Abstract
This paper deals with the practical applications of the mutual induction principle for the simultaneous measurements of the static and dynamic displacements (l0±Δl) of the soft body tissuein vivo, such as heart, vessel, intestine, uterus, respiratory system and etc. The advantages of this method are based on the qualitative detection of displacements by tiny and light weighed couple of coils pasted on the surface of the tissuein vivo. One of the paired coil behaves as a transmitting coil operated around crystal controlled 450 kc and the amplitude modulated signal by distance is received by another coil and reproduced into the DC distance signal through IFT circuit. The results demonstrated stable and linear characteristics (± 1% error, i. e. less than 10 micron in distance) with high conversion ratio (4 volts/mm). Practically the pressure-diameter relationships of the vessel and heart wall, peristaltic movements of the intestine or uterus, and respiratory excursion of chest wall are continuously recorded. Three dimensional measurements are done by using three different exciting frequencies, namely 400, 450 and 500 kc into three couples of coils without any interferences among them.
