JPS6356027A - Signal multiplexing and demultiplexing system and its equipment - Google Patents

Abstract

PURPOSE:To obtain a signal multiplexing/demultiplexing equipment not going to complicated constitution and large size by providing an input section or an extraction section of an optical signal to n-position of an optical fiber cable so as to input or extract the optical signal in the same timing. CONSTITUTION:A signal coming through signal lines 211-214 are supplied to AND gates 221-224 by a period of a pulse through a signal line 23 to simultaneously output the optical signal corresponding to the pulse width of the signals from electrooptic conversion elements 241-244. The signals are inputted from an end 25A of the optical fiber cable 25 and directional couplers 262-264 at the same time. Thus, the optical signal subject to time division multiplexing at intervals of a delay time tau by the optical fiber cable 25 coupling adjacent constitution of the end 25A and directional couplers 262-264 is sent through the optical fiber cable 25.

Description

[Detailed Description of the Invention] [Objective of the Invention 1 (Industrial Application Field) This invention relates to a method and device for multiplexing and demultiplexing n (n: an integer of 2 or more) channels of signals by time division. be.

(Prior Art) Conventionally, multiplexing and demultiplexing have generally been performed by electrical means. FIG. 5 shows the multiplexing section of the multiplexing/demultiplexing device. Four-channel electrical signals are applied to AND gates 21-24 via signal lines 11-14. 3 indicates a timing pulse generator, and the timing pulse generator 3 sequentially sends out pulses having a predetermined width to the AND gates 21 to 24 at non-overlapping timings via signal lines 41 to 44. . The outputs of the two AND gates 21 to 2 are made into time-series multiplexed signals via the OR gate 5 and sent out via the signal line 6. Thereafter, the electrical signal is converted into an optical signal when necessary. Further, FIG. 6 shows the demultiplexing section of the multiplexing/demultiplexing device. From the signal line 7, four channels of time-division multiplexed electrical signals are applied to latches 81-84. Reference numeral 9 indicates a timing pulse generator, and the timing pulse generator 9 sequentially generates pulses having a predetermined width through signal lines 101 to 104 to the latches 81 to 84 at non-overlapping timings.
give to Latches 81 to 84 (well, when a pulse is applied, they latch the signal applied from signal line 7. As a result, the signals of each of the four channels are output to signal lines 111 to 114. This separation In the case of the conversion section, before the signal line 7, conversion of an optical signal into an electrical signal is performed if necessary.

According to the above-mentioned multiplexing/demultiplexing method or device, it is necessary to sequentially generate pulses having a predetermined width for the number of channels at non-overlapping timings in the timing pulse generators 3 and 9. The disadvantages are that the generation control and configuration are complicated and the configuration becomes large.

(Problems to be Solved by the Invention) As described above, the conventional multiplexing/demultiplexing system or device has the disadvantage that the configuration becomes complicated and large. The present invention was made in view of the drawbacks of the conventional multiplexing/demultiplexing systems and devices, and its purpose is to provide a signal multiplexing/demultiplexing system and its device without complicating or increasing the size of the configuration. It is to provide.

[Structure of the Invention] (Means for Solving the Problems) In the method of the present invention, in a method of multiplexing and demultiplexing n-channel signals by time division, n points of an optical fiber cable forming one transmission path are used. An optical signal input section or an output section is provided in the n channels, each of the n channels is associated with an input section or an output section at each of the n locations, and the optical signal is transmitted to the input section or output section at the n locations. The information is input or taken out at the same timing. In addition, the device of the present invention includes an optical fiber cable forming one transmission path, an input section for an optical signal which is εQ-shifted at n points on the optical fiber cable, and an input section for transmitting each signal of the n channels to the input section. and signal sending means for sending signals at the same timing. Furthermore, in the device of the present invention, an optical fiber cable forming one transmission path and an
The optical signal extraction section provided at a location and the channel signal detection means for latching the signal obtained at the extraction section at the same timing and converting it into an n-channel signal are made exactly the same.

