Time-Synchronous Signal Averaging

Use time-synchronous signal averaging (TSA) when you are working with data from rotating machinery.

With rotating machinery, a single rotation period encapsulates the full gamut of machinery component interaction. Averaging over uniform rotation angles or complete rotations, rather than averaging over more arbitrary time segments, rejects any noise, disturbance, or periodic signal content that is not coherent with the rotation. This rotation-based averaging is called time-synchronous averaging, or TSA.

  • Signal — Signal to be averaged

  • Tacho Information — Rotation rate, specified as one of the following:

    • Constant rotation speed (RPM) — Use constant RPM when your rotation rate is fixed both in time and across all ensemble members.

    • Tacho signal — Use a tacho signal when you have a tachometer that transmits pulses at specific angular points in the rotation. Your tacho signal must have the same length as your data signal.

    • Compute nominal speed (RPM) — Compute the nominal rotation speed for each individual machine when processing the tacho signal. Select this option if the rotation speeds of your machines vary across the ensemble and you plan on filtering the TSA signal (see Filter Time-Synchronous Averaged Signals). The app stores the computed rotation speeds in a condition variable with the suffix rpm.

      For an example of performing TSA processing with varying nominal wheel speeds, see Isolate a Shaft Fault Using Diagnostic Feature Designer

  • Interpolation method — Select the interpolation to use when computing the TSA signal. For information on the interpolation methods and the algorithms for using them, see tsa.

  • Pulses per rotation — Number of tachometer pulses in each rotation. Set this parameter only when using a tacho signal.

  • Number of rotations — Typically, a TSA signal averages over a single rotation. Increase the number of rotations when you want to improve frequency resolution for follow-on filtering of the TSA signal.

The software stores the results of the computation in a new variable. The new variable name includes the source signal name with the suffix tsa.

Additional Information

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