JPH01173936A - Optical communication equipment - Google Patents

Abstract

PURPOSE:To establish an optical communication path and to easily alarm the fault of transmission in communicating by always monitoring a fixed bit pattern signal at a reception side with transmission data from a transmission side. CONSTITUTION:A reception circuit 9 always monitors the fixed bit pattern signal FLM inputted at every constant cycle. And in the case of receiving the signal FLM periodically, the reception of the data is permitted, and in the case of receiving an erroneous fixed bit pattern signal FLM due to the fault of a transmission path, etc., the reception of the data is interrupted, and at a time when the next fixed bit pattern signal is received correctly, the reception of the data is restarted. Also, state transition by a state transition device in the reception circuit 9 is reported to a state display circuit 10, and the state display circuit 10 reports a transition state being set by a display lamp or a buzzer, etc., to an operator corresponding to the transition state. In such a way, the operator can recognize the fault of the transmission in a state where an optical transmission path is established easily not only at the time of starting optical communication.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical communication device, and particularly to an optical communication device that performs optical communication through the atmosphere.

[Conventional technology]

Generally, an optical communication device consists of an optical transmitting circuit section and an optical receiving circuit section. For example, as described in Japanese Patent Laid-Open No. 59-47854, the optical receiving circuit section receives a carrier pulse signal from the optical transmitting circuit section. Accordingly, the optical communication is performed after confirming the establishment of the optical transmission path.

(Problems to be Solved by the Invention) Although the above-mentioned conventional technology takes into account the establishment of an optical transmission line, even if the optical transmission line is established, due to malfunction of the circuit, correct transmission and reception of optical signals may not be possible. If this is not the case, a problem arises in that it is not possible to warn the operator that this communication cannot be performed properly.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical communication device that can not only establish an optical transmission line during optical communication but also notify an operator whether or not it is in a state where normal data exchange can be performed.

[Means for solving problems]

To achieve the above object, the present invention provides an optical communication device comprising an optical transmitter and an optical receiver, in which the optical transmitter adds a bit pattern signal with a predetermined cycle to a predetermined position of a transmitted electrical signal. a detection means for detecting the bit pattern signal from the received electrical signal; and a monitoring means for monitoring whether the bit pattern signal detected by the detection means has a predetermined cycle; A warning means is provided for issuing a warning if the bit pattern signal is found to be inconsistent with a predetermined period based on the result of monitoring by the monitoring means.

[Effect]

The warning means warns the operator that normal data exchange cannot be performed if the bit pattern signal in the received optical signal does not have a predetermined period.

Therefore, the operator can know that even if the optical transmission path is established, data cannot be sent and received normally.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing an optical communication device according to this embodiment, FIG. 2 is a diagram showing details of the receiving circuit in FIG. 1, and FIG. 3 is a diagram for explaining the operation of the device shown in FIG. 1. FIG. 4 is a diagram for explaining the state transition of the state transition circuit.

The optical communication device shown in FIG. 1 includes an optical transmitter 1 and an optical receiver 2.
The optical transmitting section 1 includes a bit pattern generating circuit 5 that generates a predetermined constant bit pattern signal FLM, a data transmitting circuit 4 that generates transmission data, and the bit pattern generating circuit 5 or the data transmitting circuit 5. A timing circuit 3 that prompts the circuit 4 to generate a bit pattern signal or data signal, a switching circuit 6 that switches and outputs the bit pattern signal FLM or data signal according to instructions from the timing circuit 3, and an input from the switching circuit 6. and an optical transmission circuit 7 that converts the signal received into an optical signal and outputs the optical signal. The optical receiver 2 includes a light receiving circuit 8 that receives the optical signal 20 from the optical transmitting circuit 7 and converts it photoelectrically, and a receiving circuit that uses the electrical signal input from the light receiving circuit 8 to determine whether or not the device is capable of communication. The receiving circuit 9 includes a circuit 9 and a status display circuit 10 for notifying the operator of the determination result of the receiving circuit 9.

Details of the receiving circuit 9 are shown in FIG. This circuit consists of a clock regenerator 11 that creates a basic clock from a photoelectrically converted received signal, a serial/parallel converter 12 that converts the received signal into parallel data based on the clock, and a bit pattern in this parallel data. A bit pattern detector 13 that identifies whether the signal FLM is included and outputs a detection signal C when the pattern signal FLM is included, and a temporal position at which the detection signal C and a time-up signal d to be described later are generated. and a period comparator 15 that compares and outputs a comparison result (match or mismatch), a standby mode preset by the detection signal C, and a time-up signal d generated by itself.
A period monitoring timer 14 having a self-running mode that repeats self-running, a mode switch 16 that switches the mode according to signals C and d, and comparison results from the bit pattern detection signal C and the period comparator 15. a state transition device 18 which takes as an input, displays the state of the device and outputs a communication enable signal e when communication is possible, and the communication enable signal e.
is provided with a received data output device 17 that outputs the received data when the received data is output.

As shown in FIG. 4, the states classified by the state transition device 18 are an initial state A immediately after the power is turned on, a protection state B in which the bit pattern signal FLM is detected, and a detection signal C of the bit pattern and the period monitoring timer. This is a synchronization state C in which data transmission is permitted when the period matches that of the time-up signal d from 14. Further, the time charts of the respective signals shown in FIGS. 1 and 2 have the relationships shown in FIG. 3.

Hereinafter, the operation of this embodiment will be explained by dividing it into a plurality of sections A to N with reference to the time chart and map shown in FIG.

First, the optical communication device shown in FIG.
The bit pattern generation circuit 5 generates the bit pattern signal FLM in accordance with the timing sent from the FLM, outputs the transmission signal a to the optical transmission circuit 7 via the switching circuit 6, and then the data transmission circuit 4 generates the data signal. and switching circuit 6
is output to the optical transmission circuit 7 by switching. The generation of the pattern signal FLM and the data signal is performed periodically with a period of time T.

