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BELL SYSTEM TECHNICAL JOURNAL 



case, when the n pulses are equally spaced, they are 360° apart at c and 

 consequently 360° + 36 or 396° at c + v. Therefore in the unmodulated 

 case, each component would be advanced in phase 36° with respect to the 

 previous one, so that the diagram of the 10 components would form the 



FREQUENCY C+V 



(a) ZERO MODULATION 

 10 



(b) 50 PER CENT MODULATION 

 10 



FREQUENCY C-V 



(C) ZERO MODULATION 



(d) 50 PER CENT MODULATION 

 9 8 10 2 I 



Fig. 7 — Vector pattern of subsidiary pulse components. 



vector pattern shown on Fig. 7A. The successive components are numbered 

 1 to 10. The sum in this unmodulated case is of course zero. 



Now the effect of modulation is to shift the relative jjhascs of these compo- 

 nents by an amount determined by the shift in position of the corresponding 

 pulses. When these relative phase shifts are such as to spoil the can- 



