Bell system and International telecommunications noise-measuring systems

This paper provides an analysis of the Bell System noise units, the International Telephone and Telegraph Consultative Committee (CCITT) noise units, and their absolute power and interfering relationship. Clear and concise definitions of the terms used by each are included. The weighting curves of each system, based on 1,000 cycles for the Bell System and 800 cycles for the CCITT, are included for clear explanation of the noise equivalence between the two systems and to enable engineers to convert miscellaneous tones to weighted decibel-adjusted (dba) values. Some examples in the use of Table I for the solution of noise problems within the scope of these two systems are included.