| 摘要 |
PURPOSE:To judge the polarity of a subscriber line with simple constitution by detecting the frame synchronizing signal of a binary code data with either the polarity on one side of complementary data, and using the polarity of data at a side detecting all 1s or 0s. CONSTITUTION:A code conversion part 1 outputs the complementary data RD+ and RD- by converting a received quaternary code to a binary code. A synchronizing signal detecting part 2 detects the frame synchronizing signal by using, for example, the data RD+ out of them. Pattern detecting parts 3 and 4 detect whether or not the data RD+ and RD- from the conversion part 1 show prescribed all 1s or 0s synchronizing with the detection of the frame synchronizing signal. A selector 5 selects and outputs the data with the polarity on one side of the data RD+ or RD- with the detecting output of the detecting parts 3 and 4 as reception data RD. |
