602 



BELL SYSTEM TECHNICAL JOURNAL 



large number of such cable circuits in terms of certain functions of the 

 capacitance and inductance deviations. From this paper the dis- 

 tribution function of the return losses may be expressed in decibels 

 as follows: 



S — Sh -]r Sw ~ Sa -\r Sp = Si -\- Sf 

 (See Appendix VI for Nomenclature). 



In this equation Sf is the distribution function of the return losses and 

 Si is the return loss at the frequency in question which is exceeded by 



10 20 30 40 50 60 70 80 90 lOO 



PER CENT OF CASES HAVING LOWER RETURN LOSSES OR MARGINS 



Fig. 2 — Values of Sp and Sf- 



