Method and device for characterising a signal

1. A method of characterizing a signal produced by acquisition means connected to equipment, the method comprising: A) acquiring a signal using the acquisition means; B) determining a vibration rating of at least a portion of the signal acquired in step A, the vibration rating being a function solely of rapid fluctuations of the signal, excluding information representing slow variations of the signal, the vibration rating being equal to a normalized value of a vibration content over a time window, the vibration content being extracted by from the signal acquired in step A; C) determining a level of variation of at least a portion of the signal acquired in step A, the level of variation being representative of slow variations of the signal, the level of variation being equal to a rate of increase of a quasi-static variation of the signal over the time window during one time step; and D) determining information characterizing the signal by applying at least two different functions that combine at least said vibration rating and said level of variation, wherein the quasi-static variation of the signal is equal to a mean value of the signal acquired in step A over the time window.

2. The method of characterizing a signal according to claim 1 , wherein values of at least one indicator are calculated, from at least one of the vibration rating and the level of variation; and information characterizing the signal is determined in step D from said at least one indicator.

3. The method of characterizing a signal of claim 2 , wherein the values of the at least one indicator are calculated using a predetermined table.

4. The method of characterizing a signal according to claim 1 , wherein the signal comprises calculated information.

5. The method of characterizing a signal according to claim 1 , wherein the signal comprises information obtained using at least one sensor.

6. The method of characterizing a signal according to claim 1 , wherein the vibration rating and the level of variation are determined for a common portion of the signal.

7. The method of characterizing a signal according to claim 1 , wherein, in step D, the functions combine the vibration rating and the level of variation by using at least one of a threshold, an arithmetic operator, a Boolean operator, and a fuzzy logic operator.

8. The method of detecting failures in which a failure is detected on the basis of at least one piece of information obtained by the method according to claim 1 .

9. A non-transitory computer readable data medium storing a computer program including instructions for executing steps of a method according to claim 1 .

10. The method of characterizing a signal according to claim 1 , wherein the vibration content is a signal of zero mean corresponding to medium and high frequencies of the signal acquired in step A.

11. The method of characterizing a signal according to claim 1 , wherein said information comprises a first piece of information designating a state of the signal and a second piece of information designating a confidence index to be given to said state of the signal.

12. A device for characterizing a signal, the device comprising:

a data acquisition card which acquires a signal and configured to be connected to equipment; and

circuitry configured to

determine a vibration rating, suitable for determining a vibration rating of at least a portion of the acquired signal, the vibration rating being a function solely of rapid fluctuations of the signal, excluding information representing slow variations of the signal, the vibration rating being equal to a normalized value of a vibration content over a time window, the vibration content being extracted from the signal;

determine a level of variation suitable for determining a level of variation of at least a portion of the acquired signal, the level of variation being representative of slow variations of the signal, the level of variation being equal to a rate of increase of a quasi-static variation of the signal over the time window during one time step; and

determine information characterizing the acquired signal and suitable for determining information characterizing said signal by applying at least two different functions combining at least said vibration rating and said level of variation,

wherein the quasi-static variation of the signal is equal to a mean value of the signal acquired by the data acquisition card over the time window.