cycles amplifier self noise rather than se4 noise sets the limit for 

 minimum signals. 



The dotted curve of Figure 6, shows the maximum input voltage 

 level at which limiting of the output voltage begins. The solid curve 

 shows the dynamic range, i.e., the maximum input voltage minus the sum 

 of the self noise and the expected minimum sea noise. 



5. Cable. 



(a) Description 



The inshore end of the cable consists of 3800 feet of heavily 

 armored four (4) conductor cable of approximately 1.25 inch diameter, 

 which is joined through a splice box (see Figure 7) to two lengths of 

 type PBW-0216 2 conductor armored distribution wire of approximately 0.3 

 inch diameter. One length of PBW, 2600 feet, is connected to the shallow 

 hydrophone. The other length, 10,600 feet, is connected to the deep 

 hydrophone. The electrical characteristics of the quad and the PBW cable 

 are similar and the characteristics below apply equally to both cable 

 types o 



(1) Resistance 51.9 ohms/ loop nra. 



(2) Capacitance 0.0983 ;uf/nm, 



6 . Laboratory Equipment . 



(a) Functional Description 



The block diagram. Figure 8, illustrates the various functions 

 which the shore^based equipment can perform. The following enumerates 

 some of the system's features: 



(1) Transistorized, battery operated, variable gain terminal 

 amplifiers which terminate the cable through matching transformers. 



(2) Oscillator, meter and attenuator for reference calibration 



signals . 



(3) A two track tape recorder with continuous monitoring 

 capability. 



(4) Capstan drive power from an external, precision fork 

 controlled amplifier. 



(5) Provision for "dubbing" from the two track monitoring 

 recorder to an external recorder or vice versa from any suitable external 

 source. 



