Electronic signal enhancement and separation for machinery diagnostics

Abstract

A signal enhancement system for separating a composite diagnostic signal detected in a rotating machine into component signals representative of the contributions to the composite signal of a number of independent sources. The signal enhancement system includes at least one signal subtraction loop having a transducer which produces a reference signal based on the rotational speed of a rotating shaft in the machine and an adaptive filter connected to the transducer. The adaptive filter processes the reference signal to produce a component signal which closely approximates the contribution of the rotating shaft to the composite signal. A summer is also included which subtracts the component signal from the composite diagnostic signal to produce a second component signal. Both the first and second component signals are provided as outputs of the system. The system can be implemented with a plurality of signal subtraction loops wherein, the summer of the first loop subtracts the component signal of the first loop's adaptive filter from the composite diagnostic signal to produce an output signal. Then, the summer of each successive loop subtracts the component signal of that loop's adaptive filter from the output signal of the prior loop. The last output signal and each component signal are the system output.