Research/Patents/US 5025218
US 5025218

PULSED FIELD SYSTEM FOR DETECTING THE PRESENCE OF A TARGET IN A SUBSURFACE ENVIRONMENT

Assignee

Filed

Apr 23, 1979

Granted

Jun 18, 1991

Location

CA US

Abstract

In a method and apparatus for searching a subsurface environment to detecthe presence of a target therein, an electromagnetic field is emitted which comprises successive electromagnetic pulses of selected duty cycle, the time interval between pulses comprising a zero emission interval and a sampling interval, the sampling interval following the zero emission interval, and the polarity of the pulses of the emitted field alternating at a selected alternating frequency. The emitted field is projected into the environment from a selected location, and the electromagnetic field proximate to the selected location is sampled during each of the sampling intervals to provide a train of proximate field samples. The train of proximate field samples is spectrum analyzed to determine whether or not the field proximate to the selected location contains a component having a frequency which is equal to the alternating frequency.

Source: Google Patents

35 USC §181 Secrecy Order

Imposed

Oct 2, 1981

Rescinded

Nov 1, 1990

Duration

9 years, 1 month

Inventor

  • 1CLARENCE F. RAMSTEDT

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Back to patent indexSource: USPTO 35 USC §181 secrecy order records