JPS5957536A - System for monitoring intermediate repeater - Google Patents

Abstract

PURPOSE:To detect a failure of a pilot level, by interrupting a signal coupled to a repeater in opposite direction at a failure of the pilot level so as to locate a failed point in a land coaxial cable line system having no spare line. CONSTITUTION:A control amplifier amplifies selectively the pilot signal at an intrmediate repeater station 1 provided between monitor stations 2, 3, and suppose that a failure in the pilot level is detected. If a repeater in the direction of E-W is failed in this case, an SV-OSC signal coupled to a repeater in the direction of W-E at the transmission side is interrupted with a diode switch, and if the repeater in the W-E direction is failed, the SV-OSC signal coupled to the repeater in the E-W direction is interrupted. The SV-OSC signal and the OSC signal are monitored respectively at receiving side monitor stations 3 and 2 so as to attain the location of a failed point. The failure is detected at the transmission side at a failure of the pilot level, the SV-OSC signal is detected at the receiving side and the shift in the pilot level is recognized.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method for monitoring intermediate repeaters in a coaxial cable line system.

(2) Prior art and problems There are several conventional methods for monitoring intermediate repeaters in coaxial line systems.One example is a method for displaying pilot-level abnormalities without using an intervening pair. FIG. 1 shows a circuit in which the fault detection current oscillator (SV-O3C) signal is turned off. In the monitoring system shown in FIG. 1, both the E-W and 'W-E repeaters and the 5v-osc are installed in the same case 1. s, v
-osc is supplied with power by dividing a part of the power supply current to the repeater in the E-W direction. The signal of Sv-0SC is distributed and coupled by hybrid H to repeaters in both directions of EW, , and W-E. Of course, E, -W.

It is also possible to provide 5V-O20 for each W-E (-fi, but the cost will increase accordingly. In this case, βV-
o The SC signal is coupled to each repeater without being distributed. In each control amplifier, all selected pyro-soto signals sent from the monitoring station are amplified, and when the pilot level is abnormal, the 17icU guide switch etc.
-Turn off the osc signal.

At the monitoring station on the receiving side, SV-〇S from each repeater
C signal (different frequencies are assigned to each repeater)
By monitoring the operating status of individual repeaters and pilot level abnormalities.

By the way, in the repeater monitoring system shown in Fig. 1, when a large number of P-AGC repeaters are used in the intermediate repeater as in the all-overhead system, if the line becomes overloaded due to a repeater failure, υ5V-O8C There is a possibility that it will not be possible to locate the fault point using the signal. 5 even if the failure point can be located.
Since the v-osc signal is disconnected, there is a problem in that it is not possible to detect to what extent the pilot level is abnormal.

Conventionally, in order to prevent the above problem, a method has been considered in which a pilot level abnormality in one system is detected and the 5V-OSC of the other system is stopped in a system having a backup line (see Fig. 2). The disadvantage is that a backup line is required.

(3) Purpose of the Invention In view of the problems of the conventional type described above, the purpose of the present invention is to provide a land coaxial cable line system without a backup line.
By cutting off the 5V-O8C signal coupled to the repeater in the opposite direction when the pilot level is abnormal, it is possible to not only locate the fault point but also detect the extent of the pilot level abnormality. Possible intermediate repeater monitoring method J&:
It is about providing.

(4) Structure of the Invention In the present invention, a fault-search current oscillator is provided, and the output of the oscillator is coupled to each of the nine upward and downward repeaters and transmitted together with a signal to a monitoring station, and the monitoring station searches for a fault. In the intermediate repeater monitoring method that selectively receives current and monitors the operating status of the intermediate repeater, each uplink and downlink repeater is equipped with a pilot signal detection circuit to detect abnormalities in the pilot signal of the uplink repeater. The pilot signal An intermediate repeater monitoring system is provided in which monitoring B1 is performed at the transmitting side monitoring station via a repeater in the opposite direction of all abnormalities.

