THE N-1 CARRIER SYSTEM 



17 



channel circuits. At the input of the transmitting circuit, the output of the 

 compressor LPF and the signal keyer are connected. At the output all 



1 + 130 V 



MODULATOR 

 UNBALANCING 



CIRCUIT <r MODULATOR 



VOICE FREQUENCY 



FROM TRANSMITTING 



LOW- PASS FILTER 



COMBINING 

 MULTIPLE 



v/^frvvv 



FROM KEYER CIRCUIT 

 (3700'^) 



+130 V 



TO TRSG 

 GROUP UNIT 



VOICE 



FREQUENCY 



TO RECEIVING 



LOW- PASS FILTER 



AND SIGNALING 



3700^^ 

 BAND-PASS FILTER 



(b) 



OUTPUT CHANNEL 



DEMODU- TRANS- REGULATOR 

 LATOR FORMER 



INPUT CHANNEL 

 LEVEL BAND-PASS 

 CONTROL FILTER 



' — VW 



CARRIER FREQUENCY 



FROM 



RECEIVING GROUP 



CIRCUIT 



Fig. 7(a) — Channel carrier frequency transmitting circuit, 

 (b) — Channel carrier frequency receiving circuit. 



modulators are connected together through pads individual to each channel 

 and mounted on the terminal frame. The crystal oscillator uses a pentode 

 tube arranged as a triode oscillator with electron coupling to the plate for 



