Energy peak/time averaging seismic intrusion detector

Claim 2

A seismic intrusion detector for discriminating between periodic energy bursts and other seismic signals, said detector comprising: 1. input means for receiving seismic energy signals; 2. means coupled to said input means for detecting energy peaks from energy bursts in said seismic signals; 3. means coupled to the detecting means and responsive to the detected energy peaks for producing a first signal, said first signal having an amplitude proportional to the average rate of the detected peaks and said first signal having a time-varying amplitude component indicative of the period of each of said peaks; 4. means for producing a second signal indicative of the average amplitude of said first signal; 5. means for comparing said first and second signals to provide a third signal when the time-varying component of said first signal is within a predetermined range about said second signal; and 6. means coupled to Said comparing means and responsive to said third signal for providing an output signal when the integrated value of said third signal exceeds a predetermined level.

Claim 3

A seismic intrusion detector for discriminating between periodic energy bursts and other seismic signals, said detector comprising:

Claim 4

A seismic intrusion detector for discriminating between periodic energy bursts and other seismic signals, said detector comprising:

Claim 5

input means for receiving seismic energy signals;

Claim 6

input means for receiving seismic energy signals;

Claim 7

means coupled to said input means for detecting energy peaks from energy bursts in said seismic signals;

Claim 8

means coupled to said input means for detecting energy peaks from energy bursts in said seismic signals;

Claim 9

The intrusion detector according to claim 1, wherein said detecting means includes analog means for producing an analog signal whose amplitude varies in accordance with the amplitude of said detected energy peaks and wherein said analog means includes means coupled to the means responsive to said third signal, for weighting the integration of said third signal in response to the amplitude of said energy peaks to cause the integrated value of said third signal to vary in accordance with the amplitude of said energy peaks.

Claim 10

The intrusion detector according to claim 2, wherein said analog means includes means for integrating said analog signal so that the integrated value of said third signal varies in accordance with the average amplitude of said energy peaks.

Claim 11

means coupled to the detecting means and responsive to the detected energy peaks for producing a first signal, said first signal having an amplitude proportional to the average rate of the detected peaks and said first signal having a time-varying amplitude component indicative of the period of each of said peaks;

Claim 12

means coupled to the detecting means and responsive to the detected energy peaks for producing a first signal, said first signal having an amplitude proportional to the average rate of the detected peaks and said first signal having a time-varying amplitude component indicative of the period of each of said peaks;

Claim 13

means for producing a second signal indicative of the average amplitude of said first signal;

Claim 14

means for producing a second signal indicative of the average amplitude of said first signal;

Claim 15

The intrusion detector according to claim 1, wherein: said means for producing a first signal comprises an operational amplifier having an input coupled to said detecting means and an output coupled to said comparing means, and wherein the output of said amplifier is coupled to its input, thereby to form an operational amplifier integrator; and said means for producing a second signal comprises an integrator network having an input coupled to the output of said amplifier and an output coupled to said comparing means.

Claim 16

means for comparing said first and second signals to provide a third signal when the time-varying component of said first signal is within a predetermined range about said second signal; and

Claim 17

means for comparing said first and second signals to provide a third signal when the time-varying component of said first signal is within a predetermined range about said second signal; and

Claim 18

The detector according to claim 4, wherein said comparing means includes first and second comparators each comparator having a first input coupled to the output of said integrator network and a second input coupled to the output of said amplifier, and each comparator having an output coupled to the means responsive to said third signal.

Claim 19

The detector according to claim 5, wherein said comparing means further includes a third comparator having a first input coupled to a threshold potential and a second input coupled to said integrator network, said third comparator including means for inhibiting said third signal until the average amplitude of said first signal exceeds said threshold potential.

Claim 20

means coupled to Said comparing means and responsive to said third signal for providing an output signal when the integrated value of said third signal exceeds a predetermined level.

Claim 21

means coupled to Said comparing means and responsive to said third signal for providing an output signal when the integrated value of said third signal exceeds a predetermined level.

Claim 22

The intrusion detector according to claim 1, wherein said detecting means comprises: rectifier means for rectifying said seismic energy signals said rectifier means having an input coupled to said input means and said rectifier means having an output; first integrator means having an input coupled to said output of said rectifier, said first integrator means being responsive to the instantaneous energy of said rectified seismic signals; second integrator means having an input coupled to the output of said rectifier, said second integrator means being responsive to the average energy of said rectified seismic signals; and divider means having an input coupled to said first and second integrator means and an output for providing an energy ratio signal indicative of the ratio of said instantaneous energy to said average energy, wherein a burst of seismic energy in said seismic signals results in an energy peak signal at said output of said divider means.

