JPH1022921A - Optical communication device - Google Patents

Abstract

(57) [Problem] In a conventional optical communication device, when a failure or deterioration occurs in a device, a receiving side distinguishes between a deterioration of an optical transmitter or an optical fiber and a failure or deterioration at a stage preceding them. Was difficult to attach. SOLUTION: An optical transmitter side 100 is provided with a transmission monitoring timer circuit 15 which does not continuously output a signal for a predetermined time t or more, and a receiving side 101 sets a duration of a carrier 12 of a received signal. A carrier monitoring timer circuit 16 for monitoring and outputting a signal 17 when this continues for more than t, and a storage and holding circuit 18 for storing this signal 17
And provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method for enabling a receiving side to judge deterioration of an optical transmitting side or an optical transmission line when an optical transmission system is used for communication between electronic devices.

[0002]

2. Description of the Related Art Various electronic devices are connected by signal lines.
2. Description of the Related Art There is an optical communication device that exchanges data and command signals in one direction or each other, and uses an optical signal as a transmission medium. FIG. 7 is a functional block diagram showing a conventional optical communication device similar to the optical communication device disclosed in Japanese Patent Application Laid-Open No. 3-191626. In the figure, reference numeral 99 denotes a signal source that outputs a signal 3 to be transmitted (hereinafter also referred to as a transmission signal) and a transmission permission signal 2 indicating a transmission timing, and 1 encodes the transmission signal 3 when the transmission permission signal 2 is significant. The encoder 5 that outputs the transmission signal 4 is a transistor that amplifies the power of the transmission signal 4 and obtains the drive signal 6 of the optical transmitter 7. Reference numeral 81 denotes a monitoring pulse generator that generates a monitoring pulse signal every predetermined time. A pulse detection circuit 82 detects a monitoring pulse.

[0003] Reference numeral 7 denotes an optical transmitter for performing an electrical-to-optical conversion, 8 denotes an optical fiber for relaying an optical signal, 9 denotes an optical receiver that performs an optical-to-electrical conversion and outputs a signal 10, and 11 denotes a communication signal from the signal A carrier detection circuit which detects the presence / absence of the signal and makes the output signal 12 significant if there is a signal, and a decoding circuit 13 which decodes the signal 10 and outputs a reception output signal 14. In addition, the light transmitter 7 is set to a lighting state (a state of emitting light) in a state where no communication is performed. Reference numeral 100 denotes a transmission-side electronic device (hereinafter, referred to as a transmission side), and 101 denotes a reception-side electronic device (hereinafter, referred to as a reception side). Further, the signal source 99 here includes a transmission line connecting the signal source 99 and the transmission side 100.

Next, the operation will be described. Optical transmitter 7
Is the transmission signal 4 encoded by the encoder 1 when the transmission permission signal 2 transmitted from the signal source 99 is significant.
Is driven by the transistor 5 to transmit an optical signal. The optical signal transmitted through the optical fiber 8 is input to an optical receiver 9, and the optical receiver 9 outputs an electric signal 10 corresponding to the turning on / off of the optical signal. When the carrier detection circuit 11 to which the signal 10 has been input determines that there is a communication signal, the output signal 12 is made significant, indicating that there is a signal to be processed in a subsequent circuit (not shown). Also, the decoding circuit 13
Decodes the signal 10 and passes the received output signal 14 restored to the signal 3 before being input to the encoder 1 on the transmission side to the subsequent stage (not shown). The monitoring pulse generator 81 and the pulse detector 82 are respectively provided at predetermined time intervals, for example, two times.
The communication is started once every four hours after the original communication is interrupted. Then, a predetermined (pulse interval or pulse number) pulse signal is transmitted, and by confirming that the received signal is a predetermined signal, it is confirmed that the communication state is normal.

[0005] In the optical communication device thus configured, the transmitting side 100 is often installed at a long distance from the receiving side 101. Therefore, if there is a failure in the optical communication operation during this time, for those who are on the receiving side,
Determining whether the fault is in the intermediate optical fiber 8, the transmitter 100, or earlier, ie, in the signal source 99, is extremely important in resolving the fault and repairing the optical communication. It is. However, FIG.
When the signal source 99, the transmitting side 100, and the optical fiber 8 are connected in series as in the above, no matter what part of the failure occurs, the failure appears in the received signal output 14 in the same manner. The determination is difficult.

