{"references": ["R. F. Lyon, ''A computational model of filtering, detection, and compression in cochlea,'' in Proc. IEEE Intl. Conf. On Acoust.Speech,Signal Processing, pp. 1282-1285, Paris, France, May, 1982.", "R.D. Patterson, and J. Holdsworth, ''A functional model of neural activity patterns and auditory images,'' William A. Ainsworth (ed.), vol.3, Advances in Speech, Hearing and Language Processing, JAI Press,London, 1996.", "M. Slaney, ''An efficient implementation of the Patterson-Holdsworth auditory filterbank,'' Apple Computer Tech. Rep. 35, Apple Computer,1988.", "R. Meddis, M. J. Hewitt, and T. M. Shackleton, ''Implementation details of a computation model of the inner-hair cell/auditory -nerve synapse,''J. Acoust. Soc. Am., vol. 87, no. 4, pp. 1813-1816, Oct. 1990.", "S. B. Davis, and P. Mermelstein, ''Comparison of parametric representations for monosyllabic word recognition in continuous spoken sentences,'' IEEE Trans.Accoust. Speech and Signal Processing,vol. 28,no. 4, pp. 357-366, 1980.", "R. F. Lyon, and C. Mead, ''An analog electronic cochlea,'' IEEE Trans.Accoust. Speech and Signal Processing,vol. 36, no. 7, pp. 1119-1134,July 1988.", "E. Givelberg, and J. Brunn, ''A comprehensive three-dimensional model of the cochlea,'' J. Comp. Physics, vol. 191, no. 2, pp. 377-391, Nov.2003.", "R. M\u251c\u255dller, ''A computational theory for the classification of natural biosonar targets based on a spike code,'' Network: Comput. Neural Syst., vol. 14, pp. 595-612, May 2003.", "J. M. Kates, ''A time-domain digital cochlear model,'' IEEE Trans.Signal Proc., vol. 39, no. 12, pp. 2573-2591, Dec. 1991.[10] M. S. Srivastava, and E.M. Carter, Applied Multivariate Statistics,North Holland Amsterdam, 1983."]}

An improved processing description to be employed in biosonar signal processing in a cochlea model is proposed and examined. It is compared to conventional models using a modified discrimination analysis and both are tested. Their performances are evaluated with echo data captured from natural targets (trees).Results indicate that the phase characteristics of low-pass filters employed in the echo processing have a significant effect on class separability for this data.