JPH01165233A - Optical repeater - Google Patents

Abstract

PURPOSE:To prevent a code from being sent erroneously at the time of performing the automatic switching of a circuit from a light transmission circuit in current use to a spare light transmission circuit by delaying a switching signal by providing a delay circuit between a control circuit and the light transmission circuit in current use, and simultaneously, fitting a phase from the light transmission circuit in current use in that of the spare light transmission circuit to be inputted to a photocoupler. CONSTITUTION:The control circuit 5 outputs the switching signal (c) to turn 'OFF' the light transmission circuit in current use to the delay circuit 6 at a time T1. Since the delay circuit 6 outputs the switching signal (c) to the light transmission circuit 2 in current use after attaching a delay time T3(T3>T2), the light transmission circuit 2 in current use is turned 'OFF' at a time T4, then, a signal (i) is outputted to the photocoupler 4. To the photocoupler 4, a signal (j) from the spare light transmission circuit 3 and the signal (i) from the light transmission circuit 2 in current use are inputted, and the phases of those signals are fitted in by electrical signals 21 and 23, or optical signals 22 and 24. In such a way, even when the light transmission circuit in current use and the spare light transmission circuit are driven simultaneously, the codes are only superposed, and sent to the output of a transmission path correctly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical repeater, and more particularly to an optical repeater equipped with a working optical transmission circuit and a standby optical transmission circuit.

[Conventional technology]

An example of this type of optical repeater is shown in FIG. In FIG. 2, an optical signal from a transmission line 11 is received by an optical receiving circuit 1 and converted into an electrical signal. The working optical transmitting circuit 2 converts the electrical signal from the optical receiving circuit 1 into an optical signal and outputs the optical signal. This optical signal is output to the transmission line 12 via the optical coupler 4.

By the way, when the working optical transmitter circuit 2 deteriorates, the deterioration information a
is output to the control circuit 5. Based on this deterioration information a, the control circuit 5 sends a switching signal C to the working optical transmitting circuit 2 to turn the working optical transmitting circuit 2 "off", and turns the standby optical transmitting circuit 3 "off".
A switching signal "on" is sent to the backup optical transmitter circuit 3. In response to the switching signal, the backup optical transmitter circuit 3 converts the electrical signal from the optical receiver circuit 1 into an optical signal and outputs it. , are output to the transmission line 12 via the optical coupler 4.

In this way, an optical repeater having a working optical transmission circuit and a backup optical transmission circuit has a function of automatically switching to the backup optical transmission circuit when the working optical transmission circuit deteriorates.

[Problem that the invention seeks to solve]

In the above-described conventional optical repeater, a code error occurs in the line during the switching operation when the working optical transmitting circuit 2 is automatically switched to the backup optical transmitting circuit 3. For example, when the optical receiver circuit l of the optical repeater is receiving the signal e as shown in FIG. As shown in FIG. 4, the circuit 2 turns "off" at time TI and outputs the signal ". However, the backup optical transmitter circuit 3 does not turn "on" immediately even if the switching signal is input. As shown in FIG. 4, it becomes "on" after time T2 and outputs the signal g.The optical coupler 4 outputs the signal shown in FIG. 4 using these signals f and g. However, during time T2,
There is a drawback that no code is output, and during this time a code error occurs on the line, and it is impossible to determine whether it is a code error in the repeater or a code error due to automatic switching.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks and to provide an optical repeater that does not generate code errors even when switching from a working optical transmitter circuit to a standby optical transmitter circuit by automatic switching.

[Means for solving problems]

The present invention includes an optical receiving circuit that receives an optical signal from a transmission path and converts the optical signal into an electrical signal, and an optical receiving circuit that receives an optical signal from the optical receiving circuit via a working electrical signal path. The working optical transmitter circuit converts the signal into an optical signal and outputs it, outputs deterioration information when it deteriorates, and turns ``off'' when the working switching signal is input, and turns ``on'' when the backup switching signal is input. The electrical signal from the optical receiving circuit is input via the backup electrical signal path, and the backup optical transmitting circuit converts the electrical signal into an optical signal and outputs it, and the deterioration information from the working optical transmitting circuit, a control circuit that outputs a working switching signal to the backup optical transmission circuit; a delay circuit that delays the working switching signal from the control circuit and outputs it to the working optical transmission circuit; An optical coupling in which an optical signal from a transmitting circuit is inputted via a working optical signal path, an optical signal from the backup optical transmitting circuit is inputted via a backup optical signal path, and these two optical signals are combined and output. The phase of the optical signal from the working optical signal path and the phase of the optical signal from the backup optical signal path, which are input to the optical coupler, are input to the optical coupler. It is characterized by being more compatible with the signal path, the working optical signal path, and the standby optical signal path.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In this embodiment, the same components as those of the optical repeater shown in FIG. 2 are denoted by the same numbers.

This optical repeater includes an optical receiving circuit 1, a working optical transmitting circuit 2, a backup optical transmitting circuit 3, an optical coupler 4, a control circuit 5,
It is composed of a delay circuit 6.

In the optical repeater having such a configuration, the optical receiving circuit 1 includes:
It receives an optical signal from the transmission line 11, converts this optical signal into an electrical signal, and outputs the electrical signal.

The working optical transmitting circuit 2 receives an electrical signal from the optical receiving circuit 1 via an electrical signal path 21, converts the electrical signal into an optical signal, and outputs the optical signal. The working optical transmitting circuit 2 outputs deterioration information a to the control circuit 5 when it deteriorates. Moreover, when the working optical transmitting circuit 2 receives the switching signal from the delay circuit 6, it turns "off".

