Impact of the non-uniform angular sampling on mechanical signals

Angular sampling is a useful tool to study cyclic rotating machine vibrations. It can be implemented by using computer order tracking, directly, or by extracting position information from an acceleration signal. Instantaneous speed can also be angularly sampled using a counter technique. Angular sampling is sensitive to hardware imperfections (optical encoder precision, electrical perturbation, etc.). Angular sampled signal quantification step or sampling frequency determination is not identical to time domain. Angular sampling is also not adapted to study time domain signals like impulse response. Some of these imperfections can be viewed as non-uniform sampling.