Further, the monitoring performed by the monitoring pulse generation circuit 81 and the pulse detector 82 has disadvantages such as that the communication must be temporarily interrupted and that monitoring is not performed during normal communication.

[0007]

Since the conventional optical communication apparatus is configured in series as described above, the transmission error and the signal source due to the deterioration of the optical transmitter or the optical fiber (before the optical transmitter) There is a problem in that it is not possible to distinguish the transmission error generated in the above, and when an abnormality is detected, it is necessary to investigate all the transmission lines including the optical communication device.

Further, the method using the monitoring pulse and the monitoring pulse detector has a problem that monitoring cannot be performed during normal communication.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is intended for an optical transmitter or a transmission error due to deterioration of an optical fiber and another place on a transmission line (before the optical transmitter). An object of the present invention is to provide an optical communication device capable of distinguishing a transmission error that has occurred and performing monitoring during ordinary communication, and further achieving this object without significantly changing the conventional device. With the goal.

[0010]

An optical communication apparatus according to a first aspect of the present invention includes a transmission monitoring timer circuit provided on a transmission side for preventing a transmission signal from being continuously transmitted for a predetermined time or more, and a transmission monitoring timer circuit for a reception side. A carrier monitoring timer circuit that outputs a signal when a received signal is continuously received for the predetermined time or more, and a storage holding circuit that stores the signal output by the carrier monitoring timer circuit. It is.

An optical communication apparatus according to a second aspect of the present invention is a code transition rule violation detection circuit for detecting a code transition rule violation of a received signal, and counts the number of detections output by the code transition rule violation detection circuit. It has a violation number counting circuit that outputs a signal when the value exceeds a preset value.

An optical communication device according to a third aspect of the present invention includes a transmission monitoring timer circuit provided on a transmission side for not continuously transmitting a transmission signal for a predetermined time or more, and receiving an output of the transmission monitoring timer circuit. Then, after the output of the transmission monitoring timer circuit stops, it turns on after T1 time,
A timing generation circuit for outputting a signal to be turned off after a time T2 after this on, an output level adjusting means for adjusting the output level of the optical transmitter to a predetermined level, and a receiving side for detecting the presence or absence of a received signal. A carrier detection circuit, a timing signal generation circuit that outputs a timing signal having a predetermined time width T6 at a predetermined timing T5 based on an output of the carrier detection circuit, and a reception signal generation unit that outputs a reception signal while the output of the timing signal is significant. A code transition rule violation detection circuit that detects a code transition rule violation, a violation count circuit that counts the number of detections output by the code transition rule violation detection circuit, and outputs a signal when the number exceeds a preset value. It has.

An optical communication apparatus according to a fourth aspect of the present invention turns on and off the optical transmitter at a speed three times or more as fast as the on / off speed of the signal pulse while continuously outputting the optical output. It has a blinking signal generation circuit capable of adjusting the time ratio to off.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 15 denotes a transmission monitoring timer circuit for preventing continuous transmission for a predetermined transmission time (t) or more, and 16 denotes a transmission monitoring timer circuit when the carrier presence state continues for a predetermined time (t) or more. Carrier monitoring timer circuit which makes output signal 17 of
If the signal 17 becomes significant even once, its output signal 19
A gate that outputs the signal 12 as it is when the signal 19 is not significant, and a gate that makes the output signal 21 insignificant regardless of the signal 12 when the signal 19 is significant; A lamp 22 is turned on when the signal 19 is significant. Here, the time t is a short time in, for example, seconds.

FIG. 2 is an operation timing chart of the circuit of FIG. 1, in which the horizontal lines indicate time. And the amount of light received by the optical receiver 9,
Output signal 10 of optical receiver 9, output signal 12 of carrier detection circuit 11, output signal 1 of carrier monitoring timer circuit 16.
7, the output signal 19 of the storage circuit 18 and the output signal 21 of the gate 20 are shown over time. The horizontal line 23 is the minimum value of the amount of received light that can be recognized when the light transmitter 7 is turned on, and the horizontal line 24 is the maximum value of the amount of received light that can be recognized that the light transmitter 7 is turned off. The left half of FIG. 2 illustrates an example in which all the devices have no abnormality, and the right half of FIG. 2 illustrates an example in which the optical transmitter 7 or the optical fiber 8 has an abnormality.

