| 摘要 |
PURPOSE:To reduce the distortion occurring at each repeater as well as the intelligible crosstalk caused by the cross modulation distortion for the long-distance carrier system, by adding the line pilot current applied with the frequency modulation. CONSTITUTION:It is supposed that eout=a0 + a1Xein + a2<2>Xein<2> + a3<3>X ein<3> + ... is delivered when ein=Acosalpha + Bcosbeta + Ccosgamma is supplied. In this case, the AM modulation is applied to frequencies alpha and beta with no modulation applied to gamma. Thus the mutual modulation distortion component and the cross modulation distortion component may possively be the intelligible crosstalk. As a result, the intelligible crosstalk can be prevented by applying the modulation to the gamma frequency supposed to be applied with no modulation. At the same time, the power component is dispersed to the modulation bands from the single frequency by applying the modulation to the line pilot current 2-2, thus increasing the distortion reduction effect. |
