WEINSTEIN: EXPLOSIVE SOUND-SOURCE STANDARDS 



problems, some of which have been touched on (Christian, these 

 Proceedings). However, we shall examine some of the concepts which 

 support 1 dB as a reasonable goal against which to gauge our 

 performance. 



Suppose we are considering the design of a surveillance system 

 which will make detections at long range where the propagation loss 

 follows cylindrical spreading. An uncertainty of ± 1 dB translates 

 into an uncertainty in area coverage of about 50 percent; a not 

 inconsiderable factor in estimating costs. 



Suppose we wish to optimize the geographical location or depth 

 of such a system. One might perform an experiment for simultaneous 

 measurement of propagation loss at a number of sensor locations. We 

 want to know the propagation loss difference to within one decibel 

 for the same reason. 



In a somewhat different context, fluctuations in propagation 

 loss are of considerable interest. If true fluctuations have a 

 standard deviation of about 3 dB , one cannot stand an uncertainty of 

 more than about 1 dB before the results are significantly degraded. 



Thus, the data needs indicate the desirability of obtaining 

 propagation-loss data which are accurate to about one decibel . 



SOURCE-LEVEL UNCERTAINTY 



Consider the accuracies which can be achieved. First, the 

 uncertainty in source level. 



Figure 1 shows source levels in 1/3-octave bands for 1.8-pound 

 charges detonated at 60 and 300 feet. These three data sets illus- 

 trate the range of values with which we are confronted. The spread 



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