Referring to FIG. 2, a case in which all devices have no abnormality will be described. The system is designed so that the amount of light received by the optical receiver 9 is equal to or greater than the value of the horizontal line 23 when the optical transmitter 7 is on, and equal to or less than the value of the horizontal line 24 when the optical transmitter 7 is off. When the optical transmitter 7 transmits the signal from the point of time to the point of time 26, the output signal 1 of the optical receiver 9
0 is correctly output according to the light receiving pattern, and the signal 12 is also significant from time 25 to time 26. If the time during which the signal 12 is significant is slightly shorter than the set time t of the carrier monitoring timer circuit 16, the signal 17 is not significant, the signal 19 is not significant, and the lamp 22 is not turned on. Therefore, the signal 21 becomes the same as the signal 12, and a subsequent circuit (not shown) can detect that the signal 21 is significant and process the reception output signal 14.

Referring to FIG. 2, a case where the optical transmitter 7 or the optical fiber 8 has deteriorated or failed (hereinafter referred to as deterioration) will be described. After time 27 (right side of the figure)
When the amount of light received by the optical receiver 9 becomes a value between the horizontal lines 23 and 24 due to deterioration, the signal 10 becomes undefined. Here, "indefinite" means that the level is not determined, and the level fluctuates between the upper and lower sides, or remains unbalanced to one or the other.

In the case where the carrier is still shifted to one side, the carrier detection circuit 11 can easily detect that there is no carrier. If the level fluctuates, the carrier detection circuit 11 incorrectly recognizes that the carrier is present and makes the signal 12 significant in the worst case because the signal 10 is unstable. However, since the significant time of the signal 12 is not necessarily shorter than the set time t of the carrier monitoring timer circuit 16, the time set at the carrier monitoring timer circuit 16 at time 28 becomes the output signal 1
7 becomes significant, the output signal 19 of the storage circuit 18 is held significantly, and the lamp 22 is turned on to indicate the detection of deterioration.
Further, since the output signal 21 of the gate 20 is made insignificant by the signal 19, the subsequent circuit can detect that the signal 21 is not significant and stop the processing of the meaningless received output signal 14. . Since the time t is extremely short, it means that the monitoring is continuously performed during the normal communication. Needless to say, the storage circuit 18 can erase the storage by a reset signal (not shown).

Embodiment 2 In order to detect the reception of the deteriorated optical signal, an abnormality of the output signal 10 of the optical receiver 9 may be detected. In FIG. 3, reference numeral 29 denotes a code transition rule violation detection circuit for the signal 10, and reference numeral 30 denotes a violation count circuit.

Next, the operation will be described. The sign transition rule violation detecting circuit 29 detects a sign transition rule violation of the signal 10 when the signal 12 is significant.
1 is significant. The violation count circuit 30 counts the number of times that the signal 31 is significant, and when the count is equal to or greater than a set value,
The signal 19 is made significant, the signal 21 is made insignificant, and the lamp 22 is turned on. Thus, by adding a circuit to the receiving side 101, it is possible to detect that the optical transmitter 7 or the optical fiber 8 is deteriorated.

Embodiment 3 By adding a circuit to the transmission side 100, the detection accuracy can be further improved.
In FIG. 4, 32 indicates signal 4 only when signal 33 is significant.
, A timing generation circuit that generates a timing signal 35 from the signal 33, a transistor 36 that controls the output of the optical transmitter 7 to a set light amount,
Is a resistor for setting the transmission light amount of the optical transmitter 7, and 38 is a timing signal generation circuit for generating a timing signal 39 and a signal 40 from the signal 12.

