NAVWEPS REPORT 76^0 



where R.^ is given by 



R]_ and Erji may be determined for three points and R, , R^, R^- computed. A 

 program for the solution on a IM 7^9 computer is given in the Appendix. 

 I4axirami variation from the best straight line 5-20°C of +0.02°C has been 

 achieved. Rj should be approximately 1,000 ohras at 25°C. 



The specifications for the temperature oscillator are as follows: 



Temperature range: O-5O C 



Frequency range: 5,000-8,000 cps 



Sensitivity: 0.01 C/cps 



Accuracy: 0.02°C 



Linearity: maximum variation from best straight line; 

 5-20°C, +0.02°C; 0-50°C, +0.2°C 



Power requirement: 7-2 volts at 25 milliamperes 



Output voltage: 1.0 volts R^is at Z "^ 1,000 ohras 



PRESSURE OSCILLATOR 



The Vibrotron of Borg-Warner Controls, Santa Ana, California, is 

 used for pressure measurements in the SVTP instrument. Pressure is 

 sensed by displacement of a diaphragm that in turn produces a change in 

 tension, and hence, in frequency of a vibrating wire. The advantages 

 of the transducer are that it has a direct frequency output and requires 

 just a simple oscillator to sustain the forced vibrations. The dis- 

 advantages are the temperature drift, long-term frequency instability, 

 and inherent nonlinearity. The frequency of a vibrating wire is given 

 by the formula 



2L / ^ 



where f is frequency, L is length, T is tension, and n is mass per unit 

 length . 



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