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absolute record corresponds to pounds per square inch and the signals 

 of the differential records to pounds per square inch differential 

 per inch of gage length. It is immediately obvious that the signal 

 of dPl is extremely erratic with high frequency energy that would 

 alias into the energy spectrum. At other times, it agrees in form with 

 dP3 satisfactorily although it is shifted downwards because of the 

 large mean value subtracted from the record. This large mean is 

 apparently the result of the large positive-valued high frequency 

 oscillations. This disturbance is intermittent and does not appear 

 in all of the records from dPl. These high frequency oscillations 

 have never been observed on the strip chart output at the FRF, and so 

 it is possible that the problem lies within the digitization of the 

 s ignal . 



The records of dP2 and dPA agree well as expected for two 

 collinear gauges. There are slight phase and amplitude differences 

 as would be expected since the two gauges are separated in space a 

 finite amount. 



There is reasonable phase agreement between the dP2, dP3, and 

 dP4 signals with those of the absolute gauge — as best as can be 

 seen. Again, one expects a ninety degree phase difference between 

 the absolute and differential signals. 



