Sec. 1-3] 



MECHANICAL INPUT TRANSDUCERS 



91 



1-3. Transducers for Velocity or Acceleration 



a. Differentiating Systems . Electric signals which are proportional 

 to the velocity, the acceleration, or to a higher time derivative of a 

 displacement are usually formed by electrical differentiation of the 

 displacement transducer output, as shown in Fig. (1-3) 1. A method, 



V 



Fig. (1-3)1. Circuit for obtaining output signals proportional to velocity and 

 acceleration from displacement transducers. 



based upon this principle, which permits the measurement of ac- 

 celeration and force from displacement-proportional signals (meas- 

 urement of the force with which the extrinsic ocular muscles move 

 the eyeball), is described by Lion and Powsner. 1 



Instead of starting out from an electric signal analogous to a move- 

 ment or a force and forming the derivatives electrically, as shown in 



Fig. (1-3)2. Circuit for obtaining velocity and displacement proportional 

 signals from acceleration-proportional input signals. 



Fig. (1-3)1, one can also produce by mechanical means a displace- 

 ment that is proportional to a velocity or an acceleration and convert 

 this displacement into an electric signal. For instance, under the 

 influence of an acceleration, a mass may exercise a force or cause a 

 displacement which is proportional to the acceleration. The force or 



1 K. S. Lion and E. R. Powsner. J. Appl. Physiology, 4, 276 (1951); sec also 

 Pv. J. Brockhurst and K. S. Lion, Arch. Ophthalmol. {Chicago), 46, 311 (1951). 