When the backup optical transmission circuit 3 receives the switching signal from the control circuit 5, it turns on, but it does not turn on immediately, but turns on later. When turned on, the backup optical transmitter circuit 3 receives an electrical signal from the optical receiver circuit 1 via the electrical signal path 23, converts this electrical signal into an optical signal, and outputs the optical signal.

When the control circuit 5 receives the deterioration information a from the working optical transmitter circuit 2, it sends a switching signal C that turns the working optical transmitter circuit 2 "off" to the delay circuit 6, and turns the backup optical transmitter circuit 3 "on". ” is sent to the standby optical transmitter circuit 3.

The delay circuit 6 delays the switching signal C from the control circuit 5 by a predetermined time and outputs the delayed signal to the working optical transmitter circuit 2 .

The optical coupler 4 connects the working optical transmitter circuit 2. Optical signals from the backup optical transmission circuit 3 are received via optical signal paths 22 and 24, and these optical signals are combined and output to the transmission path 12.

Next, the operation of this embodiment will be explained with reference to the time chart of FIG.

The optical signal C from the transmission line 11 is received by the optical receiving circuit 1 and converted into an electrical signal. The working optical transmitting circuit 2 receives the electrical signal from the optical receiving circuit 1 via the electrical signal path 21 and converts it into an optical signal. The optical coupler 4 includes an optical signal path 22
Upon receiving the optical signal from the working optical transmission circuit 2 via the optical transmission circuit 2, the optical signal is output to the transmission line 12.

By the way, when the working optical transmitter circuit 2 deteriorates, the control circuit 5
Deterioration information a is sent to the
OFF”, automatic control to turn on the backup optical transmitter circuit 3,
In other words, automatic switching is performed. This kind of automatic switching
For example, when performed at time T1 shown in FIG.
The signal is output to the standby optical transmitter circuit 3. Spare optical transmitter circuit 3
It takes time T2 for the signal j to turn from "off" to "on", and the backup optical transmitter circuit 3 turns "on" at time T, and outputs the signal j to the optical coupler 4.

At the same time, at time T, the control circuit 5 outputs to the delay circuit 6 a switching signal C that turns off the working optical transmitter circuit 2.

The delay circuit 6 provides the switching signal C with a delay time T:+(Tz>
Tz) and outputs it to the working optical transmitter circuit 2, so
The working optical transmitter circuit 2 turns "off" at time T4 and outputs the signal i to the optical coupler 4.

The signal j from the backup optical transmission circuit 3 and the signal i from the working optical transmission circuit 2 are input to the optical coupler 4, but the phase of these signals 1+J is determined by the electrical signal path 2L 23 or the optical signal. Match at road 22.24. That is, the sum of the lengths of the current electrical signal path 21 and the current optical signal path 22 is made to be the sum of the lengths of the backup electrical signal path 23 and the backup optical signal path 24. In this way, when the in-phase signals it J are input, the optical coupler 4 combines these signals i and j and outputs the signal k to the transmission line 12.

In this way, in this embodiment, the working optical transmitting circuit is turned "off" after the backup optical transmitting circuit is turned "on", and by matching the phase of the optical coupling weak input, the working and backup optical transmitting circuits can be simultaneously activated. Even when the signals are being driven, the codes simply overlap and are sent to the transmission line output without error.

〔Effect of the invention〕

As explained above, the present invention provides a delay circuit between the control circuit and the working optical transmitter circuit to delay the switching signal, and at the same time aligns the phases of the signals from the working optical transmitter circuit and the standby optical transmitter circuit that are input to the optical coupler. This has the effect that the code can be transmitted without error when automatically switching from the working optical transmitting circuit to the backup optical transmitting circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing an example of a conventional optical repeater, and FIG. 3 is a time chart of the optical repeater shown in FIG. 1. , FIG. 4 is a time chart of the optical repeater shown in FIG. 2. 1... Optical receiving circuit 2... Working optical transmitting circuit 3... Backup optical transmitting circuit 4... Optical coupler 5... Control circuit 6... Delay circuit Agent Patent attorney Yoshiyuki Iwasa Figure 1 Figure 2

Claims (1)

[Claims] (1) An optical receiving circuit that receives an optical signal from a transmission line and converts the optical signal into an electrical signal; and an optical receiving circuit that receives an optical signal from the optical receiving circuit via a working electrical signal line and converts the electrical signal into an electrical signal. Convert it to an optical signal and output it,
A working optical transmitter circuit that outputs deterioration information when it deteriorates and turns "off" when a working switching signal is input, and a working optical transmitting circuit that turns "on" when a backup switching signal is input and receives an electrical signal from the optical receiving circuit. is inputted via a backup electrical signal path, and a backup optical transmission circuit converts this electrical signal into an optical signal and outputs it, and a backup optical transmission circuit outputs a working switching signal based on the deterioration information from the working optical transmission circuit and outputs a working switching signal to convert the electrical signal into an optical signal and output it. a control circuit that outputs a preliminary switching signal to a transmission circuit; a delay circuit that delays a working switching signal from the control circuit and outputs it to the working optical transmitting circuit; an optical signal from the working optical transmitting circuit is a working optical signal; an optical coupler that receives an optical signal from the backup optical transmission circuit via the backup optical signal path, and combines and outputs the two optical signals; The phase of the optical signal from the working optical signal path and the phase of the optical signal from the backup optical signal path, which are input to the working electrical signal path, the backup electrical signal path, the working optical signal path, and the backup optical signal path, are An optical repeater that is characterized by its ability to better match the signal path.