It is pointed out that Theorems 2.2 and 3.1 developed by Al-Humadi and Rabson in [Int. J. Control 46 (1987), 1355-1366], concerning the characterization and calculation of the finite transmission zeros of linear time-invariant descriptor systems, are not correct. Based on Kronecker�s canonical form of a singular matrix pencil, a new and simple algorithm is also presented for calculating finite transmission zeros of linear time-invariant descriptor systems.

finite transmission zeros, linear time-invariant descriptor systems, system zeros, matrix pencil, input decoupling zeros, output decoupling zeros, Kronecker�s canonical form.