TIIEOKETICAL FUNDAMENTALS OF I'ULSE TUANSMISSIOX //5 



PULSE TRAIN ENVELOPE ZERO LINE WITH LOW-FREQUENCY CUTOFF 



"ZERO LINE WITHOUT LOW-FREQUENCY CUTOFF 



^/__ ^X^ Y^ X A-. 



I J_r 1 , PULSE TRAIN ENVELOPE AND ZERO LINE 



n 2 I / WITH LOW-FREQUENCY CUTOFF 



?~v 7~N f"'^ /~N 7~s /•"% 



/ \ / \ -' \ / \ / \ / 



/^ > / / /^ 

 / / \ / \ / \ / \ / ^ ' ZERO LINE WITHOUT 



/ / \ / \ / \ / \ / \ y LOW-FREQUENCY CUTOFF 



^1 ^1 S^<. s^<? N*.*? >w^ \ / r 



Fig. 33 — Effect of low-frequency cut-off on recurrent pulses as pulse interval 

 is decreased. 



If it is assumed that positive and negative impulses are applied at 

 random to the transmission systems at intervals n , the rms intersymbol 

 interference resulting from a low-frequency cut-off can be evaluated by 

 essentially the same method as employed in Section 8 for fine structure 

 imperfections in the transmission characteristic, provided wo is much 

 smaller than oji . On this basis, rms intersymbol interference in relation 

 to the peak amplitude Po(0) of the pulses in the absence of a low-fre- 

 quency cut-off becomes: 



For a transmission characteristic with linear phase shift 



Po(0) = - f AM Jco. (9.05) 



TT Jo 