(Function) According to the above, the optical fiber l\ which forms one transmission line
Since signal input or signal extraction from the optical fiber that forms one transmission line is performed using n-channel frequency division timing, non-overlapping pulses are generated sequentially for the number of channels as in the conventional method. No configuration is required.

(Example) The present invention will be described in detail below with reference to the drawings. Fig. 1 shows a multiplexing section of a signal multiplexing/demultiplexing device adopting the method of the present invention. This multiplexing section has 4 channels. The signals are time-division multiplexed.

Electric signals are sent from the signal lines 211 to 214 for each channel. This (word is and gate 221-2
24. Also, and gates 221 to 224
The same pulse is applied via the signal line 23 from a pulse generator (not shown). This pulse is from signal line 211 to
214 at a rate synchronized with the rate of the transmitted signal. When a pulse is applied to the AND gates 221 to 224, the signals of the signal lines 211 to 21 pass through the AND gates 221 to 224 to the electrical/optical conversion elements 241 to 224.
It reaches 244. As a result, the electric/optical conversion elements 241 to 2
44, the signals of the signal lines 211 to 21 are simultaneously converted into optical signals and output. The optical signal output from the electrical/optical conversion element 241 is input from the end 25A of the optical fiber cable 25 and sent to the directional coupler 262 side. The optical signals output from the electrical/optical conversion elements 242 to 244 are
The signals are input to directional couplers 262 to 264 and transmitted in the direction of the arrow. By the way, the end 2 of the optical fiber cable 25
5A and the directional coupler 262, the directional coupler 262
The lengths of the optical fiber cables 25 connecting between the directional coupler 263 and the directional coupler 263 and between the directional coupler 263 and the directional coupler 264 are the same length, and the delay time due to the speed of optical transmission and , and the multiplexing speed of the optical fiber cable 25. That is, if light is propagated within the optical fiber cable 25 at the same propagation speed as in a vacuum,
A 30 cm fiber optic cable 25 can cause a delay of 1 n5ec. Therefore, if the above length is 30 cm, the maximum time slot for time division multiplexing is 1 n5ec.
As such, transmission is possible through 4 channels. On the other hand, the pulse width of the pulse given to the AND gates 221 to 224 is
The time width is equal to the time slot of the above-mentioned time division multiplexing. Moreover, the pulse interval of the above-mentioned pulses is the minimum time width until the optical signal input from the end portion 25A finishes passing through the directional coupler 264. The multiplexing unit configured as described above allows the signals @CH1 to CH4 that have arrived via the signal lines 211 to 214 to pass through the AND gates 221 to 224 for a pulse period as shown in FIG. Optical signals corresponding to the above pulse width are simultaneously outputted from the optical conversion elements 241 to 244, and these signals are simultaneously output to the ends 25A1 of the optical fiber cable 25 and the directional couplers 262 to 244.
It is input from H.264. End portion 25A, directional coupler 26
Optical signals CH1 to CH4, which are time-division multiplexed at intervals of delay time τ by the optical fiber cable 25 that connects 2 to 26 adjacent components, are transmitted through the optical fiber cable 25 as shown in FIG. .

In the above, the end portion 25A, the directional couplers 262 to 26
4 is an input section for optical signals, and AND gates 221 to 22
4. The electrical/optical conversion elements 241 to 244 and a pulse generator (not shown) constitute a signal sending means.

