Patent ID: 7552154
Filing Date: 2009-06-23
Classification: G06F

Abstract:
1. A method for an apparatus to determine the probability density function type and the variance properties of the noise component N of a raw signal S of a machine or a system, said raw signal S being combined of a pure signal component P and said noise component N, the method comprising: a. defining a window within said raw signal; b. recording the raw signal S; c. numerically differentiating the raw signal S within the range of said window at least a number of times m to obtain an m order differentiated signal; d. finding a histogram that best fits the m order differentiated signal; e. finding a probability density function type that fits the distribution of the histogram; f. determining the variance of the histogram, said histogram variance being essentially the m order variance σ g. knowing the histogram distribution type, and the m order variance σ h. the apparatus outputting at least one of the zero order variance σ