Reflection function of a plane sound wave in a cylindrical tube

As dissipation and dispersion of plane waves in a cylindrical tube are proportional to the square root of frequency, the form of the impulse response can be obtained analytically. We analyse the reflection function at the input of the tube, i.e. the inverse Fourier transform of the reflection coefficient, especially the important distortions due to a numerical treatment and the property of stability through convolution. Using this property, the reflection function is determined for a sequence of tubes as well as for a connection of three tubes. An extension of the formulas to the case of rigid-walled closed cylindrical tube is given in Appendix A Etude de la fonction de reflexion a l'entree d'un tuyau et des importantes distorsions dues au traitement numerique ainsi que de la propriete de stabilite par convolution. Fonction de reflexion pour plusieurs tubes en serie et pour un branchement de 3 tubes