WEINSTEIN: EXPLOSIVE SOUND-SOURCE STANDARDS 



some frequency. The question is what is the signal-to-noise ratio of 

 each successive arrival? That's not directly inferrable from the broad- 

 band pressure versue time history you showed. 



You may have a very large signal-to-noise ratio based on peak 

 amplitude but at some particular frequency have a very poor signal-to- 

 noise ratio for that same arrival. So the point is, you may have some 

 very marginal signal-to-noise ratios in that band arrival by arrival 

 and yet have a total energy that is misleading. 



Dr. Weinstein: Yes, I understand what you are saying. Why don't 

 we consider the time series of the signal in a third-octave band 

 already? If we were to look at a part of it, it would have a much 

 higher signal-to-noise ratio than we would have for the total. Yes, 

 there may be some arrival which we are not seeing which has a poor 

 signal-to-noise ratio. But you have to recognize that we have time domain 

 problems here. This harks back to the question of overloads in the 

 system. Can you take an overloaded signal and make some estimate as 

 to what the propagation loss level has to be at which you will overload? 

 Well, the answer is you can't because the propagation loss depends 

 upon the multistructure. The overload depends upon the individual peak. 



Dr. S. C. Daubin (Rosenstiel School of Marine and Atmospheric 

 Science, University of Miami) : I want to ask a question related to 

 Mr. Hamilton's question of variability from shot to shot at the same 

 depth. Could you tell me what the manufacturing tolerance in a SUS is 

 regarding the weight of the charge? Is it 1.8 pounds plus or minus 

 what? 



Dr. Weinstein: 1 don't remember the number precisely, but my 

 recollection is it's going to be plus or minus a couple of tenths of a 

 pound, something of that sort. But the problem doesn't lie in that 

 tolerance. The problem lies in how the SUS is manufactured. 



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