Theoretical Fundamentals of Pulse 

 Transmission — TI 



By E. D. SUNDE 



(Manuscript received September 23, 1953) 



Part II. 



12. Impulse Characteristics and Pulse Train Envelopes 987 



13. Transmission Limitations in S3'mmetrical Systems 991 



14. Transmission Limitations in Asymmetrical Sideband Sj^stems 996 



15. Double vs. Vestigial Sideband Systems , 1004 



16. Limitation on Channel Capacity by Characteristic Distortion 1007 



Acknowledgements 1010 



References 1010 



Part I of this paper dealt with various idealized transmission characteris- 

 tics and with methods of evaluating pulse distortion resulting from various 

 system imperfections. In Part II the resultant transmission impairments or 

 limitations on pidse transmission rates are discussed for systems with low- 

 pass, symmetrical hand-pass and asymmetrical hand-pass characteristics, 

 and a comparison made of the transmission performance of double and 

 vestigial sideband systems. The limitation on channel capacity imposed by 

 random imperfections in the transmission-frequency characteristic, as com- 

 pared to random noise, is also discussed. 



12. IMPULSE CHARACTERISTICS AND PULSE TRAIN ENVELOPES 



In pulse modulation systems pulses are transmitted in various com- 

 binations to form pulse trains, and at the receiving end the envelope of 

 the pulse train is sampled at regular intervals to determine the ampli- 

 tudes of the transmitted pulses. As a result of pulse overlaps there may 

 be appreciable distortion of the pulse train envelope, which may cause 

 errors in reception or noise, depending on the type of system. To evalu- 

 ate transmission impairments, or limitations imposed on transmission 

 capacity to avoid excessive transmission impairments from pulse dis- 

 tortion, it is necessary to establish basic relations between the impulse 

 characteristic of the system and the envelope of the received pulse train. 



In Fig. 42 are shown three transmitted pulses of different peak ampU- 

 tudes, A-i , Ao and Ai , transmitted at intervals r with the first and third 



987 



