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
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
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
For more information on:
TSA signals — See
Tachometer signals — See
Rotating machinery features — See Condition Indicators for Gear Condition Monitoring.