DESIGN OF A TWO-DIMENSIONAL BALLISTOCARDIOGRAPH 1

Abstract

From a theoretical analysis, it is shown that a high frequency ballistocardiographic table must be used if the motion of the table is to reproduce the forces acting upon it. A Fourier analysis of 3 ballistic curves obtained on a healthy young adult is also offered to demonstrate that a table with a natural frequency of at least 15 cycles/sec. must be used with a higher value of from 25 to 30 cycles desired. The damping should be viscous and should be sufficient to insure that the table is between 50 and 100% critically damped with the subject on the table. The design and construction of a ballistocardiograph with 2 degrees of freedom corresponding to the frontal plane of the body, is described in detail, a record taken with this instrument has been illustrated and the nature of the side component has been discussed.