Abstract: The technique for replacing certain components in a linear accelerometer with an arrangement compatible with all of the other components making up the accelerometer is disclosed herein. The components that are replaced include a potentiometer and mechanical acceleration sensing means which cooperate with one another and which operate on a DC excitation voltage for producing an initial voltage dependent on both the acceleration sensed and the excitation voltage. The arrangement replacing these latter components include acceleration sensing means operating on the same DC excitation voltage for producing an initial voltage which is dependent on the acceleration but which is independent of the excitation voltage and means for adding a percentage of the excitation voltage to this latter voltage for providing a voltage which is dependent on both the acceleration sensed and the excitation voltage, thereby making the arrangement compatible with those components in the accelerometer which have not been replaced.

Abstract: A high frequency pickoff is disclosed having two spaced inductors electrically connected in series and a capacitor connected in parallel with the inductors, thereby forming a parallel resonant circuit. A conducting member is mounted for motion in the space between the two inductors. A pair of transistors are mounted in push/pull configuration to alternately connect first one end and then the other of the resonant circuit to a source of electrical energy. The source disclosed is a current source for matching the high impedance of the parallel resonant circuit. When the electrical energy is switched at substantially the resonant frequency of the parallel circuit, differential motion of the conducting member relative to the inductors provides differential amplitude output at the frequency of resonance of electrically opposed ends of the resonant circuit.

Abstract: A computer adjunct is described which is used in combination with an impedance plethysmograph. The impedance plethysmograph provides signals related to conductance in a biological segment and related to deviation from a quiescent resistance level in the biological segment as body fluids are pumped therethrough in a pulsatile manner by the pumping action of the heart. The deviation of the segment resistance contains artifact signals such as those imposed by movement or breathing. The computer adjunct contains means for providing a signal indicative of heart pumping rate and circuit means for measuring the level of the artifact signals once each heart pumping cycle and generating a correction signal related thereto. The correction signal is thereafter applied to the deviation signal for reducing error induced by the artifact signals. The heart rate signal is conditioned to obtain a signal related thereto which is averaged. The corrected deviation signal is also averaged.