| 摘要 |
Portable concealed structure locating and surveying translator apparatus, useful for tracing the bearing and lay of cables, pipes, and other expansive structures. The translator responds to the electromagnetic field radiating from a buried structure which is excited by a constant amplitude, fixed frequency high frequency a.c. signal. The translator is directional, providing bearing indication in its preferred form. Two noncoincident receiving loops, or inducers, are closely oriented to receive the structure radiated field lines with differing positional related efficacity. The received signal levels produced in each of the receiving loops is coupled with a receiver which includes a provision for the automatic, digitally advanced, sequential step-by-step change in overall sensitivity through a range of discrete values of responsiveness. Each discrete response value recurs at a related, finite repetition rate which results in an overall characteristic stepped swept gain effect, thereby producing instantaneous variegated values of signal level which are detected as finite threshold levels and thereby usually adapted into a pair of audio frequency tones which, when coupled to an operator's ears, serve to give a stereotonic effect with the balance of apparent pitch therebetween indicating on-course bearing, while the relative pitch imbalance wrought between the right and the left ear associated earphone gives a sense of bearing directionality to the operator.
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