...The pulse will produce a magnetic field generated by the searching coil, and becose of eddy currents, the target will produce a very low corresponding voltage at the coil terminals. The mode this signal decay depends of target characteristics ( form, type, material ) and the distance. This is the signal we need to analyze, so it is supressed by two antiparallel diodes and passed to an operational amplifier . After amplification, the analog signal is read by one of analog input of Raspberry Pi Pico board and is analized by the software. This poccess is repeatedly for many times per second.