Setting the proper LOR is essential to be able to separate closely spaced defect frequencies.  An example would be a pump with 5 vanes that could generate a “Vane Pass” frequency equal to the number of vanes,  or 5 times rotational speed; if the impeller end of the pump had an SKF 7301BEP bearing, it could have an inner race defect frequency of 4.99 times running speed.  This combination would require a relatively high resolution or LOR in order to have enough detail to separate the defect frequencies of each defect.