系統識別在近年來愈來愈受到重視,有許多的專家學者提出各種不同的識別公式,本文即是針對F.E.Udwadia於1978年提出的識別公式加以探討。在本文中有探討拉普拉斯轉換在數值計算上解析解與數值解之間的誤差,並運用傅立葉SINE級數解決拉普拉斯轉換在参數趨近無窮大的數值計算問題,最後在本文中提出了一個新的識別公式。 In recent years, system identification has been attracted more and more attention. Scholars proposed many kinds of identification formulae. The goal of this study is to investigate the formulae which are proposed by F.E.Udwadia in 1978. In this study confer the errors between exact solution and numerical solution in numerical computation of Laplace transformation and by use of Fourier sine series to solve the numerical problems while parameter of Laplace transformation approach infinity. Finally, in this paper, it is proposed a new identification formula.