Patent ID: 8810396
Filing Date: 2014-08-19
Classification: G01H,G01M

Abstract:
1. An apparatus for analysing a condition of a machine having a first part which is rotationally movable at a speed of rotation in relation to a second machine part, said apparatus including: a sensor for monitoring said movable part so as to generate at least one analogue measurement signal including at least one vibration signal component dependent on a vibration movement of said rotationally movable part; wherein said vibration signal component has a repetition frequency which depends on the speed of rotation of said first part; said measurement signal including noise as well as said vibration signal component so that said measurement signal has a first signal-to-noise ratio value in respect of said vibration signal component; an A/D-converter for generating a digital measurement data sequence in response to said measurement signal; said digital measurement data sequence having a first sample rate; a digital filter for generating a filtered measurement data signal in dependence on the digital measurement data sequence; a digital enveloper for producing an enveloped signal in response to the filtered measurement data signal; a decimator adapted to generate a decimated digital signal having a reduced sampling frequency dependent on said digitally enveloped signal; an enhancer having an input for receiving said decimated digital signal; said enhancer being adapted to produce an output signal sequence having a repetitive signal component corresponding to said at least one vibration signal component so that said output signal sequence has a second signal-to-noise ratio value in respect of said repetitive signal component; said second signal-to-noise ratio value being higher than said first signal-to-noise ratio value; and said enhancer being adapted to perform a correlation so as to produce said output signal sequence so that repetitive signal amplitude components are amplified in relation to stochastic signal components; wherein an evaluator for indicating a machine condition dependent on said vibration movement of said rotationally movable part in response to said output signal sequence.