Claim 23

The intrusion detector according to claim 7, wherein said detecting means further includes threshold means coupled between said divider means and the first signal producing means, for detecting only those energy peaks which exceed a given threshold level.

Claim 24

The intrusion detector according to claim 8, wherein said detecting means includes a digital peak detector for generating a peak-pulse in response to each detected energy peak, wherein the width of each peak-pulse is related to the time duration during which the corresponding energy peak exceeds said given threshold level.

Claim 25

The intrusion detector according to claim 9, wherein said first signal producing means includes peak-pulse shaping means for limiting the maximum pulse width of the peak-pulses, so that each width-limited peak-pulse is equal to or less than a given fiXed width; and wherein said first signal producing means includes integrator means responsive to each width-limited peak-pulse wherein said integrator means charges during the time duration of each width-limited peak-pulse and wherein said integrator means discharges during the time duration between successively occurring peak-pulses.

Claim 26

A seismic intrusion detector comprising, in combination: a. input means for receiving seismic energy signals; b. means coupled to said input means for amplifying and filtering said seismic signals, to provide an amplified version of said seismic energy signals within a predetermined bandwidth; c. rectifier means coupled to said amplifying and filtering means for rectifying the amplified signals; d. first and second integrator means, each coupled to said rectifier means for respectively providing signals representative of the instantaneous and average value of said seismic energy signals; e. divider means coupled to said first and second integrator means for providing an energy ratio signal indicative of the ratio of said instantaneous to said average signals, wherein energy bursts in said seismic energy signals provide energy peaks in said energy ratio signal; f. digital peak detector means coupled to said divider means for providing a digital peak-pulse output signal in response to each energy peak which exceeds a given threshold value, each digital output signal having a pulse-width indicative of the duration of the corresponding energy peak; g. peak-rate integrator means coupled to said digital peak detector means for providing an integrated output signal having a level indicative of the period of each digital output signal and the average rate of previously detected digital output signals; h. peak-rate averager means coupled to said peak-rate integrator means for providing an output signal having a level indicative of the average level of the output signal provided by said peak-rate integrator means; i. consistency detector means including comparison means coupled to said peak-rate integrator means and said peak-rate averager means for providing a consistency output signal when the level of the output signal provided by said peak-rate integrator means is within a predetermined range about the level of the signal provided by said averager means; and j. detector decision output means coupled to said consistency detector means for providing a decision output signal when the integrated value of said consistency output signal exceeds a given threshold value.

Claim 27

A seismic intrusion detector comprising, in combination: a. input means for receiving seismic energy signals; b. means coupled to said input means for amplifying and filtering said seismic signals, to provide an amplified version of said seismic energy signals within a predetermined bandwidth; c. rectifier means coupled to said amplifying and filtering means for rectifying the amplified signals; d. first and second integrator means, each coupled to said rectifier means for respectively providing signals representative of the instantaneous and average value of said seismic energy signals; e. divider means coupled to said first and second integrator means for providing an energy ratio signal indicative of the ratio of said instantaneous to said average signals, wherein energy bursts in said seismic energy signals provide energy peaks in said energy ratio signal; f. digital peak detector means coupled to said divider means for providing a digital peak-pulse output signal in response to each energy peak which exceeds a given threshold value, each digital output signal having a pulse-width indicative of the duration of the corresponding energy peak; g. peak-rate integrator means coupled to said digital peak detector means for providing an integrated output signal having a level indicative of the period of each digital output signal and the average rate of previously detected digital output signals; h. peak-rate averager means coupled to said peak-rate integrator means for providing an output signal having a level indicative of the average level of the output signal provided by said peak-rate integrator means; i. consistency detector means including comparison means coupled to said peak-rate integrator means and said peak-rate averager means for providing a consistency output signal when the level of the output signal provided by said peak-rate integrator means is within a predetermined range about the level of the signal provided by said averager means; and j. detector decision output means coupled to said consistency detector means for providing a decision output signal when the integrated value of said consistency output signal exceeds a given threshold value.

Claim 28

The intrusion detector according to claim 11, including analog peak detector means coupled between said divider means and said detector decision output means for providing an analog signal to weight the value of said consistency output signal in accordance with the amplitude of the energy peaks which exceed a given threshold value.

Claim 29

The intrusion detector according to claim 12, wherein said peak-rate integrator means includes means responsive to said digital output signals for providing a time-varying integrated output signal, said time-varying signal having a leading edge wave-form level indicative of the pulse-width of said digital output signals and having a trailing edge waveform level indicative of the duration between successively occurring digital output signals.

Claim 30

The intrusion detector according to claim 13, wherein said time-varying signal is a sawtooth signal and wherein the trailing edge waveform level is controlled by circuit means having a time-constant on the order of 2 seconds.