(5) Embodiment of the Invention An intermediate repeater monitoring system according to the present invention is shown in FIG. In the monitoring system shown in Figure 3, when a pilot signal is selectively amplified by a control amplifier and an abnormality in the pilot level is detected, if the E-W direction repeater is abnormal, the opposite W-E direction repeater is used. The 5V-O8C signal coupled to the device is cut off by diode switch V, and if the repeater in the W-E direction is abnormal, the s v connected to the repeater in the E-W direction is
-Turn off the osc signal. That is, the driving wiring of the diode switch is reversed from that in FIG. 1.

With the configuration shown in FIG. 3, the monitoring of the 5V-OSC signal, that is, the monitoring of the transmission level of each intermediate relay point based on the readiness level of the S'V-OSC signal, is carried out by the receiving side monitoring station 3 as in the conventional case. In addition, in the event of a repeater fault, the fault point can be located by receiving the 5V-O8C signal at the transmitting side monitoring station 2 via the repeater in the opposite direction. Furthermore, in the case of an abnormality at the pilot level,
Since it is possible to detect abnormalities on the transmitting side and monitor the 5V-OSC signal on the receiving side, for example, if a pilot alarm is designed to have a standard level of ±2 dB, it is possible to check how much the level deviates from the standard level when an alarm occurs. It can be seen whether an alarm is occurring (for example, whether it is -3 dB or -20 dB from the standard level), which is very effective from the point of view of maintenance.

FIG. 4 shows 5v-O8C in the monitoring system according to the present invention.
One configuration of circuitry for coupling signals to each repeater is shown. In Fig. 4, diode switches DSI, D
Drive signals from each control amplifier are connected to S2. There is a difference in the power supply potential between the E-W and W-E direction p repeaters, but in the land 11TL cable line system, the power supply potential is different between the E-W and W-E direction p repeaters. The voltage is not that high (1.5-2.0 kV
), general voltage-resistant capacitors C1, C2, O3,
It is sufficient to insert C4 as shown in FIG. In addition, in Fig. 4, one SV"O20 has E-W, W-
Although it is distributed in both E directions, a similar configuration can be made in the case where 5V-O20 is provided in each of E-W and -V-B directions.

(6) Effects of the Invention According to the present invention, it is possible to provide an intermediate repeater monitoring system that can locate a failure point using a simple circuit and can detect the degree of level abnormality when the pilot level is abnormal.

[Brief explanation of drawings]

Fig. 1 is a diagram showing a conventional intermediate repeater monitoring system, Fig. 2 is a diagram showing the intermediate repeater monitoring method when a backup line is provided, and Fig. 3 is a diagram showing an intermediate repeater monitoring system according to the present invention. FIG. 4 is a diagram showing a circuit for coupling the 5V-O8C signal to each repeater in the monitoring system of FIG. 3. (Explanation of symbols) 1: Intermediate repeater, 2.3: Monitoring station. Patent applicant Fujitsu Ltd. Patent agent Akira Ikuki Patent attorney Nishidate No. 11 Patent attorneys 1) Yukio Patent attorney Yama 1] Akiyuki Figure 1 Figure 2

Claims (1)

[Claims] Equipped with a fault search current oscillator, the output of the oscillator is coupled to each uplink and downlink repeater and transmitted together with a signal to a monitoring station.The monitoring station selectively receives the fault search current and determines the operating status of the intermediate repeater. In the intermediate repeater monitoring method, each uplink and downlink repeater is equipped with a pilot signal detection circuit, and when the uplink repeater's pilot signal is abnormal, the fault detection current coupled to the downlink repeater is detected. Definitely,
When there is an abnormality in the pilot signal of the downstream repeater, the abnormality in the pilot signal can be monitored by the transmitting monitoring station via the repeater in the opposite direction by cutting off the fault detection current coupled to the upstream repeater. An intermediate repeater monitoring method that has been made possible.