Envelope Analysis

The envelope spectrum is one of the most powerful tools in MultiViz for detecting bearing and impact-related faults early — often well before the broadband signal reacts. This article covers the envelope-specific tools: filters, the two envelope KPIs, and automatic jump detection.

Envelope filters

Preset and customizable envelope filters are available for signal analysis. Applying a filter isolates a specific frequency band, improving the accuracy of fault detection. The envelope spectrum keeps its own dedicated filter, independent of the frequency filter on waveform views.

The envelope KPIs: Peak Score and RMS

Two Key Performance Indicators are tracked for the envelope signal:

• Envelope Peak Score — a weighted sum of prominent peaks, designed to detect impacts and help assess their severity.
• Envelope RMS — a clear measurement of the overall energy in the envelope signal.

Automatic jump detection on the envelope

The jump-on-peak-score algorithm runs on the envelope peak score, just as it does on RMS. This catches developing failures earlier in their lifecycle — especially bearing faults, where the envelope picks up the first signs well before the broadband signal reacts.