JPS62219829A - Optical signal transmission and reception equipment - Google Patents

Abstract

PURPOSE:To send a data signal as an optional waveform and to attain stable reproduction by applying wavelength multiplex to a data signal and a conduction check signal, sending the result through one optical transmission line, separating them after reception and detecting the conduction check signal so as to check the state of the optical transmission line. CONSTITUTION:A serial data signal to be sent is converted into a code decoded easily at the reception side by a coding circuit 12, and a light emitting element 14 is lighted according to the coded signal by a drive circuit 13. Then the DC level signal with high stability of a conduction check signal generator 16 is converted into an optical signal with a different wavelength from that of a light emitting element 14 by a light emitting element 17, both the optical signals are overlapped by an optical signal multiplexer 15 and the result is sent to an optical transmission line 18. The signal is demultiplexed according to the frequency component by a demultiplexer 20 of the optical signal reception section 19, the data signal and the conduction check signal are converted into electric signal by photodetectors 21, 25 and amplified by amplifiers 22, 26. Further, the output of the DC amplifier 26 represents the light attenuation of the line 18, compared with the previously set level by the conduction check circuit 27 and if the level is lower, the result is outputted as a light interruption signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a nine optical signal transmitting and receiving device in which an optical signal transmitter and an optical signal receiver are connected through an optical transmission line.

[Conventional technology]

Figure 2 shows, for example, the digital optical transceiver module MP published in the catalog of Mitsubishi Electric Corporation's "Mitsubishi Optical Communication Equipment".
The functional plan of the conventional optical signal transmitting/receiving device equipped with a disconnection detection function shown in the -010DF series is shown. In Figure 2, 1 is an encoding circuit, 2 is a drive circuit, and 3 is an LED.
4 is a light receiving element such as a PIN 7 photodiode, 5 is a preamplifier, 6 is an AGC amplifier, 7 is a comparator,
8 is a composite circuit, 9 is a full-place detection circuit, 10 is an optical transmission line connecting the light emitting element and the light receiving element 4, and 11 is a DC amplifier.

Next, the operation will be explained. A serial signal for data signal transmission is input to the encoding circuit 1 as a binary electric signal. In the encoding circuit 1, a pulse train is added to a constant biased DC signal, which becomes a positive value if the data signal value is "1", and a negative value if the data signal value is "0". Add together the pulse trains. Figure 3 shows the state of this encoding, where (a) shows the data signal, (a) shows the data signal, and (
b) is a coded signal.

The drive circuit 2 converts the encoded electrical signal into an optical signal by so-called optical intensity modulation that changes the intensity of the optical signal from the light emitting element 3 according to the magnitude of the voltage, and outputs the signal.

On the receiver side, the optical signal received by the light receiving element 4 is converted into an electrical signal depending on the optical signal intensity. The alternating current signal component of this electric signal is once amplified by a constant gain by the preamplifier 5 and sent to the AGC amplifier 6.

On the other hand, the DC signal component of the received electrical signal is amplified by a constant gain by the DC amplifier 11 and sent to the gain control section of the AGC amplifier 6. The AGC amplifier 6 amplifies the received AC signal component with an amplification factor inversely proportional to the DC component of the next signal.

As a result, the AC signal component is sent to the comparator 7 as a signal at a substantially constant level regardless of the input signal level. The comparator 7 determines whether the AC signal component is a positive signal or a negative signal, and sends the determination result to the decoding circuit 8. The decoding circuit 8 reproduces the original data signal accordingly.

FIG. 4 shows the state of this reproduction, in which (a) shows the encoded signal and (b) shows the decoded data signal.

On the other hand, if neither a positive signal nor a negative signal is sent from the comparator 7, the full place detection circuit 9 determines that the optical signal is disconnected and outputs an optical signal disconnection signal.

[Problem that the invention seeks to solve]

Since conventional optical signal transmitting and receiving devices are configured as described above, it is necessary to perform special encoding on input data signals, which requires a special circuit, and also requires a special circuit to perform encoding. The generation speed of the pulse train must be faster than the original data signal, and the transmission speed of the data signal is limited by this K, creating problems such as not being able to fully utilize the capabilities of the opto-electrical converter. .

This invention was made in order to solve the above-mentioned problems, and it is possible to transmit data signals completely independently as arbitrary signal waveforms without considering the optical transmission check function. The purpose of the present invention is to provide an optical signal transmitting and receiving device that can improve the stepping stone check function and reproduce data signals more stably.

[Means for solving problems]

The optical signal transmitting/receiving device according to the present invention superimposes a data signal and a continuity check signal by wavelength multiplexing, transmits them on one optical transmission path, separates both signals after receiving them, and performs optical transmission by detecting the continuity check signal. This makes it possible to check the road condition.

[For production]

The continuity check signal in this invention is superimposed with a data signal by a multiplexer and transmitted over a single optical transmission line, and then separated and regenerated by a demultiplexer on the receiving side to check the state of the optical transmission line. do.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 11 is an optical signal transmitter, and this optical signal transmitter 11 includes an encoding circuit 12, a drive circuit 13, a first light emitting element 14, an optical signal multiplexer 15, and a continuity check signal generator 16.
, a second light emitting element 17. 18 is an optical transmission line, 19 is an optical signal receiving section, and this optical signal receiving section 19
is an optical signal demultiplexer 20. light receiving element 21, preamplifier 22,
It is composed of an AGC amplifier 23, a decoding circuit 24, a light receiving element 25, a DC amplifier 26, and a continuity check circuit 27.

