strung out on a 6000-foot cable, no detailed consideration 

 has been given to the display and recording problem. In fact, 

 no aspects of the display, recording, or processing in the 

 system shown are peculiar to the use of a deep-towed instrument 

 chain. The display and recording equipment indicated in the 

 block diagram may therefore be considered as illustrations of 

 a wide class of available equipment, 



A feature of the digital display and printer shown is 

 that the digit representing the temperature or depth is 

 obtained directly by counting the number of cycles in the 

 FM gage signal for a selected interval of time. The display 

 and print-out may be made direct reading in, for example, 

 degrees Centigrade simply by proper selection of the counting- 

 time interval and a "bias count" which the counter adds to or 

 subtracts from the total count of cycles occurring in the 

 counting-time interval. The only requirement on the relation 

 between themeasured quantity and the gage-signal frequency 

 is that it be a linear one. As an example, suppose that the 

 gage-signal frequency is 6200 cycles per second at 0° C, 

 11,000 cycles per second at 30° C, A decimal counter which 

 counts for 0,625 seconds and subtracts 3875 from the result-- 

 ing count will read out temperature directly in hundredths of 

 a degree C, 



The analogue temperature plotter indicated employs conven- 

 tional circuitry to convert the frequency of the gage signal 



87 



