JPS63284957A - Optical transmission system - Google Patents

Abstract

PURPOSE:To enable encoded code information system string to be transmitted as it is, by extracting the positive and the negative polarity of a ternary digit code information system string separately, and generating and transmitting two series of optical system strings based on the polarity. CONSTITUTION:At a transmitter 12, when the ternary digit code information system string 3 is inputted from a terminal 13, a signal 1 of positive polarity is sent to a light emitting element 19 by a code extraction circuit 15, and the signal 1 of negative polarity is sent to a light emitting element 20 by a code extraction circuit 16. The light emitting elements 19 and 20 perform the intensity modulation of light having wavelength lambda1 and lambda2 according to respective extracted code system string, and send them to an optical fiber 21. Meanwhile, at a receiver 22 side, a light receiving element 23 senses to only the light having the wavelength lambda1, and a light receiving element 24 senses to only the light having the wavelength lambda2, and they are reproduced at reproduction reception parts 25 and 26, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical transmission system using an optical transmission line, and in particular to a transmission line encoding system.

[Prior art] Figure 4 shows, for example, research practical application report Vol. 30 No. 12 (1
This is a time chart showing the conventional information transmission method using the rPCM24CPCM24C relay transmission pillar published on pages 1 to 19 of the publication published by Nippon Telegraph and Telephone Public Corporation in 1981.
l is the bit number, 2 is the information sequence to be transmitted, and 3 is the information sequence 2 that is to be transmitted as a bipolar with m Zeros substance.
A type of system in which m=
This is a code sequence encoded using an encoding method (hereinafter referred to as B8ZS encoding method) in the case of B8ZS.

Next, the operation will be explained. Code sequence 3 based on the B8ZS encoding method is an encoding method using ternary digits based on a bipolar code string, and in the bipolar code string based on information sequence 2 to be transmitted, "0" signals are continuous for 8 or more bits. 10011001" is used as the specific pattern in the illustrated example. This reduces the number of consecutive "0" signals to 7 bits or less. suppressed,
Bit sequence independence (Bit 5 sequence I) does not impose constraints on the binary code sequence.
-ndependence (hereinafter referred to as BSI), and has obtained good transmission quality.

[Problems to be Solved by the Invention] Since the conventional information transmission system is configured as described above, the information sequence is transmitted by the intensity of light by light intensity modulation, and is converted into three-value digits containing positive and negative signal components. When using an optical transmission line that is unsuitable for transmitting bipolar code sequences using 3-value denotation, the coded information sequence is converted back to a binary digit code using a ternary denotation method, and then converted to a binary digit code using pi-phase coding or mark code. It is necessary to perform speed conversion using insertion coding, etc., which poses a problem in that the device becomes complicated.

This invention was made to solve the above-mentioned problems, and is an optical transmission system that can directly transmit coded information sequences encoded by a coding method using ternary digits, such as a bipolar code sequence. The purpose is to obtain a method.

[Means for Solving the Problems] The optical transmission system according to the present invention separately extracts positive and negative polarity code sequences of a coded information sequence using ternary digits, and generates two systems of optical signals based on them. It generates a sequence and transmits it to an optical transmission line.

[Operation] The optical transmission system of the present invention generates two optical signal sequences for a coded information sequence using ternary digits, and separately transmits code sequences with positive and negative polarities.
By combining the two on the receiving side, an optical transmission system is realized that uses ternary digits and can directly transmit encoded information sequences encoded using the existing encoding system.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
In the figure, 1 is a bit number, and 3 is an encoded information sequence based on the B8ZS encoding method, which is the same as the conventional one denoted by the same reference numeral in FIG. 4.5 is an extracted code sequence extracted from this encoded information sequence 3; 6 is a first optical signal sequence generated for the encoded information sequence 4;
7 is a second optical signal sequence generated for the encoded information sequence 5, and this first optical signal sequence 6 emits light when the "1" signal of the encoded information sequence 3 has positive polarity. , the second optical signal series 7 emits light when the "■" signal of the encoded information series 3 has negative polarity. Further, 8 is a received code sequence corresponding to the first optical signal sequence 6, 9 is a received code sequence corresponding to the second optical signal sequence 7, and IO is reproduced based on these received code sequences 8 and 9. The reproduction timing 11 is also a reproduction code sequence reproduced from the received code sequence 8.9.

FIG. 2 is a block diagram showing an example of a transmitting device, and in the figure, 12 is the transmitting device, I3 is a terminal to which the encoded information series 3 is input, 14 is a terminal to which the transmitting clock is input manually, and ! Reference numeral 5 denotes a code extraction circuit 16 for extracting the positive polarity °l'' signal of the encoded information series 3 of three-valued digits manually inputted from the terminal 13 as an extraction code sequence synchronized with the transmission clock manually inputted from the terminal I4; Similarly,
a code extraction circuit that extracts a negative polarity "1" signal of the encoded information series 3 as an extraction code series synchronized with a transmission clock;
17. 18 is a buffer connected to each of these code extraction circuits 15°IO; 19 is a light emitting element that emits light of wavelength λ1 and is activated by the output of the buffer 17 to generate the first optical signal sequence 6; 20 emits light of wavelength λ, and buffer 1
A light emitting element 21 operates with the output of 7 to produce said second optical signal sequence 7, coupled to each of these light emitting elements 19, 20 to generate said first optical signal sequence 6 and second optical signal sequence 7. An optical fiber is an optical transmission line that transmits.

