WT4 Millimeter Waveguide System: Spectrum Estimation Techniques for Characterization and Development of WT4 Waveguide - II

The use of the spectral density function for the characterization of mode conversion effects in millimeter waveguide problems has been in general use since the pioneering paper of Rowe and Warters2 and has subsequently appeared in several other forms (Morrison and McKenna,3 Pusey4). In this paper the emphasis will not be on mode conversion problems per se but rather on the more fundamental problem of obtaining an accurate estimate of the spectrum for the geometric distortion causing the mode conversion. In Part I a technique for the estimation of the power spectral density function was described1 which differs from conventional estimation procedures in several respects. In particular the technique is both robust--that is, it is resistant to a moderate amount of erroneous or outlying data--and has the ability to estimate spectra which have very large dynamic ranges. While Part I was primarily theoretical, Part II is devoted primarily to examples of this technique as applied to the analysis 1983