Mechanocardiograph Sensors Using Amorphous Star-Shaped Core Multivibrators

Highly stable and accurate mechanocardiograph sensors are presented using linear magnet-displacement sensors with a star-shaped amorphous core multivibrator. 2N zero-magnetostrictive amorphous wire cores are combined in a new star-shape configuration, in which the influence of external disturbance fields such as terrestrial fields is almost completely eliminated and the signal field generated by a small magnet is stably detected. These linear displacement sensors can detect the displacement of a magnet through about 3 mm with a drift of less than 0.2 ¿m. Mechanocardiographs of a heartbeat, a phonocardiograph, and blood-vessel pulsation are stably and easily detected by fixing a small magnet on the chest wall or the blood-vessel position, combined with a non-contact type displacement sensor.