Synchronous Analysis


Set up an accelerometer and tachometer. If the tachometer pulse is taken from the belt, only the vibration related to the belt frequencies remains in the spectrum. You must have a tachometer that provides a once-per-revolution pulse. The shaft with the tachometer is the “reference” shaft.


Synchronous Analysis collects synchronous data on equipment when high nonsynchronous energy (background vibration) obscures the synchronous frequencies you want to see. You can also use it for drive belt analysis and when vibration from other equipment is excessive. Synchronous Analysis is useful for gear boxes that have multiple internal shafts turning at various speeds based on the gearing. This test helps to narrow the vibration to look at a specific speed of the shaft.

The analyzer averages vibration from other shafts turning at other speeds and vibration from the reference shaft that is not harmonically related to the turning speed. The resulting data is phase locked to the tachometer pulse. Only the turning speed vibration and its integer multiples are left in the spectrum. The analyzer removes vibration not related to the reference tachometer pulse.


  1. Create a job or open Analyze from a route measurement point.
  2. From the Analyze main menu, press F7 More Experts > F9 Synchronous Analysis.
  3. Press Start or Enter to collect the data.
  4. Press Enter to view the data.
    One or more plots display after the data is collected.
  5. Press F9 Store Data to save the data to a route or a job, or press F8 Start to redo the measurement.