| 摘要 |
A locator, 800, for locating a buried electromagnetic marker, comprises a transmission antenna, 110, for generating an oscillatory magnetic field to couple with the electromagnetic marker and a test magnetic field to perform a validation test on the locator to check that the transmission of the antenna is operating within calibrated limits, a reception antenna, 120, to receive the oscillatory magnetic field emitted by the electromagnetic marker and the test field, and an analogue to digital converter, 144, for generating a digitised test signal from the detected test signal. The locator may have a memory to store calibration data and a processor, 150, to calculate a validation value from the test signal. The oscillatory magnetic field may comprise a plurality of pulses. A certificate may be generated if the validation value is within predetermined limits. A computer readable medium that carries instructions may be present to cause the processor to carry out the method for calculating the validation value. |
