Application Topics of Amorphous Wire CMOS IC Magneto-Impedance Micromagnetic Sensors for I-o-T Smart Society

Figure 5

First, differential output is taken for 2 adjacent MI sensors apart at a 50 mm interval in a traverse direction and then amplified. In this step, most ambient magnetic noises including geomagnetic field is eliminated so that sufficient amplification would be possible. Then, the differentials relative to the car’s traveling distance are taken. In this step, a particular marker pattern is distinguished, since a marker field has sharp up and down gradients, against the traveling distance. After the step, the signals are subjected to a band pass filter which is adjusted to the cycle in which the consecutive marker signals are coming in as the car travels forward. In the above manner, (N-1) output are obtained from N sensors. Then the peak value of each detected marker pattern is detected, and those (N-1) peaks are connected next to each other.