650 BELL SYSTEM TECHNICAL JOURNAL 



of the type described above, the antenna current, or the transmitted 

 wave, may be represented diagrammatically as shown in Fig. 9. 



SPEECH SIGNALS 

 (50-5000~) 



TELEVISION SIGNALS 

 (l0-20000~) 



20 



INPUT TO RADIO TRANSMITTER 

 / 10-20000— \ 

 ^2 5000-35000-/ 



3^q^^^-SUPPLEMENTARY CARRIER (SOOOO-^) 



OUTPUT OF RADIO TRANSMITTER 



/I540-I550 KC\ 



1555-1595 KC 



\I600-I6I0 KCy 

 1545 



RADIO 



CARRIER 1605 



>k: 



1540 1550 1555 1575 1595 1600 1610 



Fig. 9 — Diagrammatical representation of frequency conversions in multiplex 



radio system 



It is evident that this type of radio signal can be received by em- 

 ploying an arrangement which will accept the entire band and subject 

 it to rectification in the usual manner. If this is done, the television 

 signal and the 30,000-cycle supplementary carrier modulated with 

 speech will appear at the output of the detector. Branch circuits with 

 suitable filters will enable these two components to be separated and 

 the television signal passed on to the reproducing apparatus. The 



