| 摘要 |
PURPOSE:To detect the abnormal condition of a signal on a transmission line with a simple hardware by initializing a timer each time a detecting means detects the starting of the signal and deciding that a trouble occurs when a timer informs of the progress of a constant time specified based on the open- loop delaying time of the transmission line and the maximum length of the signal. CONSTITUTION:An SD detecting device 14 detects a starting delimiter SD of a bucket to pass on a transmission line 6. A timer 15 is the one to measure the progress of a constant time specified by the open-loop delaying time and the maximum bucket length of the transmission line 6and starts to measure the initialized time progress by an SD detecting output from the SD detecting part 14. Consequently, at the time of the normal action, the timer 15 is initialized by the SD detecting part 14 before the set time is measured and an output 15-1 of the SD detecting part will not come to be an activated condition. When the detecting interval of the starting delimiter SD exceeds the maximum value of the interval of the usual SD detection, the timer 15 makes the output 15-1 into the activated condition and informs a transmitting part 16 that the abnormality occurs.
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