Signal processing system for sensing a periodic signal in the presence of another interfering signal
AssigneeActive Noise and Vibration Technologies, Inc.
InventorsColin F. Ross, Graham P. Eatwell
Life of this patent
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Abstract
A signal processing system, especially for use in vibration control, wherein noise-free signals inductive of the timing of a primary source and of the timing of at least one interfering secondary source of periodic vibrations are provided as inputs, together with a vibration input signal derived from a sensor sampling the vibrations, and wherein the signals are processed to produce an output representative of interference free vibration of the primary source.
Claims14
A method of monitoring a first substantially periodic signal component of a compound signal which includes a second substantially periodic signal component, wherein the first and second signal components have separate sources, comprising the steps of:
- (a) sensing the first and second signal components respectively;
- (b) determining a beat period as a function of the sensed first and second signal components;
- (c) sampling the compound signal in synchronism with the first signal component;
- and
- (d) averaging the compound signal samples over a period determined by said beat period to produce a contribution signal as a function of a contribution made to the compound signal by the first signal.
A method of at least partially cancelling a compound signal including a first substantially periodic signal component and a second substantially periodic signal component, wherein the first and second signal components have separate sources, including the steps of:
- (a) Monitoring the first signal component by performing the steps:
- (i) sensing the first and second signal components respectively;
- (ii) determining a beat period as a function of the sensed first and second signal components;
- (iii) sampling the compound signal in synchronism with the first signal component;
- and
- (iv) averaging the compound signal samples over a period determined by said beat period to produce a contribution signal as a function of a contribution made to the compound signal by the first signal;
- and
- (b) generating a cancelling signal to cancel the first signal component of the compound signal in dependence on said contribution signal.
An apparatus for monitoring a first substantially periodic signal component of a compound signal which includes a second substantially periodic signal, wherein the first and second signal components have separate sources, comprising:
- first sensor means for sensing the first signal component before it becomes combined in the compound signal, said first sensor means having an output;
- second sensor means for sensing the second signal component before it becomes combined in the compound signal, said second sensor means having an output;
- third sensor means for sensing the compound signal, said third sensor means having an output;
- means for producing a controlling signal as a function of the output from the first and second sensor means;
- sampling means arranged to sample the output from the third sensor means in synchronism with the output of the first sampling means;
- and
- accumulator means for accumulating the compound signal samples over a period determined by the controlling signal to produce a contribution signal as a function of the contribution made to the compound signal made by the first signal component.
Dependencies are inferred from the claim text.