Starting with a dashpot with coefficient , we have

and reflectance

This time, choosing equal to the element value gives

Conformally mapping the zero function yields the zero function so that

as well. Thus, the WDF of a dashpot is a ``wave sink,'' as diagrammed in Fig.F.4.

In the context of waveguide theory, a zero reflectance corresponds to
a *matched impedance,* *i.e.*, the terminating transmission-line
impedance equals the characteristic impedance of the line.

The difference equation for the wave digital dashpot is simply . While this may appear overly degenerate at first, remember that the interface to the element is a port at impedance . Thus, in this particular case only, the infinitesimal waveguide interface is the element itself.

[How to cite this work] [Order a printed hardcopy] [Comment on this page via email]

Copyright ©

Center for Computer Research in Music and Acoustics (CCRMA), Stanford University