Next, the operation 9 of this embodiment will be explained. Encoding circuit 12
A serial data signal to be transmitted is input. This encoding circuit 12 converts the input data signal into a code that can be easily decoded on the receiving side. This encoding method may be arbitrary, and in some cases, encoding may not be necessary.

When encoding is not performed, the data signal is directly input to the drive circuit 13. The drive circuit 13 causes the light emitting element 14 to emit light according to the encoded signal.

On the other hand, the continuity check signal generator 16 generates a continuity check signal. This continuity check signal is, for example, a DC level signal with extremely high stability. The continuity check signal is applied to the light emitting element 17 and converted into an optical signal. Here, it is assumed that the light emitting element 14 and the light emitting element 17 have different emission wavelengths. For example, with a wavelength of 810 μm,
It is preferable to use a wavelength of 890 μm for each.

The optical signal multiplexer 15 superimposes the optical signal from the light emitting element 14 and the optical signal from the light emitting element 15, and sends it out to the optical transmission line 18 as one optical signal. The optical signal that has passed through the optical transmission line 18 is input to an optical signal receiving section 19 .

The input optical signal is demultiplexed into two signals by the optical signal demultiplexer 20 according to the frequency components of the optical signal.

Of these, the data signal is converted into an electrical signal by the light receiving element 21, and is amplified by a constant gain by the preamplifier 22.

On the other hand, the continuity check signal, which is another demultiplexed signal, is converted into an electrical signal by the light receiving element 25 and amplified by the DC amplifier 26. The output of this DC amplifier 26 indicates the amount of optical attenuation of the optical transmission line 18. In other words, the continuity check signal is kept at a constant level on the emitting side, and the level on the receiving side is kept at a constant level on the optical transmission line 1.
It depends on the attenuation amount of 8.

The output of the DC amplifier 26 is input to a continuity check circuit 27, where it is compared with a predetermined level, and if it is lower than this level, it is determined that there is an optical transmission threshold and output as a sufficient signal.

Furthermore, the output of the DC amplifier 26 indicates the amount of attenuation of the optical transmission line 18, and it is also possible to output this output from the optical signal receiver 19 in order to use it as a signal indicating the state of the optical transmission line 18. be able to.

Furthermore, if the output of the DC amplifier 26 is converted and output, it can be directly used in a digital circuit as a code signal indicating the state of the transmission path. The output of the DC amplifier 26 can be used to determine the amplification factor of the AGC amplifier 23 for the data signal.

As a result, amplification is performed according to the amount of attenuation of the optical transmission line 18, and the output from the AGC amplifier 23 is always maintained at a constant level.

The data signal output from the AGC amplifier 23 is input to the post-coding circuit 24, where decoding corresponding to the encoding on the transmitting side is performed, and the original data signal is reproduced and output.

〔Effect of the invention〕

As described above, according to the present invention, since the data signal and the continuity check signal are configured to be generated and reproduced independently, not only can arbitrary encoding be performed as the data signal, but also Since the transmission speed is not limited by encoding, signals can be transmitted at higher speeds, and a break in the optical transmission line is detected using the continuity check signal, so an optical signal transmitting and receiving device with an advanced optical transmission checking function can be obtained. effective.

[Brief explanation of drawings]

FIG. 1 is a functional block diagram showing an optical signal transmitting/receiving device according to an embodiment of the present invention, FIG. 2 is a functional block diagram showing a conventional optical signal transmitting/receiving device, and FIG. 3 shows an example of data signal encoding. FIG. 4 is a time chart showing an example of decoding a data signal. 11 is an optical signal transmitter, 14 and 17 are light emitting elements, 15 is an optical signal multiplexer, 16 is a continuity check signal generator, 18 is an optical transmission line, 19 is an optical signal receiver, and 20 is an optical signal demultiplexer. %2
1-25 is a light receiving element, 24 is a decoding circuit, and 27 is a continuity check circuit. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In an optical signal transmitter/receiver in which an optical signal transmitter and an optical signal receiver are connected by an optical transmission line, a first light emitting element converts a serial signal for data transmission into an optical signal, and a continuity check signal generator outputs a a second light-emitting element that converts a continuity check signal of the optical transmission line into an optical signal; and a second light-emitting element that superimposes optical signals from the first and second light-emitting elements having different emission wavelengths to form the optical transmission line. An optical signal multiplexer for sending out is provided in the optical signal transmission section, an optical signal demultiplexer for demultiplexing the optical signal input from the optical transmission line according to frequency components, and an optical signal multiplexer for demultiplexing the optical signal input from the optical transmission line, and an optical signal multiplexer for demultiplexing the optical signal input from the optical transmission line, a first light-receiving element for converting into a signal; a second light-receiving element for converting the demultiplexed continuity check signal into an electrical signal; and decoding for reproducing a data signal based on the electrical signal from the first light-receiving element. An optical signal transmitting/receiving device characterized in that the optical signal receiving section is provided with a circuit and a continuity check circuit for checking the state of the optical transmission line based on the electrical signal from the second light receiving element.