An analog method is described for solving some of the mechanical problems associated with the recording of ballistocardiograms. An L‐C‐R circuit is used as the analog of the body coupled to a fixed table. It is concluded that no technical obstacles exist to the widespread use of ballistocardiography, through equipment similar to that described here. Clinical problems in the interpretation are not discussed.
REFERENCES
1.
Indeed, this is the way that ballistocardiography was discovered by Gordon in 1877.
2.
S. A.
Talbot
and W. K.
Harrison
, Circulation
12
, 577
, 845
and
1022
(1955
).3.
It is necessary (and simple) to disconnect some condensers that are included in the circuit of the Dock sensor. It is odd that they were included in the first place. Of course, any velocity sensor can be used with similar circuitry, taking care only that its output impedance is much greater than the input impedance of the transistor amplifier (about 100 ohms in this connection). Thus the sensor acts as a current generator for the transistors. We only used the Dock sensor because we had one easily available.
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© 1956 American Institute of Physics.
1956
American Institute of Physics
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