SIGNAL INPUT 



D 



PRE-EMPHASIS 

 NETWORK 





VOLTAGE- 

 CONTROLLED 

 OSCILLATOR 





PULSE- 

 FORMING 

 CIRCUIT 



















FIBER 



DIRECTIONAL 

 COUPLER 





INJECTION 

 LASER 



PFM OUTPUT 





















FEEDBACK 









STABILIZER 



Figure 14. Block diagram of the PFM transmitter used 

 in the NOSC PFM brassboard data link. 





FIBER 









AVALANCHE 

 PHOTODETECTOR 





FRONT-END 

 PREAMPLIFIER 





ACC 

 AMPLIFIER 





















t 





ADP 

 CONTROLLER 





PEAK 

 DETECTOR 



















y 



r 





LOW -PASS 

 FILTER 





ONE-SHOT 

 MULTIVIBRATOR 





LEVEL 

 COMPARATOR 

























DE-EMPHASIS 





NAL OUTPUT 





NETW 



ORK 







Figure 15. Block diagram of the PFM receiver. 



32 



