JPH05145533A - Transmission network subordinate synchronization system - Google Patents

Abstract

PURPOSE:To attain changeover control into a reference phase signal from other subordinate destination normally when a fault takes place in a selected reference phase signal. CONSTITUTION:Phase comparison sections 12, 13 compare a phase of an N- system of a reference phase signal and a phase of an N-system phase synchronizing signal with a predetermined threshold level and send monitor result signals a, b to a control section 19. Phase comparison sections 14, 15 compare a phase of a reference phase signal of E system and a phase of a phase synchronizing signal of the E system with a predetermined threshold level and send monitor result signals c, d to the control section 19. The control section 19 judges it that the reference phase signal of the N system is not normal when the monitor result signals a, b are at the threshold level or over and the monitor result signals c, d are within the threshold level and sends a switching signal (f) to a selection section 10, which selects the reference phase signal of the E system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a digital transmission network, and when an abnormality occurs in a selected reference phase signal,
The present invention relates to a transmission network slave synchronization method for selecting a reference phase signal from another slave.

[0002]

2. Description of the Related Art FIG. 2 shows a configuration of a conventional transmission network slave synchronization system.

In FIG. 1, stations A, B and C are
A redundant configuration is provided, and as shown in the detailed configuration of the B station, the selecting section 1 to which the transmission line from the A station or the like is connected, and the input section of the transmission line are detected to switch the selecting section 1. The input signal disconnection detection unit 2 is provided.

Further, the phase synchronization unit 3 which is connected to the selection unit 1 and includes a phase synchronization signal oscillator, the phase synchronization unit 4, the control unit 5, and the selection unit 6 for selecting the phase synchronization unit 3 or the phase synchronization unit 4. And are provided.

Next, the operation of this configuration will be described.

The received reference phase signal is selected by the selector 1 by the switching signal from the input signal disconnection detection circuit 2. Then, by comparing the phase with the reference phase signal from the selection unit 1, the control unit 5 monitors the abnormality of the phase synchronization signal oscillator provided in the phase synchronization units 3 and 4. The control unit 5 causes the selection unit 6 to select the output phase signal of the normal phase synchronization signal oscillator of the phase synchronization units 3 and 4.

[0007]

However, in the transmission network dependent synchronization method of the conventional example, for example, when the transmission path between the A station and the B station is disconnected as shown in FIG. 3, the phase synchronization of the B station is synchronized. The free-running phase signal from the phase synchronization signal oscillator provided in the units 3 and 4 is used as the reference phase signal in the phase synchronization unit in the dependent station C to perform the phase synchronization processing.

In this case, when the phase synchronization signal oscillator of the B station is out of phase due to a failure or the like, the dependent station C outputs a phase synchronization signal different from the predetermined reference phase signal from the phase synchronization signal oscillator. However, there is a drawback that the synchronization with the subordinate station C is lost.

An object of the present invention is to solve such a problem, and in the case where an abnormality occurs in the selected reference phase signal, it is possible to normally perform the switching control to the reference phase signal from another dependent destination. It is to provide a synchronization method.

[0010]

According to the transmission network slave synchronization system of the present invention, a selecting means for outputting a selected reference phase signal selected from a plurality of supplied reference phase signals and an input selected reference phase signal, A plurality of phase synchronization signal oscillating means for oscillating respectively synchronized phase synchronization signals, a plurality of reference phase signals, and a plurality of phase synchronization signals are input, and a monitoring result signal compared with a preset threshold value is transmitted. A plurality of phase comparison means and a plurality of monitoring result signals are supplied,
The judging means for judging whether the selection reference phase signal is normal or abnormal, and when the judging means judges that the selection reference phase signal is abnormal, the selecting means judges the reference phase signals from other subordinates. And a selection control means for performing selection control.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a transmission network dependent synchronization system of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of the embodiment. In FIG. 1, this example shows the reference phase signals (MC) of N system and E system.
LK (N), (E)) is supplied to the selection unit 10, N-system reference phase signals (M-CLK (N)) are supplied to the phase comparison units 12 and 13, and E-system reference phase signal is supplied. (M-CLK
(E)) is supplied to the phase comparison units 14 and 15, and the phase synchronization circuit units 16 and 17 connected to the output terminals of the selection unit 10 are provided.

