[Show abstract][Hide abstract]ABSTRACT: New non-contact type linear-displacement sensors are constructed using a magnetometer combined with a small magnet. The magnetometer contains an amorphous-wire-core multivibrator bridge. High linearity of the sensor output versus the magnet displacement is realized by cancelling the nonlinearity of the field versus displacement of the magnet using the saturation curve of the magnetometer. These sensors detect magnet displacements of 1 μm - 6 mm at frequencies 0 - 4 kHz. Mechano-cardiograph, that is, Phonocardiograph and Sphygmograph use a new non-contact sensors by attaching a small magnet to the chest wall without disturbances that have been a problem when using conventional microphone type sensors. These non-contact type sensors are expected to add easy manipulation to the mechanocardiograph, similar to the electrocardiograph, and become an effective tool for diagnosis of cardial functions.
Article · Oct 1985 · IEEE Transactions on Magnetics
[Show abstract][Hide abstract]ABSTRACT: New con-contact type linear displacement (oscillation) sensors are presented which combine a two amorphous-wire core multivibrator bridge with a small magnet. The nonlinearity of the relationship between magnetic field from the magnet and the distance between the detection point and the magnet is cancelled by utilizing the saturation characteristics of the amorphous-core magnetometer. Linear ranges as large as 8mm have been obtained using a zero-magnetostrictive amorphous wire (made by UNITIKA Co.) of 44mm in diameter on which two 20mm long coils are placed separately. The cut-off frequency is about 4 kHz in the displacement sensor, and the minimum detectable displacement is about 1 μm.A new sensing technique is developed using these non-contact linear displacement sensors for mechanocardiography for cardio-function diagnosis combined with the electrocardiograph.
Article · Jan 1985 · Journal of the Magnetics Society of Japan