The optical transmission circuit 7 converts the previously inputted transmission signal a into an optical signal and supplies it to the light receiving circuit 8 of the receiving section 2 via the optical transmission line 20. The light receiving circuit 8 inputs a received signal obtained by photoelectrically converting the received optical signal to the receiving circuit 9. The operation of this receiving circuit 9 will be explained using FIGS. 2 and 3.

First, a received signal inputted to the receiving circuit 9 is regenerated into a basic clock by a clock reproducing circuit 11, and is converted into a basic clock by a serial/parallel converter 12 based on this clock.

Converted to parallel data. This parallel data is identified by the bit pattern detector 13 as to whether or not there is a bit pattern signal FLM, and when the signal FLM is detected, time 1 in FIG.
．． The detection signal C is output at the timing. By this detection signal C, the cycle monitoring timer 14 via the mode switch 16 is set to a free running mode that outputs a time-up signal d every cycle T, and the state transition machine 18 is changed from the initial state A in FIG. Switched to protection state B. Next, at time 2, the time-up signal d triggered by the detection signal C at time t1 and the FLM detection signal C at 1 time t2 are input to the period comparator 15 in synchronization, so that the comparator 15 outputs a signal OK indicating that the periods of these signals C and d match. In response to this OK signal, the state transition circuit 18 shifts its state to the synchronous state C, and at the same time outputs a data signal via the received data output device 17 in response to the communication enable signal e.

In this state C, the bit pattern signal FLM which is input alternately with the data signal is detected by the bit pattern detector 13.
The period comparator 15 continues to output the signal OK, and the reception of the data signal continues.

Now, if the bit pattern signal FLM output from the transmitter 1 is garbled into an abnormal bit pattern signal FLM' in the received signal due to a failure in the communication optical path between times t3 and t4, Since the pattern detector 13 does not output the detection signal C, the period comparator 15 outputs the signal NG. As a result, the state transition device 18 returns the synchronization state C to the protection state B, interrupts the communication enable signal e, and suspends data reception.
Correct bit pattern signal FLM at next time t5
is input and the detection signal C is output, the cycle is matched with the time-up signal d, so the cycle comparator 15 outputs the signal OK again, and the state transition device 18 changes the protection state B to the synchronization state C. to resume receiving data signals.

Further, if the data signal D' input from time t8 to t9 happens to have the same pattern as the bit pattern signal FLM, the bit pattern detector 13 outputs the detection signal C at time t9, but the timing up signal d Since the period comparator 15 outputs a signal NG, the synchronization state C is returned to the protection state B, and data reception is interrupted. At the same time, the cycle monitoring timer 14 is released from the self-running mode and is moved to the standby mode. That is, the mode is set to wait for the input of the detection signal C. Next, when the detection signal C of the pattern signal FLM is detected at time tlo, the cycle monitoring timer 14 returns to the free running mode, and the time-up signal d matches the next detection signal C, and the cycle is compared. The device 15 outputs a signal OK.

As a result, the state transition device 18 returns the protection state B to the synchronization state C and starts receiving data signals again.

In this way, the receiving circuit 9 according to the present embodiment monitors the bit pattern signal FLM input at regular intervals, and
Data reception is allowed if the LM is correct, data reception is interrupted if the signal FLM is incorrect due to a transmission failure, etc., and data reception is resumed if the next bit pattern (No. B FLM is correctly received).

Further, each state by the state transition device 18 is reported to the state display circuit lO shown in FIG.
Each of the above states is reported to the operator using an indicator light or a buzzer. This allows the operator to easily know transmission failures not only at the start of optical communication but also when the optical transmission path is established.

〔Effect of the invention〕

As described above, according to the present invention, in order to transmit and monitor a pattern signal for optical path monitoring along with transmission data,
It is possible to easily warn of transmission failures during establishment of an optical communication path and communication.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the optical communication device according to the present invention, FIG. 2 is a diagram showing the circuit configuration of the receiving circuit in FIG. 1, and FIG.
The figure is a flowchart mainly for explaining the operation of the circuit shown in FIG. 2, and FIG. 4 is a diagram for explaining each state transition of the receiving circuit according to the present embodiment. DESCRIPTION OF SYMBOLS 1... Transmission circuit, 2... Receiving circuit, 3... Timing circuit, 4... Data transmitting circuit, 5... Bit pattern generation circuit, 6... Switching circuit, 7... Light Transmitting circuit, 8... Light receiving circuit, 9... Receiving circuit, 10...
Status display circuit, 11... Clock regenerator, 12... Serial-to-parallel converter, 13... Bit pattern detector, 14...
...Period monitoring timer, 15...Period comparator, 16...
・Mode switcher, 17... Reception data output device, 18・
...State transition machine. Patent applicant Hitachi Communication Systems Co., Ltd. Representative Patent Attorney Masami Akimoto (1 other person) Procedure Mh ■ Masami (voluntary) March 28, 1988

Claims (1)

[Claims] 1. An optical transmitter that converts an electrical signal into an optical signal and outputs it;
an optical receiver that receives the optical signal and reconverts it into an electrical signal, and has an optical propagation space between the optical transmitter and the optical receiver, wherein the optical transmitter has a It includes an adding means for adding a bit pattern signal of a predetermined period to a predetermined position of the electric signal, and after the optical receiver converts the optical signal received through the optical propagation space into an electric signal, the electric signal is added to the electric signal. a detection means for detecting the bit pattern signal from a signal; a monitoring means for monitoring whether the bit pattern signal detected by the detection means has a predetermined cycle; 1. An optical communication device comprising: warning means for issuing a warning when the period is not set.