Design and its application of the f(n)-zeta chart capable of direct readout of the highest frequency indicating the limit of obtaining distortion-free waveforms.
We have already reported that the highest frequency (f(h)) could serve as an index for evaluating the fidelity of pressure waveform derived via a catheter manometer system and be read off by the f(n)-zeta chart. Fh is determined by the natural frequency (f(n)) and damping coefficient ( zeta ) in the frequency characteristics of the system. Inversely, f(h) determines two pairs of f(n) and zeta in the f(n)-zeta chart, one in the case of zeta < 0.7 and the another zeta > 0.7. Then, each pair of f(n) and zeta determines respectively the resonant frequency (f(r)) and its amplitude (Ar) ( zeta < 0.7), or the corner frequency (f(c)) and its amplitude (Ac) ( zeta > 0.7) in the frequency characteristics. Thus, the point (f(r), Ar) or (f(c), Ac) represents the position of f(h) projected in the frequency characteristics. Repeating the same operation for other f(n) and zeta corresponding to the same f(h), yields the curve of f(h) in the frequency characteristics. Calculations for other f(h)'s provide a group of curves. Frequency characteristics of pulmonary artery catheters were measured and overwritten thereupon, resulting in f(h)'s to be from 1.2 to 3.2 Hz. These results were in agreement with that calculated by the conventional method.
Fukuyama
Haruo
H
Department of Anesthesiology, Tokai University School of Medicine, Kanagawa, Japan. h-fuku@is.icc.u-tokai.ac.jp
Kinefuchi
Yoshio
Y
Saitoh
Satoru
S
Kanazawa
Masahiro
M
Shimada
Masato
M
Suzuki
Toshiyasu
T
D001795:Blood Pressure Determination / Q000295:instrumentation / Q000379:methods*; D003627:Data Interpretation, Statistical; D006801:Humans; D007700:Kinetics; D008365:Manometry; D008433:Mathematics; D011651:Pulmonary Artery / Q000502:physiology; D013696:Temperature