be lost in the re-record process. A magnetic-tape signal eraser will be 

 incorporated to remove the signals from the original tape after it is 

 transcribed onto the other reel. The original tape will then be sent back 

 into the field for re-use. The transcribed tape is then 1/32 of its 

 original length and after being converted to loop form (appropriate to 

 each run), it is ready for analysis. During the re-record period, the 

 information will be simultaneously transcribed onto graphic chart paper, 

 as at present, and a book of the experiment will be prepared and filed. 

 After the loops are played through the analyzer, they will also be stored, 

 as at present . 



Two changes are planned for the analyzer; one is simple and direct, and 

 the other requires some careful electronic engineering. As mentioned in 

 the preceding section, the two most popular modes of SEADAC operation are 

 computation of the spectral density function and computation of the total 

 energy in the signal. In the present system, each calculation can be 

 made either successively on one analyzer or simultaneously on both analyzers, 

 If each analyzer can be made to perform both operations simultaneously, 

 analysis time will be cut in half. The way to accomplish this is to 

 incorporate an additional power integrator and recorder into each analyzer. 

 This was done experimentally with the existing equipment and the result 

 appears in Figure 13. The spectral density curve and integrated curve 

 marked "A" represent successive analyses on a single analyzer, whereas 

 the curves marked "A + B" represent simultaneous analyses of the same data 

 on the same analyzer with the addition of the power integrator and recorder 

 of the other analyzer. The small differences are attributed to the different 

 gains of the two systems and are corrected by the calibrations. The good 



26 



