Design of an Ultra Low Frequency Force Ballistocardiograph on the Principle of the Horizontal Pendulum

Abstract
A low frequency ballistocardiographic system based on the principle of the horizontal pendulum is described. By increasing the coupling of the body to the bed and by the use of an extended frequency range accelerometer, ballistocardiograms having clearly defined high frequency components were recorded. The physical principles of such a system are briefly reviewed.