Title: Seeing Impacting Clearly: Circular (Polar) Waveform Plots + Autocorrelation (Emerson Machinery Manager) In vibration analysis, we often talk about “impacting” — but the real value comes when we can prove whether an impact is repeatable (mechanically driven) or random (process/noise). Two time-domain tools in Emerson AMS Machinery Manager make this very visual: 1) Circular (polar) time waveform plot (0–360°) A circular plot is the time waveform “wrapped” into one machine cycle (0–360°). If an impact repeats at the same shaft angle, it shows up as a consistent spike/lobe at the same position on the circle. ✅ In my example (image attached), the “BEFORE” plot shows a spiky / star-like ring — classic impulsive behaviour. ✅ The “AFTER” plot becomes more uniform and circular, indicating reduced impacting and more stable running behaviour. 2) Why autocorrelation matters here Autocorrelation is a repeatability detector for the waveform: Strong autocorrelation peaks at the running period ...