| 摘要 |
PURPOSE:To enable to perform the preequalization for temperature change and time aging change simply, by separately detecting the temperature and time aging variances in transmission line loss, and transmitting the detected information with the level difference of two pilot signals adjacent in the frequencies. CONSTITUTION:When a temperature loss variance of transmission line is present between the time again preequalizer 17 and the temperature preequalizer 21 of the terminal station 13, the temperature detection pilot PLP1 having the frequency negligible in time aging variance is inserted. The temperature detection PL level detector 34 of the terminal station 14 detects the loss temperature variance with the signal P1, and this output controls the temperature post-equalizer 25, temperature preequalizer 22 and temperature information transmitter 35. The transmitter 35 transmits the output of the detector 34 at the level difference of the close frequencies PLP21 and P22, and this signal controls the equalizer 21 and temperature post equalizer 26 via the temperature information receiver 37. Further, the time aging detector PLP2 inserted at the terminal station 14 is detected at the time aging detection PL level detector 38 to control the time aging post equalizer 28, equalizer 17 and time aging information oscillator 39. The oscillator transmits the close frequencies P12, P11 and this level difference controls the time aging equalizers 27, 18. |