FIG. 5 is a timing chart showing the operation of the circuit shown in FIG.
5, the output signal 35 of the timing generation circuit 34, the amount of light received by the optical receiver 9 and its output signal 10, the output signal 12 of the carrier detection circuit 11, the output signal 39 and the signal 40 of the timing signal generation circuit 38, Number detection circuit 30
Output signal 19 and signal 21 are shown over time.

The operation will be described with reference to FIG. Signal 3
3 changes in the same manner as the transmission permission signal 2 as long as the transmission permission signal 2 does not continue to be significant due to a device failure or the like. The signal 35 generated by the timing generation circuit 34 is a signal that becomes significant after the time T1 from the fall 41 of the signal 33 and becomes insignificant after the time T2.

The resistance 37 indicates that the amount of light received by the optical receiver 9 is equal to that of the horizontal line 23 while the optical transmitter 7 or the optical fiber 8 is not degraded and the timing generator 34 outputs the signal 35.
Is set to be slightly larger than the value of. That is, the current of the optical transmitter 7 is limited by using the resistor 37 and the transistor 36 in order to reduce the amount of light transmitted from the optical transmitter 7 when the timing generation circuit 34 is outputting. The resistor 37 is an output level adjusting means of the optical transmitter 7.

The signal 39 generated by the timing signal generating circuit 38 becomes insignificant after T3 time from the falling edge 42 of the signal 12, and becomes significant after T4 time. The signal 40 generated by the timing signal generation circuit 38 is based on the falling edge 42 of the signal 12 as the signal 3.
Similar to 5, the signal becomes significant after T5 hours and becomes insignificant after T6 hours. However, it is necessary to satisfy the following condition. T3 <T1 <T5, T6 <T2 <T4

The code transition rule violation detection circuit 29 performs an operation of detecting a code transition rule violation of the signal 10 only while the output signal 40 of the timing signal generation circuit 38 is significant. The state where the optical transmitter 7 or the optical fiber 8 has not deteriorated from the time 43 to the time 44 is shown. Here, the amount of light received by the optical receiver 9 is always in a region where it can be correctly determined. Since the output signal 10 of 9 is output correctly according to the light receiving pattern, no transmission error is detected on the receiving side 101.

From time 45 to time 46, a state in which the optical transmitter 7 or the optical fiber 8 is deteriorated is shown. Here, the amount of light received by the optical receiver 9 during the period 47 in which the signal 35 is significant is shown. Enters the undeterminable range of the horizontal line 24 from the horizontal line 23, so that the output signal 10 of the optical receiver 9 becomes an incorrect signal,
A transmission error is detected in a period 48 during which the signal 40 is significant, and the signal 19 becomes significant at, for example, a timing 49.
At this time, the carrier signal 12 is falsely output as significant, but since the signal 39 is 50 during the insignificant period,
The signal 21 does not become significant, and the subsequent circuit erroneously outputs the signal 14
Will not be processed.

In the example shown in FIG. 4, the signal current supplied to the optical transmitter is adjusted as a means for reducing the amount of light of the optical transmitter 7. However, this means is effective for a type having no internal buffer, It is only an optical transmitter whose light quantity changes according to the magnitude of the current.

Embodiment 4 As means for reducing the amount of light transmitted by the optical transmitter 7, blinking is repeated at a sufficiently high speed (three times or more high) as compared with the on / off speed as a signal, for example, so fast that the operation of the optical receiver 9 cannot catch up. Is also good. In FIG. 6, reference numeral 51 denotes a blinking signal generation circuit which can output a high-speed on / off signal 52 in which a ratio of a significant time to a non-significant time can be arbitrarily set, and 53 designates a signal 52 when the output 35 of the timing generation circuit 34 is significant. The gate 55 is used as its own output signal 54, and 55 is a gate for synthesizing the signals 54 and 56.

In the example shown in FIG. 6, since the light amount can be adjusted only by turning on / off the signal current supplied to the optical transmitter 7, the type having a buffer inside, that is, the light amount can be controlled by the magnitude of the signal 6. The effect of reducing the apparent output light amount can be obtained even for the optical transmitter 7 that does not have the optical transmitter 7.

[0031]

According to the first aspect of the present invention, the carrier monitoring timer circuit does not output when the signal source fails, but outputs only when the optical transmitter or the optical fiber is deteriorated. Faults and signal source faults can be distinguished. The transmission path can be monitored even during normal communication.

