Certain Factors Limiting the Volume Efficiency of Repeatered Telephone Circuits

HE excellence of transmission over a toll telephone circuit is determined by its overall volume efficiency (including the effect of variations from time to time), by distortion of the waves, by various delay effects and by the masking effect of noise. The term " n e t loss" 1 is commonly used to more specifically designate the overall volume efficiency as limited by the factors which will be discussed herein. It is equal to the total loss introduced by the toll lines and all associated apparatus minus the total gain introduced by all of the amplifiers. In the United States the net loss is usually given for the single frequency of 1,000 cycles and is expressed in decibels.