| 摘要 |
PURPOSE:To prevent missing of data by sending 2 kinds of signals in the case of sending a data and replacing the data in other signal if the data is missing in any of the two signals. CONSTITUTION:If any missing part takes place in an optical signal 8', a dropout detector 16 outputs a low level L, and in this case, a terminal B of a changeover switch 19 is connected to the position of a terminal C, then a normal PCM signal is outputted. Since the delay of a ROM signal 18' being an output of a demodulator 13 and that of a PCM signal 17'' via a delay memory 14 are the same at that time, the phase of the signals is identical. Thus, even if a received data is missing through the passing of an obstacle on one transmission line, the missing is compensated by using the data on the other transmission line. |
