COAXIAL CABLE SYSTEM FOR TELEVISION TRANSMISSION 453 



Carrier Supply 



Another important feature of this system was the provision of 

 accurately spaced carriers for the various modulating operations. The 

 Bell System 4 kc. standard was used to produce a 72 kc. (18th har- 

 monic) base frequency signal which could be transmitted over the line 



Fig. 13 — Photograph of the transmitting carrier television terminal with associated 



sound apparatus. 



and so tie the transmitting and receiving ends together. From this, 

 by harmonic generation, the carriers used in the two steps of modu- 

 lation were produced, being the 33rd and 35th harmonics. 



To synchronize the scanning at the receiving end with the trans- 

 mitting disk required another direct tie. The disk is driven by a d-c. 



