Multichannel system for seismic signature determination

• US 3,913,085 A
• Filed: 01/16/1974
• Issued: 10/14/1975
• Est. Priority Date: 01/16/1974
• Status: Expired due to Term

• Current Assignee: Arnold J. Farstad
• Original Assignee: Arnold J. Farstad
• Inventors: Farstad, Arnold J.
• Primary Examiner(s): Trafton, David L.
• Application Number:
  US05/433,955
• Time in Patent Office: 636 Days
• Field of Search: 340/261,16R,15.5DP
• US Class Current: 367/136
• CPC Class Codes: G08B 13/1663 using seismic sensing means

Abstract

The output signals of an array of seismic transducers such as geophones buried beneath the surface of the ground to provide perimeter intrusion protection, are supplied to a multichannel processing circuit which initially isolates that frequency portion of the signals attributable to intrusions in general, and subsequently determines the various repetition rates within the preselected frequency range to characterize the type of intrusion, i.e., a single pedestrian, a group of pedestrians, a vehicle, animals, etc.

Claims

1. A multi-channel signal processor for developing a signature of an earth disturbance in response to seismic signals, comprisiNg, first means adapted to respond to seismic signals by developing a pulse output signal corresponding to the presence of a predetermined frequency component of said seismic signals, and a plurality of pulse repetition rate channels operatively connected to said first means, each of said channels including a narrow band amplifier to generate output signals in response to a different predetermined repetition rate of said output signals developed by said first means and an analog to digital converter means operatively connected to the output of said narrow band amplifier to convert the output signals of said narrow band amplifier to digital pulses and processor means operatively connected to said pulse repetition rate channels to respond to the digital output pulses produced by the respective channels to develop a signature of an earth disturbance based on the distribution of digital output pulses from the respective channels.

2. A multi-channel signal processor as claimed in claim 1 wherein each of said pulse repetition rate channels produces a count output indicative of the presence of the corresponding pulse repetition rate in said output signal of said first means, said processor means including count analyzer means operatively connected to said plurality of pulse repetition rate channels to analyze the distribution of counts in the respective pulse repetition rate channels to identify the disturbance producing seismic signals.

3. A multi-channel signal processor as claimed in claim 1 wherein said first means includes a detectorfilter circuit means for developing an output signal in response to frequency components of said seismic signals occurring within a range of 30 to 50 hertz.

4. A multi-channel signal processor as claimed in claim 1 wherein said predetermined pulse repetition rates are in a range of approximately 1 to 5 pulses per second.