| 摘要 |
PURPOSE:To perform correct decoding regardless of the inversion of the pulse polarity of a transmission medium by generating a control signal indicating whether or not the polarity is inverted on a transmission line according to which of a 1st and a 2nd discriminators attain discrimination. CONSTITUTION:A switching controller 9 detects whether or not the pulse polarity is inverted on the transmission line including a cable 10 according to from which of the discriminators 3 and 4 the pulses in the time slot of a frame timing signal arrives, right after the convergence of an equalizer 2. The connection state of a polarity switch 5 is so set that when there is no inversion (or inversion) 1 the sent pulse train of the discriminator 3 (or 4) is led to the positive polarity pulse input terminal of e decoder 6 and the sent pulse train of the discriminator 4 (or 3) is led to the negative polarity pulse input terminal of the decoder 6. Then, the training and frame synchronization of the equalizer 2 are performed 4 in a training period and the inversion of the pulse polarity on the transmission line is detected, when there is the inversion, the polarity is inverted again by the polarity switch 5. |
