Archives of Acoustics, 31, 2, pp. 167-177, 2006

Demodulation of non-stationary machine vibration using cycle-time scale

P. KRZYWORZEKA
AGH University of Science and Technology Department of Mechanics and Vibroacoustics

W. CIOCH
AGH University of Science and Technology Department of Mechanics and Vibroacoustics

Inner time-scale affects the operation of angle demodulator. Can linear approximation of monotonic variations in carrier-cycle improve the recovery of unknown low-energy signal modulating observable vibration processes? Authors make an attempt to answer using phase-locked loop PLL as demodulator. Simulations conducted for complex phase model indicate potentially vast possibilities of recognizing and selection of information component. Appropriate selection of approximation time-range enables to achieve acceptable RMS value loads and harmonics of rotational speed of outgoing estimates.
Keywords: diagnostics, modulation, synchronism
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