Abstract: Method and system of perpendicular magnetic recording and reproducing with ultra-high density for use in computer storage, audio, video recording euipment. Marks, as logical “1”-s are recorded at predeteremined distance from one another and their magnetic axes oriented in the opposite directions, as logical “0”-s are non-magnetized, forming pattern similar to chess-board order with the zero potential lines, eliminating crosstalk. Interaction “head-medium” is based on non-contact magnetic modulation, eliminating tribology problems. System may compose single or multi track medium, transporting linearly or rotating, with the immovable, quasi-immovable or scanning bi-polar or uni-polar magnetic heads, which have extremely small pointing conjugation area for interation with superminiature dimensions of magnetic fields of marks.

Abstract: Device for measuring intensity of magnetic field, displacement, speed and acceleration of magnetized and ferromagnetic objects in external magnetic field including source of external magnetic field, sensor sensing intensity of magnetic field and having toroid type ferromagnetic core, primary and secondary windings, circuitry for activating primary winding with alternative current, circuitry for detecting and measuring peak voltage of the output pulses at the secondary winding, components controlling intensity of external magnetic field. Displacement of controlled objects in external magnetic field changes intensity of the magnetic field near the sensor. This displacement is measured by measuring peak voltage of the output pulses. The alternative current in primary winding induces positive and negative output pulses in secondary winding, remagnetizing the core along the hysteresis loop.