the synchronous (time domain) average revisited

synchronous averaging is one of the most powerful techniques for the extraction of periodic signals from a composite signal. it is based on averaging periodic sections, necessitating an a-priori knowledge of the period sought. it is one of the most effective signal processing tools applied to rotating machinery, and has been known and used for decades.it will be shown that synchronous average is actually just one of the many possible "synchronous filters" which could be used to extract the above periodic components performance. a novel signal analysis, geared to periodic signals will be introduced, with the potential of extracting more complex phenomena typical of some rotating machinery. examples given are based on periodic oscillating transients, with various additive interferences. the possibility of additional signal processing approaches is also discussed.