Cyclic time averaging for machine monitoring
A cyclic time averaging method is directed at processing time-domain vibration data of the machine to produce an averaged time waveform over a selected cyclic time period. It is not necessary to employ a triggering signal to obtain the averaged time waveform.
1. A system for analyzing vibration data, said system comprising:
an input port configured to receive a plurality of vibration amplitude samples taken at discrete sampling times, wherein said vibration amplitude samples are taken from a machine having a characteristic repeated cyclic phenomena recurring over a period M;
a first module configured to estimate vibration amplitudes at times between said discrete sampling times, wherein said first module comprises an interpolator; and
a second module configured to use said estimated vibration amplitudes in performing a cyclic average,
wherein adjacent discrete sampling times are separated by a time period of 1/F S , where F S is a sampling frequency, and wherein period M=(n+α)/F S , wherein n is an integer, and α is a number between 0 and 1.
2. A system for analyzing vibration data, said system comprising:
an input port configured to receive a plurality of vibration amplitude samples taken at discrete sampling times, wherein said vibration amplitude samples are taken from a machine having a characteristic repeated cyclic phenomena recurring over a period M;
a first module configured to estimate vibration amplitudes at times between said discrete sampling times, wherein said first module comprises an interpolator; and
a second module configured to use said estimated vibration amplitudes in performing a cyclic average,
wherein said second module comprises an averager configured to produce an average vibration amplitude by computing the average of a first sampled value at time p and the sampled or interpolated vibration amplitude value at one or more later times p+m(n+α), where m is an integer, n is an integer, and α is a number between 0 and 1.