Attenuation in a telephone circuit loaded with coils having non-linear characteristics

Formulaelig are given by which, when the attenuation per unit length is a quadratic function of current, it is possible to calculate the overall attenuation of a line for various current strengths rigorously or, alternatively, to estimate in a simple way the limits between which the correct value lies. Certain discrepances in other published formulaelig are pointed out. The importance of using the correct attenuation formula, rather than an approximate one, is stressed, even in cases where the approximate formula gives a tolerably correct value of attenuation. It is pointed out that when the hysteresis attenuation is measured by a device which reads the voltage or current ratio rather than the power ratio, it is necessary to make an impedance correction which is comparable with the hysteresis attenuation. The results of calculations and measurements are in substantial agreement.