Further, the output end of the phase synchronization circuit unit 16 is connected to the phase comparison units 12 and 13, and the output end of the phase synchronization circuit unit 17 is connected to the phase comparison units 14 and 15.

In addition, these phase comparators 12, 13, 1
Output terminals 4 and 15 are connected, and a control unit 19 for switching the selection unit 10 is provided.

Next, the operation of this configuration will be described.

The selection unit 10 normally selects the N-system reference phase signal (M-CLK (N)) to select the phase-locked loop circuit unit 16.
To the reference phase signal (M-CLK
(N)) to perform phase synchronization based on the reference phase signal CLK
(N) is output.

Reference phase signal of N system (M-CLK (N))
And the phase synchronization signal (C
LK (N)) is supplied to the phase comparison units 12 and 13. In the phase comparators 12 and 13, the N-system reference phase signal (M
-CLK (N)) and the N-system phase synchronization signal (CLK
The phase of (N)) is compared with a predetermined threshold value, and the monitoring result signal a and the monitoring result signal b are sent to the control unit 19.

The E-system reference phase signal (M-CLK
(E)) and the phase synchronization signal (CLK (E)) from the E-system phase synchronization circuit unit 17 are supplied to the phase comparison units 14 and 15. In the phase comparators 14 and 15, the E-system reference phase signal (M-CLK (E)) and the E-system phase synchronization signal (C
The phase of LK (E)) is compared with a predetermined threshold value, and the monitoring result signal c and the monitoring result signal d thereof are sent to the control unit 19.

In the control unit 19 to which the monitoring result signals a, b, c, d are supplied, the monitoring result signal a and the monitoring result signal b are equal to or more than the threshold value, and the monitoring result signal c and the monitoring result signal d are the threshold value. If it is within the range, the N phase reference phase signal (MC)
It is determined that LK (N)) is abnormal. Based on this determination, the switching signal f is sent to the selection unit 10. With this switching signal f, the selection unit 10 selects the E-system reference phase signal (M-CLK (E)), and the phase synchronization circuit unit 17 outputs CLK (E).

In this way, when an abnormality occurs in the selected N-system reference phase signal (M-CLK (N)), switching to the E-system reference phase signal (M-CLK (E)) is performed. Control is performed normally.

[0021]

As is apparent from the above description, the transmission network dependent synchronization system of the present invention selects a plurality of reference phase signals and a plurality of phase synchronization signals by a monitoring result signal which is compared with a preset threshold value. When it is determined that the reference phase signal has an abnormality, the reference phase signal from another slave is selected. This has the effect that the switching control to the reference phase signal from the beginning can be performed normally.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration in an embodiment of a transmission network dependent synchronization system of the present invention.

FIG. 2 is a block diagram showing a configuration in a slave synchronization system of a conventional example.

FIG. 3 is a block diagram showing a configuration of a transmission network used for explaining an operation of a conventional example.

[Explanation of symbols]

 10 selection unit 12, 13, 14, 15 phase comparison unit 16, 17 phase synchronization circuit unit 19 control unit a, b, c, d monitoring result signal f switching signal

Claims (1)

[Claims] 1. A selection means for outputting a selected reference phase signal selected from a plurality of supplied reference phase signals, and a plurality of phase synchronization devices for oscillating a phase synchronization signal respectively synchronized with the input selected reference phase signal. Signal oscillating means, a plurality of reference phase signals, a plurality of phase synchronization signals are input, a plurality of phase comparing means for sending a monitoring result signal respectively compared with a preset threshold, and the plurality of monitoring results A signal is supplied to the selection reference phase signal to determine whether the selection reference phase signal is normal or abnormal, and the selection means determines that the selection reference phase signal is abnormal. A transmission network subordination synchronization method comprising a selection control means for performing control for selecting a reference phase signal from another subordinate.