Telephone influence factor. for a voltage or current wave in an electric supply circuit, the ratio of the square root of the sum of the squares of the weighted root-mean-square values of all the sine wave components to the root-mean-square value (nonweighted) of the entire wave.
A measure of the inductive effect exerted by a power system on nearby telephone circuits, represented by the noise level in the telephone receiver.
Telephone Influence Factor. The higher harmonics in the voltage wave shape of a generator can cause undesirable effects on telephone communications when power lines parallel telephone lines. The telephone influence factor is calculated by squaring the weighted RMS values of the fundamental and the non-triple series of harmonics, adding them together and then taking the square root of the sum. The ratio of this value to the RMS value of the no-load voltage wave is called the Balanced TIF. The ratio of this value to three times the RMS value of the no-load phase-to-neutral voltage is called the Residual Component RIF.