was also discovered that with pre -equalization, the lower frequencies are 

 lost when an attempt is made to recover them at the surface. When post- 

 equalization is used, the amplifier input noise is too close to the received 

 signal level (amplitudes are equal at approximately 3 MHz). 



Using the results of the analysis and assuming that some degradation 

 of picture quality is acceptable, it appears that it might be possible to get 

 an acceptable TV picture with a 0.4 inch coaxial cable, if optimized equal- 

 ization techniques are used; but it is quite unlikely that the proper power 

 voltage-isolation can be attained. 



The TV portion of the cable transmission aspect of the cable technical 

 barrier will be more precisely defined by (1) conducting a more thorough 

 analysis of different conductors and various equalization techniques, (2) 

 conducting empirical tests on cable segments to adequately define attenua- 

 tion characteristics and power line interference, and (3) conducting em- 

 pirical tests to define an acceptable picture for CURV tj^e operation. It 

 is anticipated that once this is done an acceptable transmission system 

 can be specified using state-of-the-art hardware; however, it is possible 

 that new TV techniques will have to be developed to solve this transmis- 

 sion problem. 



Control and Sensor Signal Transmission 



The third aspect of the transmission problem is the necessity to 

 transmit control signals to the vehicle and receive the signals from the 

 sensors on the vehicle other than the TV. This is presently accomplished 

 by using a myriad of small conductors. Since these small conductors are 

 normally used instead of fillers when making up the control cable, it is 

 difficult to assess the need of combining these signals into a few larger 

 conductors until the power and TV conductors have been defined; but it is 

 highly probable that combining these signals will result in an optimum 

 weight and size of the cable. Making these improvements also has the 

 desired advantage of increasing the system capability, since more control 

 fimctions can be made available and more signals from the vehicle can be 

 transmitted. 



TRANSMISSION SUMMARY 



When the requirements of insulation, ruggedness, strength, flexibil- 

 ity, and nonhosing characteristics are added to the transmission needs 

 for nine power leads, three TV coaxes, and a number of control conduct- 

 ors, the possible growth of the cable size and weight becomes a distinct 

 possibility. 



161 



