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
 Pawula R.F. (1999). Improved performance of coded digital FM, IEEE Transactions on Communications, Vol. 47, No. 11, pp. 1701-1708. DOI: 10.1109/26.803505
 David T. (2003). PCM/FM performance enhancement using reed Solomon channel coding, IEEE Aerospace Conference Proceedings 2003, Big Sky, pp. 1337-1346.
 Geoghegon M. (2003). Experimental results for PCM/FM, Tier 1 SOQPSK and Tier 2 multi-h CPM with turbo-product codes, Proceedings of International Telemetry Conference 2003, Las Vegas, pp. 465-468.
 Wang L. (2004). Using LDPC codes to enhance the performance of FM-DCSK, the 47th IEEE International Midwest Symposium on Circuits and Systems 2004, pp. I-401-I-404.
 Rice S.O. (1963). Noise in FM receiver, Time Series Analysis, M. Rosenblatt, Ed. Wiley, New York, pp. 395-422.
 Kouwenhoven L. (1997). A new simple design model for FM demodulators using soft-limiters for click noise suppression, IEEE International Symposium on Circuits and Systems 1997, pp. 265-268. DOI: 10.1109/ISCAS.1997.608696
 Zhao Y.X. (1995). Gaussian mixture density modelling of non-Gaussian source for autoregressive process, IEEE Transactions on Signal processing, Vol. 43, No. 4, pp. 894-903.
 Verbout M. (1998). Parameter estimation for autoregressive Gaussian-mixture processes: the EMAX algorithm, IEEE Transactions on Signal processing, Vol. 46, No. 10, pp. 2744-2756. DOI: 10.1109/ICASSP.1997.604632
 Wang P.B. (2010). G-Filter's Gaussianization function for interference background, 2010 International Conference on Signal Acquisition and Processing, pp. 76-79.
 Pyndiah R.M. (1998). Near-optimum decoding of product codes: block turbo codes, IEEE Transactions on Communications, Vol. 46, No. 8, pp. 1003-1010. DOI: 10.1109/GLOCOM.1994.513494
 Low Density Parity Check Codes for Use in Near-Earth and Deep Space Applications (2007). CCSDS.