220 VAC 



Shipboard 



Power 



-o^o— <x>- 



-o^o— cr-o- 



Isolahon 

 Transformer 



Shipboard AC Power Input I 



HV 

 Power 

 Supply 



— ;: — 



LV 

 Power 

 Supply 



Underwater 

 Cable 



J 28 VC 



-tTJ^ 



-* To 



— ^ Underwater 

 ^ Electronics 



I FFEM Power Supply 



(a) FFEM Primary Power Supply 



Shipboard 

 Supply 



Reverse 

 Discharee 

 Protection 



CCT 



Enerpy 

 Storage 



Ener|^ 



Storage 



CCT 



r 



_j 



LV on 

 Detector 



Liii 



LV Drop 

 Detector 



il*} 



External 

 Selection 



Pulse 



Selection 



Logic 



lai 



Control 

 Logic 



iSl 



Overload 

 Current 

 Detector 



1121 



High Power 

 Switching 

 Circuits 



liiSI 



External 

 Selection 



Mode of 

 Operation 

 Selection 



ta. 



Output to 



■>■ Maximum 



of 5 Grids 



Firing 

 'irculis 



Emergency 



Shut Down 



CCT,,,, 



FFEM Pulser Uttderwater Electronics 



(b) FFEIri Pulser 



Figure 1. — Basic electrical system block diagram. 



Commutatior 

 CCTS 



Lm 



the clock rate by eight. Decoding logic is used to 

 generate the required timing waveforms. 



Pulse selection logic— The pulser has logic 

 for 1-msec output pulses at selectable duty 

 cycles, selectable periods, and distribution to 

 one (two electrode arrays) to four (five 

 electrode arrays) loads in a selectable sequential 

 order. To select a desired pulse pattern the left 

 bulkhead end plate is removed exposing three 

 female plugs; one for selecting pulse pattern, one 

 for selecting the desired load distribution, smd 



one for bench testing. Prewired male mating 

 plugs are inserted to produce the desired 

 performance. 



The pulse parameters available are as 

 follows: The number of on-pulses ^q„ is 2 

 (Sgjj) where S^^ is selectable in seven steps from 

 1 to 7. The number of off-pulses N^ff is (S^^) 

 times (Sgff) where S^jf is selectable in eight 

 steps from to 7 and S^,, is the same as above. 

 The combination of N pulses followed by 

 N^jj-f missing pulses is referred to as a "pulse 

 set." The number of pulse sets distributed to a 



