Table 9-2 



A Raw Data Record from the ACP/Pressure sensor 



FF 00 00 00 



00 00 00 00 00 



F2 FO EF EB F2 

 EC E7 EF FO FO 



EF E9 EE E3 EC 

 E3 EB EA EC DC 



E2 DF C9 E2 DF 

 DD D5 D2 D6 E3 



E3 CC D3 D7 C8 

 DO CF D5 D9 D8 



C9 C3 C8 CA C5 

 C8 B7 BA B4 B4 



BE AF BB BA AB 

 B8 B9 AA B6 AB 



A3 96 99 A8 8F 

 88 8A 81 90 A8 



9A86 91 80 79 

 6A75 7C7B 6D 



6E 67 71 77 69 

 78 5B 6F 6F 6A 



66 6F 69 62 4B 

 4B 58 55 4A 55 



50 47 5F 67 93 

 AB F6 FF FE DB 



reflected acoustic signal with distance from the face of the transducer. The 

 extent of the dip is adjusted by changing the external gain of the transducer 

 preamplifier. The sawtooth nature of the curve is due to the independent 

 offsets of the two A/D converters processing the ACP data stream. 



Another way to look at the raw ACP data is to examine a histogram of the 

 signals in each bin over the averaging period. Figure 9-9 shows this at four 

 points in the profile, where each range bin is represented by the average of 

 three range bins, including one above and one below each point. The four 

 points correspond to the vertical positions of the sampling points of the BASS 

 velocity values. The figure shows that reflected intensities obtained at each 

 range bin are distributed normally at all four points within the profile. If this 

 were not the case, using average values to represent the concentration profiles 

 might be questionable, or the sampling rate could need adjustment. Similar 

 figures are shown in Figures 18-114 of Appendix I (contained in Volume II of 

 this report). 



Chapter 9 The Ohio State University Measurements 



171 



