Metal detector having target characterization and search classification

Abstract

A metal detector is provided with circuitry for producing a plurality of vector signals derived from a target signal. Each of these vector signals corresponds to a phase characteristic of target signals. These vector signals define phase ranges which correspond to classifications of targets. Upon detection of a target signal, the metal detector generates first and second phase detected signals which in turn generate a plurality of vector signals. These vector signals are digitized and within a microprocessor a determination is made through slope analysis to determine which range includes the principal phase of the detected target signal. The vector signals which define the identified range are then utilized in algebraic calculations to define one of a plurality of subphase ranges within each range. This identified subphase range identifies a segment in a linear display which is illuminated to show the determined characteristic for the detected object. An operator can program the detector to select or reject target objects having certain electrical characteristics and this is likewise displayed to the operator. When the detector determines that a target signal has the same characteristics as selected by the operator, an audio output is generated. The display provided to the operator enables the operator to easily select or reject specific signal characteristics pertaining to certain types of targets.