Impulse Response of a Waveguide Subject to Mode Conversion-Reconversion

The paper presents a simple derivation of the impulse response of an overmoded circular waveguide carrying an H01 mode. It is assumed that rate of coupling between the H01 mode and the parasitic modes is small otherwise the coupling can be systematic (e.g. periodic) or random with a given power density spectrum (PDS). In the latter case the method gives an expression for the statistically expected impulse response. The results can be used subsequently, through the medium of convolution, to predict distortion of, for example, digital signals.