CARRIER TELEGRAPH METHODS 



517 



band frequency-shift arrangements are thought to be no worse than the 

 normal-band frequency-shift arrangement from this standpoint, because of 

 the greater separation between the sidebands of the adjacent channels. 

 According to a study of the frequency spectra produced by abrupt or sinusoi- 



Table IV 



1998-CycLE Single-Sideband Arrangement (No Spacing Carrier), Effect of 



Operating .\dtacent 1828-Cycle and 2168-Cycle Single-Sideband 



Channels over Line 



Table V 

 1998- Cycle Single-Sideband Arrangement (With Spacing Carrier 6 db Below 

 Marking Carrier), Effect of Operating Adjacent 1828-Cycle and 

 2168-Cycle Single -Sideband Channels over Line 



Table VI 



1955±35-Cycle Freqltency-Shift Arrangement (With Relay Modulator), Effect 



OF Operating Adjacent 1785 ± 35-Cycle and 2125 ± 35-Cycle 



Frequency-Shift Channels over Line 



dal frequency-shift arrangements during transmission of reversals^, it 

 appears that the sinusoidal shift is better than abrupt shift from the stand- 

 point of interference between adjacent channels, when the sending channel 

 filter does not sufficiently attenuate undesired sideband components. But 



'^Balth. van der Pol: "Frequency Modulation", Proc. I. R. E., Vol. 18, No. 7, July 

 1930, pp. 1194-1205. 



