0.8dB at 10-4 BER level.
PCM/FM, Limiter/Discriminator, Gaussianization, Turbo Product Codes, LDPC
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