Wave heights are recorded from an EDO 255B transducer mounted In the trans- 

 ducer housing. The distance to the surface is recorded approximately every 0.6 

 second. These data are adequate to allow spectral analysis of wave heights. 



C. Signal Conditioners 



In the case of depth and sound velocity transducers, outputs are frequency 

 modulated . The thermister bridge output is converted to FM by the use of a linear 

 voltage to frequency converter. 



The depth transducer output is linearized by the use of an oscillator-mixer 

 driven by the depth transducer, it's output is fed into the time base of the depth 

 counter. This counter is modified to count backwards since the depth transducer 

 output is inversely proportional to depth. Special counter reset dials allow the 

 counter to be reset to any desired number, thus effecting an automatic zero suppress 

 operation . 



D. Digitizers 



Signals from the transducers are converted to absolute units and digitized 

 by the use of two variable time base counters and a time interval counter. 



Echo sounder outgoing pulses and return echo gate an electronic counter, 

 resulting in digitized values of distance to the surface in feet and tenths, or metric 

 units if desired. 



Outputs from the clock, calendar, and manual inputs are in digital form and 

 require no further digitizing. 



E , Recorders 



The scanner is a six-digit, six-channel stepping switch which allows the 

 digitized outputs of each sensor to pass in sequence to the digital recorder or tape 

 punch coupler. 



The digital recorder is operated by the scanner and provides a printed record 

 similar to a cash register receipt of all variables sampled by the scanner. 



The paper tape punch is connected to the scanner by means of the coupler. The 

 coupler's function is to convert the parallel data from the scanner to the serial form 

 required by the tape punch. Both coupler and tape punch operate directly from the 

 scanner and cannot be used simultaneously with the digital recorder. The punched 

 tape format is compatible with the electronic computer and the Flexowriter. 



