DELAY TIME MEASURING DEVICE FOR TRANSMISSION LINE

PURPOSE:To measure the amount of delay of a transmission line, by transmitting signals from one station with disturbed rule of codes, disturbing the transmission signals from the other station to the one station in receiving the signals having disturbed rule of codes, and detecting the going and returning time of the signals having disturbed rule of codes at the one station. CONSTITUTION:A bipolar signal from a multiplexing and separating device 1 is transmitted after the rule of code is changed by one bit at code rule changing circuit 3 with a signal from a delay time amount measuring device 2. The disturbance of the rule of codes is detected at a code rule detection circuit 5. The output of the circuit 5 is applied to a code rule changing circuit 6 to change the rule of code of the bipolar code from a multiplexing and separating device 7 by one bit. The going and returning time of a digital transmission line is detected from the difference between the code rule changing time at a code rule detecting circuit 4 and an output time to the circuit 3, thereby measuring the delay time value.