show_2sided.m

Rotating shafts experience a an elliptical motion called whirl. It is important to decompose this mo

% demod_fb_demo
%
% use  two sensors at right angle to construct a bi-directional spectrogram
% representing  a whirling shaft
% 
% Ref. 
% I. Bucher and D.J. Ewins, "Multi-dimensional decomposition of time-varying vibration response signals in rotating machinery",
%                                   Mechanical Systems and Signal Processing, Vol. 11, No. 4, pp. 577-601, 1997
%
%  Postive frequencuencies --> whirl in a co-ratiting direction
%  Negative frequencies     -->  whiel in a counter-rotating direction
%
% acknowledgement:
%                   Many thanks to my friend Goetz von-Groll who did the
%                   actual measurement near 10 years ago ....
% 10-Sep-2003
% I. Bucher


 load gotz2
 
     Fs=1000;
     zmodfb([y(:,[2 1])],Fs)
     axis xy