analyze_statistics
Calculate key statistical parameters like RMS, crest factor, kurtosis, and peak-to-peak from a loaded signal to screen for machinery faults in vibration diagnostics.
Instructions
Calculate statistical parameters of a stored signal for diagnostics.
Statistical parameters are key indicators for diagnostics:
- RMS: Effective value, correlated to signal energy
- Crest Factor: Indicates presence of impulses (high = possible faults)
- Kurtosis: Measures impulsiveness (excess kurtosis; >0 = non-Gaussian, >3 = strong impulses)
- Peak-to-Peak: Signal range
Requires the signal loaded via load_signal() first. Statistical
parameters are screening indicators, not definitive diagnostics —
combine with frequency-domain evidence.
**Signal units:** all values are in the signal's native unit. The unit
is reported only when DECLARED — load_signal(signal_unit=...) or the
companion _metadata.json — and never guessed from signal amplitude.
ISO 20816-3 severity tools refuse to produce a verdict until the unit
is declared.
Args:
signal_id: ID of the stored signal (from load_signal).
Returns:
StatisticalResult with all statistical parameters
Raises:
ValueError: If the signal_id is not loaded.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| signal_id | Yes |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| rms | Yes | Root Mean Square (effective value) | |
| mean | Yes | Mean value | |
| peak | Yes | Peak value | |
| std_dev | Yes | Standard deviation | |
| kurtosis | Yes | Kurtosis (measure of impulsiveness) | |
| skewness | Yes | Skewness (asymmetry) | |
| unit_note | Yes | Unit declaration status and how to declare the unit for ISO severity assessment | |
| signal_unit | No | Declared signal unit ('g', 'm/s2', 'mm/s', 'm/s') from companion metadata — never guessed from amplitude. None when not declared. | |
| crest_factor | Yes | Crest Factor (Peak/RMS) | |
| peak_to_peak | Yes | Peak-to-peak value |