Further, FIG. 3 is a block diagram showing an example of a receiving device, and in the figure, 22 is a receiving device, 23 is coupled to the optical fiber 21 and is sensitive only to light of wavelength λ, and the first
A light receiving element 24 receiving the optical signal sequence 6 is also coupled to the optical fiber 2I and is sensitive only to light of wavelength λ,
A light-receiving element 25 receives the second optical signal sequence 7; 25 is a regenerative receiving unit that generates a reception code sequence 8 corresponding to the first optical signal sequence 6 from the output of the light-receiving element 23; a reproducing receiving unit 2 that reproduces the received code sequence 9 corresponding to the second optical signal sequence 7 from the output of the element 24;
Reference numeral 7 denotes a timing reproducing unit which reproduces the reproduction timing 10 based on the received code sequences 8 and 9 outputted from the two-dimensional reproduction receiving unit 25.26, and 28 denotes the reproduction receiving unit 25. 26 and the output of the timing reproducing section 27; 29 is a terminal for outputting the reproduced code sequence 11; and 30 is a terminal for outputting the reproduction timing 10.

Next, the operation will be explained. In the transmitting device I2, the terminal!
When an encoded information series 3 using ternary digits is manually inputted from terminal 14 and a transmission clock is inputted manually from terminal 14, the code extraction circuit 25 converts the positive polarity of the BI signal of the encoded information series 3 into the transmission clock. The code extraction circuit 16 similarly transmits the negative polarity of the encoded information sequence 3, the Bi signal. It is extracted in synchronization with the clock and sent to the light emitting element 20 via the buffer I8 as an extracted code sequence. The light emitting element I9 performs intensity modulation of the light having the wavelength λ1 according to the extracted code sequence 4 from the buffer 17, generates a first optical signal sequence 6, and sends it to the optical fiber 2I. Similarly, the light emitting element 20 performs optical intensity modulation of the wavelength λ according to the extracted code sequence 5 from the buffer 18, generates a second optical signal sequence 7, and transmits it to the optical fiber 2.
Send to 1. Therefore, the first optical signal sequence 6 emits light only when the I'' signal of the encoded information sequence 3 has positive polarity, and the second
In the optical signal series 7, light is emitted only when the "I" signal of the encoded information series 3 has negative polarity.

The first and second optical signal sequences 6.7 sent from the transmitting device 12 to the optical fiber 21 in this way are transmitted to the receiving device 22.
The light is then transmitted to the light receiving elements 23 and 24. The light-receiving element 23 receives the first optical signal sequence 6 by being sensitive only to the light having the wavelength λ, and the light-receiving element 24 receives the second optical signal sequence 7 by sensing only the light having the wavelength λ. This light receiving element 2
The output of 3 is sent to the reproducing receiver 25, and the output of the light receiving element 24 is sent to the reproducing receiver 26, where they are reproduced as received code sequences 8 and 9, respectively, and input to the timing reproducing circuit 27. The timing regeneration circuit 27 synthesizes these received code sequences 8.9 and then regenerates the regeneration timing IO by driving a tank circuit and a PLL circuit.
It is output from the terminal 30. On the other hand, playback reception ff12
The received code sequence 8.9 outputted from 5.26 is also input to the code reproducing unit 28, and the code reproducing unit 28 combines both of these received code sequences 8.9 and the reproduction timing 10 from the timing reproducing unit 27. The reproduced code sequence 11 is reproduced using the regenerated code sequence 11, and is outputted from the terminal 29.

In the above embodiment, one system of optical transmission line is shown, but two systems are prepared so that the first optical signal series and the second optical signal series are transmitted through different optical transmission lines. It's okay,
In that case, it is also possible to use light of the same wavelength for the first optical signal series and the second optical signal series.

Furthermore, in the above embodiment, the case where the encoding sequence using ternary digits is the B8ZS encoding method is explained.
Scrambled A M r (S scrambled
A Itternate Mark Inversio
n) Encoding method or 4B3T (4Binary
to 3 Ternary) encoding method, etc., and the same effect as the above embodiment is achieved.

[Effects of the Invention] As described above, according to the present invention, two optical signal sequences are generated for an encoded information sequence using ternary digits,
Since the code sequences for positive and negative polarities are transmitted separately and combined on the receiving side, the encoded information sequence by the encoding method using ternary digits can be
After returning to the binary digit code, it is possible to realize an optical transmission system that can transmit data as it is without speed conversion using pi-phase coding, mark code insertion coding, or the like.

[Brief explanation of the drawing]

FIG. 1 is a time chart showing an optical transmission system according to an embodiment of the present invention, FIG. 2 is a block diagram showing its transmitting device, FIG. 3 is a block diagram showing its receiving device, and FIG. 4 is a conventional optical transmission system. It is a time chart showing a transmission method. 2 is an information sequence to be transmitted, 3 is a coded information sequence, 6 is a first optical signal sequence, 7 is a second optical signal sequence, 12 is a transmitter, 2I is an optical transmission line (optical fiber), 22 is an Receiving device. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Figure 1 Figure 2 Figure 3 Figure 4 Special 80 turns

Claims (4)

[Claims] (1) In an optical transmission system in which a transmitting device and a receiving device are connected by an optical transmission path, and an information sequence by an optical signal is transmitted on the optical transmission path, the information sequence is encoded using a ternary digit encoding method. A first optical signal sequence generated by extracting only the code sequence of one polarity of the coded information sequence encoded by 2. An optical transmission system, characterized in that the optical transmission system transmits two optical signal sequences on the optical transmission path. (2) The light of the first optical signal series and the light of the second optical signal series are of different wavelengths, and the first and second optical signal series are transmitted on the same optical transmission path. The optical transmission system according to claim 1, characterized in that the optical transmission system transmits data. (3) The optical transmission system according to claim 1, wherein the first optical signal series and the second optical signal series are transmitted on separate optical transmission paths. (4) The optical transmission system according to claim 3, characterized in that the light of the first optical signal series and the light of the second optical signal series have the same wavelength.