THEORETICAL FI'XDAMENTAES OF IM'LSE THA XSMISSION 



747 



This expression is zero when sin 2coo<o — sin wo4 = 0, and also when 

 cos oooio/2 = 0. Zero points in the impulse characteristic will occur at 

 uniform intervals to = x/wo = l/^/o • Pulses can accordingly be trans- 

 mitted at these intervals without mutual interference, or at the same 

 rate as for a low-pass characteristic with the bandwidth to the half- 

 amplitude point equal to coo • This is the same pulse transmissioii rate 

 as is possible in principle with an ideal band-pass characteristic as shown 



BAND-PASS CHARACTERISTIC 

 y SHOWN IN FIG. 9 



OJq Wm li^i = 2 a>o 

 FREQUENCY, 00 *- 



(a) AMPLITUDE VS FREQUENCY CHARACTERISTIC 



\ ^-ENVELOPE P(t) 



(b) IMPULSE CHARACTERISTIC 



Fig. 1.5 — Particular case of band-pass characteristic with tiradual cut-off in 



which inij^ulse characteristic is zero at intervals ro = 



2/0 



