compute_spectrogram_stft
Computes time-frequency spectrogram from stored signal to detect transient faults and speed changes in vibration data.
Instructions
Compute STFT spectrogram for a stored signal.
Returns time-frequency summary (no full 2D array). Use for detecting
time-varying frequency content (transient faults, speed changes).
Args:
signal_id: ID of the stored signal.
nperseg: Samples per STFT segment (default 256).
noverlap: Overlap between segments (default 128).
window: Window function (default 'hann').
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| signal_id | Yes | ||
| nperseg | No | ||
| noverlap | No | ||
| window | No | hann |
Output Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| signal_id | Yes | Signal identifier used | |
| num_samples | Yes | Number of samples analyzed | |
| sampling_rate | Yes | Sampling rate (Hz) | |
| nperseg | Yes | Samples per segment | |
| noverlap | Yes | Overlap between segments | |
| window | Yes | Window function used | |
| num_time_bins | Yes | Number of time bins | |
| num_freq_bins | Yes | Number of frequency bins | |
| freq_range_hz | Yes | [min_freq, max_freq] | |
| time_range_s | Yes | [start_time, end_time] | |
| max_power_freq_hz | Yes | Frequency with maximum power | |
| max_power_time_s | Yes | Time of maximum power | |
| energy_per_band | Yes | Energy in predefined frequency bands |