292 



BELL SYSTEM TECHNICAL JOURNAL 



z 



UJ 10 



to -10 

 < 



CO 



-20 

 -30 

 -40 



-40 -30 -20 -10 10 20 30 40 



MARK-TO-SPACE LEVEL RATIO IN DECIBELS 



Fig. 32. — Signal bias versus mark-to-space level ratio in FS transmission — 740-cycle 

 band, 350-cycle frequency shift. 



Q. -5 



z 



o) -10 



< 



CO 

 -15 



-20 



-25 



-30 



-35 



-35 -30 



•25 -20 -15 -10 -5 5 10 15 20 



MARK-TO-SPACE LEVEL RATIO IN DECIBELS 



25 



Fig. 33.— Signal bias versus mark-to-space level ratio in FS transmission— 80-cycle 

 cutoff low-pass filter. 



at the moment when the frequency changes. In Fig. 33 this bias effect is 

 demonstrated for various bandwidths. For moderate mark-to-space level 

 ratios the bias effect is small and linear, with a slope which usually varies 



