Chapter 5: Digital CT Scan of Sound — From Subjective Ear Listening to Kurtosis Impulse Detection & FFT Spectral Analysis
An intuitive, practical engineering guide to gearbox NVH digital signal diagnostics: why decibel meters miss single-tooth dings, how Kurtosis 4th-power amplification catches burrs and cracks, how FFT separates mixed gearbox sounds, 3 simple arithmetic rules to locate faulty gears, 50ms impulse envelope tracking, and tooth profile tip relief / lead crowning.
Gearbox NVH & Mechanical Noise Diagnostic Handbook
A practical, easy-to-understand engineering handbook on gearbox noise and vibration testing. Covering sound pressure and decibels (dB/dBA), why human ear listening is unreliable, the difference between gear whine and rattle, sensor setups, and transitioning to digital FFT diagnostics.
Read More →Chapter 2.1: Why Does a Gearbox Ring Multiple Times in a Single Turn? — Shaft Frequencies, Mesh Harmonics, Sidebands & Order Tracking
An intuitive engineering guide to rotating machinery acoustics: why a single shaft revolution generates hundreds of acoustic events, shaft frequencies (fr), gear mesh frequencies (fm = Z*fr) and harmonics, mechanical amplitude (AM) and frequency (FM) sideband modulation, hunting tooth prevention, and how angular resampling Order Tracking overcomes spectral smearing under speed sweeps.