



































METER 





TIMING 

 CIRCUIT " 







TRANSMIT 

 DRIVER 







t 















— 



o 







1 















SAMPLE/ 

 HOLD 





AMP 





COIL 





-* 



















BATTERY/ 

 POWER 

 SUPPLY 





















RECEIVER/ 

 AMPLIFIER 







^' 















EARPHONES 



Figure 8 

 Pulse-induction metal detector block diagram. 



Table 2. Electronic Characteristics Analysis 



Characteristic 



Garrett XL500 



White's PI-1000 



Fisher Pulse 8 



Output Pulse Width 



160 microseconds 



30 microseconds 



400 microseconds 



Output Pulse 

 Repetition Rate 



9.5 milliseconds 



300 milliseconds 



11.5 milliseconds 



Energy Per Pulse 



4.6 millijoules 



25 millijoules 



13.8 millijoules 



Power Supply 

 Voltage 



9.6 volts DC 



9.0 volts DC 



8.2 volts DC 



Power Supply 

 Current 



110 to 125 

 milliamps 



65 to 80 milliamps 



310 to 325 

 milliamps 



Response Time 



approximately 100 

 milliseconds 



approximately 500 

 milliseconds 



approximately 200 

 milliseconds 



Receiver Sensitivity 



unable to measure 



unable to measure 



unable to measure 



Battery Life 



9 hours on fully 

 charged batteries 



12 to 15 hours on 



six nonrechargeable 



"AA" batteries 



4 hours on fully 

 charged batteries 



12 



