r2
    The ordinary coherence functions between the inputs, 12 and between each input


                r2        2Y
and the output, ly and r2 are shown in Figure 3-14. Also, the multiple coherence function, r2.,, is shown in Figure 3-14.

    The results indicate a large content of the output spectrum is a part of the "noise" G,, that is not modeled. However, the multiple coherence function (and other ordinary coherence functions) is close to I at certain frequencies indicating that contribution at these frequencies are largely due to the stated inputs x, and X2, i.e. the z axis component of the vibration measured by the accelerometers near the fan and pump, respectively.