998 



THE BELL SYSTEM TECHNICAL JOURNAL, JULY 1954 



With double sideband transmission, pulses would be transmitted at 

 the points m = 0, ±2, ±4, etc. At these points the quadrature com- 

 ponents vanish, as indicated in the above figure, and the in-phase com- 

 ponents are the same in amplitude as with double sideband transmission. 

 Thus, if pulses were transmitted at the same rate as with double side- 

 band transmission, the sum of the absolute values of the in-phase com- 

 ponents at the sampling points would be identical with the sum of the 

 absolute values of the envelope with double sideband transmission. It 

 follows from the criteria established in Section 13 that for this particular 

 pulse transmission rate the effect of pulse distortion would be the same 

 with both transmission methods. With an ideal transmission frequency 



TRANSMISSION 



FREQUENCY 



CHARACTERISTIC 



P(t) = ENVELOPE OF IMPULSE CHARACTERISTIC 



R = IN-PHASE COMPONENTS AT SAMPLING INSTANTS 



Q = QUADRATURE COMPONENTS AT SAMPLING INSTANTS 



r = 1/0)3 = PULSE INTERVALS WITH DOUBLE SIDE BAND TRANSMISSION 



Fig. 46 — In-phase and quadrature components of impulse characteristic with 

 vestigial side-band transmission. 



