Figure 2. — Freshwater Fish Electro-Motivator (FFEM) pulser with and without protective aluminum housing. 



given electrode load N^ist before switching to 

 another load is selectable in 15 steps from 1 to 

 15. Also, the order of pulsing electrode pairs is 

 selectable after N^ist sets of pulses to a given 

 load. The above pulse parameters are all based 

 on the 1-msec on, 7-msec off basic pattern. 



As examples of pulse parameters possible, we 

 will give situations where a single load (2 elec- 

 trode arrays) and two loads (3 electrode arrays) 

 are fired (Figure 5). For a single load, suppose 



Son = 2, Soff = 3, and Ndist = 1- The output to 

 this load would appear as shown in Figure 5a. In 

 this example, the pulse set Non and Noff equals 

 10 and produces a total pulse period of 80 msec 

 and an effective duty cycle of 40%. In all situ- 

 ations the number of basic pulse groups (No,^ 

 Noff) can be varied with Non = 2X and Noff = 

 YX where X can be selected 1 through 7, and Y 

 can be selected through 7. For the basic pulse 

 pattern in Figure 5 with tp (total pulse or pulse 



