Mathematical Problems in Engineering
Volume 2010 (2010), Article ID 143582, 9 pages
Research Article

On the Integration Schemes of Retrieving Impulse Response Functions from Transfer Functions

1College of Science, China Agricultural University, P.B. 74, East Campus, Beijing 100083, China
2The First Affiliated Hospital of China People's Liberation, Army General Hospital, Beijing 100037, China

Received 7 February 2010; Accepted 28 December 2010

Academic Editor: Moran Wang

Copyright © 2010 Kui Fu Chen and Yan Feng Li. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The numerical inverse Laplace transformation (NILM) makes use of numerical integration. Generally, a high-order scheme of numerical integration renders high accuracy. However, surprisingly, this is not true for the NILM to the transfer function. Numerical examples show that the performance of higher-order schemes is no better than that of the trapezoidal scheme. In particular, the solutions from high-order scheme deviate from the exact one markedly over the rear portion of the period of interest. The underlying essence is examined. The deviation can be reduced by decreasing the frequency-sampling interval.