FREQUENCY SHIFT TELEGRAPHY 



275 



-4-3-2-1 1 2 3 4 



FREQUENCY IN KILOCYCLES PER SECOND 



(FROM MID-BAND) 



Fig. 6. — I.F. selectivity characteristic of radio receiver. 



50 



40 



30 



20 



10 - 



t.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 

 FREQUENCY IN KILOCYCLES PER SECOND 



Fig. 7. — Attenuation versus frequency characteristics of bandpass filters shown at 

 (b) in figure 5. 



1.0 t.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 

 FREQUENCY IN KILOCYCLES PER SECOND 



Fig. 8. — Linear discriminator characteristic. 