According to the second aspect of the present invention, the transmission monitoring timer circuit for limiting the signal transmission time to a predetermined length or less and the circuit for detecting a code transition rule violation of the carrier of the received signal are provided. It is possible to distinguish between a fault on the transmission line and a fault in the signal source.

According to the third invention, the transmission monitoring timer circuit, the timing generation circuit and the output level adjusting means are provided on the transmission side, and the carrier detection circuit, the timing generation circuit, the code transition rule violation detection circuit and the violation are provided on the reception side. The provision of the number counting circuit makes it possible to distinguish between a fault on the transmission line and a fault at the signal source.

According to the fourth aspect, the applicable range of the present invention can be broadened.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an optical communication device according to a first embodiment of the present invention.

FIG. 2 is an operation timing chart of the block diagram of FIG. 1;

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing Embodiment 3 of the present invention.

FIG. 5 is an operation timing chart of the block diagram of FIG. 4;

FIG. 6 is a functional block diagram showing a fourth embodiment of the present invention.

FIG. 7 is a functional block diagram showing a conventional optical communication device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Encoder, 2 Transmission permission signal 3 Signal to be transmitted 7 Optical transmitter, 8
Optical fiber, 9 optical receiver, 11
Carrier detection circuit, 13 decoding circuit, 1
5 transmission monitoring timer circuit, 16 carrier monitoring timer circuit, 18 memory holding circuit, 23
Optical signal detection minimum level, 24 Optical signal non-detection maximum level, 29 Code transition rule violation detection circuit, 30 times detection circuit, 34 timing generation circuit, 3
7 resistance, 38 timing signal generation circuit, 51 blinking signal generation circuit, 99
Signal source, 100 transmitting side, 101
Receiver

Claims (4)

[Claims] 1. An optical communication device for performing communication by optical transmission between a transmitting side and a receiving side via an optical fiber cable or a space, wherein a signal to be transmitted provided on the transmitting side is predetermined. A transmission monitoring timer circuit that does not continuously transmit for more than a time, a carrier monitoring timer circuit that is provided on the receiving side and outputs a signal when a received signal is continuously received for a predetermined time or more, An optical communication device comprising: a storage holding circuit that stores the signal output by the monitoring timer circuit. 2. A code transition rule violation detection circuit for detecting a code transition rule violation of a received signal instead of a carrier monitoring timer circuit, and measuring a code transition rule violation detection number output by the code transition rule violation detection circuit. And a violation count circuit that outputs a signal when the number of times of detection is equal to or greater than a preset value, and the memory holding circuit stores a signal output by the violation count circuit. 2. The optical communication device according to 1. 3. An optical communication device for performing communication by optical transmission between a transmitting side having an optical transmitter and a receiving side having an optical receiver via an optical fiber cable or a space, provided on the transmitting side. A transmission monitoring timer circuit that does not continuously transmit a transmission signal for a predetermined time or more, and receives an output of the transmission monitoring timer circuit, and turns on T1 time after the output of the transmission monitoring timer circuit disappears. And a timing generation circuit for outputting a signal to be turned off after T2 time after the on, and an optical transmitter for adjusting the output level of the optical transmitter to a predetermined level while the output of the timing generation circuit is significant. Output level adjusting means, a carrier detection circuit provided on the reception side for detecting the presence or absence of a reception signal, and a predetermined timing based on an output of the carrier detection circuit. A timing signal generating circuit for outputting a timing signal of a predetermined time width T6 at the timing T5; a code transition rule violation detecting circuit for detecting a code transition rule violation of the received signal while the output of the timing signal is significant; A light counting circuit that counts the number of code transition rule violation detections output by the code transition rule violation detection circuit, and outputs a signal when the number of detections is equal to or greater than a preset value. Communication device. 4. An output level adjusting means of the optical transmitter, turns on and off a signal pulse inputted to the optical transmitter at a high speed during a time when the optical transmitter keeps outputting an optical output; 4. The optical communication apparatus according to claim 3, further comprising a blinking signal generation circuit capable of adjusting a time ratio between the on state and the off state.