92 



The calibration curves were generated from the strip chart 

 output reproduced in Appendix B. The calibration chamber was 

 pressured, allowed to leak slightly, and the chamber and DPG 

 transducer readings taken from the strip chart at the point before 

 the system was loaded again. The response time for the DPG 

 transducers was determined by measuring the passage of time between 

 loading events as reported by the chamber transducer and the DPG 

 transducer on the strip chart. Each transducer appears to respond in 

 an acceptably similar short time period. 



A. Power Supply Sensitivity 



Each of the transducers demonstrated satisfactory 

 insensi tivi ty to power supply voltage fluctuations except dPl. 

 Whereas the absolute and dP2, dP3, and dPA transducers were 

 unaffected by voltage changes from 20 to 26 volts, the output of dPl 

 decreased in an unexplained manner at excitation voltages below 22 

 volts. 



5. Transducer Drift 



The absolute and dPl, dP2, and dP3 transducers proved steady 

 in output with steady loading. However, dPA intermittently and 

 erratically drifted during the second set of bencb calibration tests. 

 It is assumed that such drift will be simply interpreted as a long 

 period wave by the FFT analysis of the data. But the inability of 



