punched tapes, or even punched cards. Inasmuch as the system would be 

 geared to signals within the audible frequency range, it would appear 

 that it also could be readily adapted to receive acoustic signals trans- 

 mitted through the water. 



In summary, the apparent advantages of this system requiring further 

 investigation are: 



1. Accuracy and Ease with which Signals Can Be Relayed 



Inasmuch as the signals are not amplitude- dependent they are not 

 dependent upon the resistance of the transmitting cable. It would appear 

 that radio transmission also would be accurate and easy. Additionally, 

 signals could be transmitted through water along a single, insulated, 

 steel cable, or acoustically from transducer to hydrophone. 



2. Flexibility in Converting and Recording Signals 



The signal can be recorded directly on single- channel magnetic 

 tape for direct analysis, for later conversion to visual display, or for 

 digitizing on paper tape, cards, or multi- channel magnetic tape for 

 computer analysis. Since the signal code is not in terms of current or 

 voltage, simultaneous recording in more than one form is possible 

 without the need for precise voltage controls. Simply by recording 

 intermittently, sampling at any desired interval can be programmed. 

 Choice of digital or analog data also is possible at any point. 



3. Simultaneous Transmission of Several Elements by Selection of 

 Appropriate Band- Widths 



With a range in frequency from 50 to 15,000 cps and the assumption 

 that frequency can be determined to an accuracy of 1 cps, a single 

 parameter could be transmitted and recorded to at least four signifi- 

 cant places. Two to fifteen parameters could be transmitted and recorded 

 to at least three significant places, and so forth. In addition, by indicat- 

 ing by code the type of information which follows and then staggering 

 the parameters transmitted, and greater flexibility can be achieved. 



4. Direct Annotation of the Record By Voice or Code 



5. Availability of Methods for Converting Resistance to Frequency 



This system seems ideal from the standpoint of flexibility in the 

 choice of records, i.e., analog or digial. On the input side, conversion 

 of resistance to frequency for a temperature sensing element can be 



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