Optimized weights spectrum autocorrelation: A new and promising method for fault characteristic frequency identification for rotating Machine fault diagnosis

•Optimized weights spectrum autocorrelation (OWSAC) is newly proposed to identify fault characteristic frequencies.•OWSAC demodulates signals from the frequency domain.•OWSAC is autocorrelation of a purified spectrum in which interferential and noise spectral lines are automatically eliminated.•Two case studies demonstrate the superiority of the proposed OWSAC to five existing methods.