US Patent 7740130 Digital processor sensor loop detector and method

A digital processor for use in a conveyor belt rip detector, which provides excitation signals at a selected frequency to inverted and noninverted sensor loops on a conveyor belt and then, detects corresponding received signals from the sensor loops. The digital processor then performs FFTs on the corresponding received signals to provide respective received signal frequency spectrums. Next magnitude and phase values of the selected frequency in the respective received signal frequency spectrums are used to determine a qualitative state of the sensor loops. The selected frequency has a lowest detected ambient noise level, and the magnitude value is a normalized magnitude value.