Table 1 The statistics of the vibration properties of 27 audible DVAV signals extracted by our software.
Mean | Mode | Median | Min | Max | Skew | Kurtosis | |
|---|---|---|---|---|---|---|---|
Frequency (Hz) | 18.21 | 16.11 | 17.89 | 13.1 | 22.75 | 0.065 | 2.67 |
Duration (s) | 1.01 | 0.92 | 0.99 | 0.49 | 1.68 | 0.46 | 2.54 |
Number of knocks | 17.92 | 17.92 | 18 | 8 | 27 | −0.12 | 2.27 |
Time between two knocks (s) | 0.0056 | 0.0054 | 0.05 | 0.044 | 0.065 | 0.84 | 4.2 |