Method and apparatus for vibration sensing and analysis
A method and apparatus for sensing and measuring stress waves. The method comprises the steps of: a.) sensing motion, where the motion comprises a stress wave component and a vibration component; b.) separating the stress wave component from the vibration component with a high pass filter to create a signal proportional to the stress wave; c.) amplifying the signal to create an amplified signal; d.) processing the amplified signal with a sample and hold peak detector over a predetermined interval of time to determine peaks of the amplified signal over said predetermined period of time; e.) creating an output signal proportional to the determined peaks of the amplified signal; and, f.) repeating steps d.) and e.). The invention also includes an apparatus for implementing the method of the invention.
1. A method for sensing and measuring stress waves, comprising:
a.) sensing motion, where said motion comprises a stress wave component and a vibration component;
b.) separating said stress wave component from said vibration component with a high pass filter to create a signal proportional to said stress wave;
c.) amplifying said signal to create an amplified signal;
d.) processing said amplified signal with a sample and hold peak detector over a predetermined interval of time to determine peaks of said amplified signal over said predetermined period of time;
e.) creating an output signal proportional to said determined peaks of said amplified signal; and,
f.) repeating steps d.) and e.).
2. The method recited in claim 1 , further comprising the step of averaging said peaks of said amplified signal.
3. The method recited in claim 1 wherein said high pass filter is selectable about a plurality of frequencies.
4. The method recited in claim 2 wherein said high pass filter is selectable about 1 KHz and 5 KHz.
5. The method of claim 1 wherein said amplifying is done with a logarithmic amplifier.
6. The method of claim 1 wherein said sensing is done with an accelerometer.
7. The method of claim 1 wherein said sensing is done with a strain gauge.
8. An apparatus for sensing and measuring stress waves, comprising:
a.) means for sensing motion, where said motion comprises a stress wave component and a vibration component;
b.) means for separating said stress wave component from said vibration component to create a signal proportional to said stress wave;
c.) means for amplifying said signal to create an amplified signal;
d.) means for processing said amplified signal with a sample and hold peak detector over a predetermined interval of time to determine peaks of said amplified signal over said predetermined period of time;
e.) means for creating an output signal proportional to said determined peaks of said amplified signal; and,
f.) means for repeating steps d.) and e.).
9. The apparatus recited in claim 8 wherein said means for sensing is an accelerometer.
10. The apparatus recited in claim 8 wherein said means for sensing is a strain gauge.
11. The apparatus recited in claim 8 wherein said means for separating said stress wave component from said vibration component to create a signal proportional to said stress wave is a high pass filter.
12. The apparatus recited in claim 11 wherein said means for separating said stress wave from said vibration component to create a signal proportional to said stress wave comprises a selectable dual frequency high-pass filter, selectable to pass signals above at least two different frequencies.
13. The apparatus recited in claim 12 wherein said high-pass filter is selectable about 1 KHz or 5 KHz.