Particle detection and analysis
First Claim
1. A method of detecting and analysing moving particles using a transducer which generates an electrical signal in response to a particle impact, having an amplitude which is related to the force of particle impact, the method comprising the steps of:
- a. monitoring the instantaneous values of the transducer output signal;
b. detecting when the amplitude of the transducer output signal exceeds a given threshold and noting any local maximum values whilst the transducer output signal exceeds the said threshold;
c. determining which of a plurality of local maximum values has the overall maximum amplitude so as to discriminate between electrical noise spikes and an amplitude excursion caused by a particle impact; and
d. generating a final output signal whose amplitude corresponds to the detected local overall maximum value and whose timing bears a fixed relationship to the time at which the local overall maximum value occured to thereby generate a signal which is indicative of the momentum and position in time of a particle impact.
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Abstract
The invention provides a method of, and apparatus for detecting and analyzing moving particles using an impact responsive transducer which generates a detection signal having an amplitude related to force of particle impact. The transducer output signal is monitored and when it exceeds a given threshold, any local maximum values are noted. Those values are compared to determine which has the overall maximum amplitude. A final signal is then generated in order to provide a representation of the maximum value, and hence the momentum and time occurrence of a particle impact.
23 Citations
14 Claims
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1. A method of detecting and analysing moving particles using a transducer which generates an electrical signal in response to a particle impact, having an amplitude which is related to the force of particle impact, the method comprising the steps of:
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a. monitoring the instantaneous values of the transducer output signal; b. detecting when the amplitude of the transducer output signal exceeds a given threshold and noting any local maximum values whilst the transducer output signal exceeds the said threshold; c. determining which of a plurality of local maximum values has the overall maximum amplitude so as to discriminate between electrical noise spikes and an amplitude excursion caused by a particle impact; and d. generating a final output signal whose amplitude corresponds to the detected local overall maximum value and whose timing bears a fixed relationship to the time at which the local overall maximum value occured to thereby generate a signal which is indicative of the momentum and position in time of a particle impact. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for detecting and analysing particle impacts, comprising a sensor which generates an electrical amplitude excursion in response to a particle impact, the maximum amplitude of which is related to the momentum of the particle causing the impact;
- a peak detector for detecting peaks in the sensor output;
signal processing means for measuring the amplitude and time of occurrence of each peak;
comparator means for determining which of a series of peak values has the local overall maximum value; and
output means for processing as a final output signal, a signal having a value corresponding to the locally detected overall maximum and whose timing corresponds to the time of the detected impact. - View Dependent Claims (12, 13, 14)
- a peak detector for detecting peaks in the sensor output;
Specification