JPS5616337A - Monitor system for delay amount of transmission line - Google Patents

Abstract

PURPOSE:To secure an accurate monitor for the delay amount of the transmission line with a simple method, by transmitting the pilot pulse having a longer repetitive period than the folded propagation delay time of the transmission line and then measuring the delay time during which the pilot pulse is floded along the transmission line and then fed back. CONSTITUTION:The clock pulse sent from the main oscillating circuit is divided into 1/n through dividing circuit 12 to be turned into pilot pulse (g). The period of pulse (g) is set longer than the folded propagation delay time of the transmission line. The output of circuit 12 is supplied to frame pulse generating circuit 13 as well as pseudo signal generating circuit 14, and the outputs of circuits 13 and 14 are converted into bipolar signals (e) through OR circuit 15 and unipolar-bipolar converting circuit 16 to be delivered. Signal (f) which is folded along the transmission line and then fed back receives extraction of the clock signal via bipolar-unipolar converting circuit 20, frame pulse detecting circuit 21 and synchronizing circuit 22 each. This clock signal is then divided into 1/n through dividing circuit 23 to generate pilot pulse (h). Both pulses (g) and (h) are supplied to pulse interval measuring circuit 26 for measurement of the delay amount of the transmission line. Thus an accurate monitor is possible for the delay amount of the transmssion line.