FIG. 3 shows a demultiplexing section of a signal multiplexing/demultiplexing apparatus employing the method of the present invention. This demultiplexing section is opposite to the multiplexing section shown in FIG. 1, and handles four-channel signals. From the optical fiber cable 31, time-division multiplexed optical signals CH4 to CH1 as shown in FIG. 4 arrive. These optical signals are output from the directional couplers 321 to 323 and the end portion 31A of the optical fiber cable 31. Directional couplers 321-32
3. The length of the optical fiber cable 31 that connects adjacent components of the end portions 31A of the optical fiber cable 31 is the same as that of the end portion 25A of the optical fiber cable 25 in the multiplexing section in FIG. 1, and the directional coupler. It is equal to the length of the optical fiber cable 25 connecting 262 to 26 adjacent configurations, and the delay time of each interval is also equal. Therefore, when the optical signal CH4 of the channel by the signal line 214 of FIG. 1 is output from the end 31A of the optical fiber cable 31, the signal line CH4 of the channel shown in FIG. Optical signals CH3 to CH1 of channels by 213 to 211
will be output. Directional couplers 321 to 323
The optical signals outputted from the end portion 31A of the optical fiber cable 31 are applied to optical/electrical conversion elements 331-334, converted into electrical signals, and applied to latches 341-344. The same pulse is applied to the latches 341 to 344 via the signal line 35 from a pulse generator (not shown) to provide latch timing.
is the optical/electrical conversion element 3 at the timing when the pulse is applied.
The signals given from 31 to 334 are latched. In the pulse generating section, a detecting section (not shown) is connected to an optical fiber cable 3.
1, the signal line 214 in FIG.
The pulse generation starts when the optical signal CH4 of the channel is detected. This pulse generator generates a pulse having the same pulse width and the same pulse interval as the pulse generated by the pulse generator described in FIG. 1.

In the demultiplexing section configured as described above, time-division multiplexed optical signals CH4 to CH1 as shown in FIG. 4 arrive via the optical fiber cable 31.

Then, as the optical signal propagates through the optical fiber cable 31 that connects the directional couplers 321 to 323 and the adjacent components of the end portion 31A of the optical fiber cable 31, the signal of each channel is transferred to the optical/electrical conversion element. 331-334
are simultaneously output to the latches 341-3 and converted into electrical signals.
Sent to 44. At this timing, a pulse is applied from the signal line 35, and the latches 341 to 344 latch the signals CH1 to CH4 of each channel.

As a result, the electrical signals CH1 to CH4 of each channel are sent to the signal lines 361 to 364 as shown in FIG. 4.

In the above, the directional couplers 321 to 323, the end portion 31
A is an optical signal extraction part, and optical/electrical conversion elements 331 to 3
34, latches 341 to 344, and a pulse generator (not shown) are channel signal detection means.

In the above embodiment, signal gate control (by AND gates 221-224) and latches (latches 341-224)
344) was performed electrically, but it may also be performed optically. In this case, electrical/optical conversion is performed before gate control, and optical/electrical conversion is performed after latching.

[Effects of the Invention] As explained above, according to the present invention, since multiplexing and demultiplexing are performed using the delay caused by the optical fiber cable, it is only necessary to input and extract signals on all channels at the same timing.
Compared to the conventional example, which requires timing control for each channel in accordance with the multiplexing speed, the configuration can be simplified and made smaller.

[Brief explanation of drawings]

Figures 1 and 3 are configuration diagrams of an embodiment of the present invention, Figure 2,
FIG. 4 is a timing diagram for explaining the operation of the embodiment shown in FIGS. 1 and 3, respectively, and FIGS. 5 and 6 are block diagrams of conventional signal multiplexing and demultiplexing apparatuses. 241 to 244...Electrical/optical conversion elements 25, 31...
・Optical fiber cable 262-264.321-323...Directional coupler 3
31 to 334... Optical/electric conversion elements 341 to 344.
...Latch Agent Patent Attorney Book 1) Takashi Figure 1 Figure 3 CH. Figure 2 Figure 4

Claims (6)

[Claims] (1) In a method for multiplexing and demultiplexing n-channel signals by time division, an optical signal input section or an output section is provided at n locations of an optical fiber cable forming one transmission path, and each of the n channels is and an input section or an extraction section at each of the n locations, and the optical signal is inputted or extracted at the same timing at the input section or extraction section at the n locations. Separation method. (2) A claim characterized in that adjacent input sections or output sections are provided in an optical fiber forming one transmission path so that the delay time of optical transmission between them is equal. The signal multiplexing/demultiplexing method described in paragraph (1). (3) An optical fiber cable forming one transmission line,
A signal multiplexing and demultiplexing device comprising optical signal input sections provided at n locations of this optical fiber cable, and signal sending means for sending out each signal of n channels to the input section at the same timing. (4) The signal multiplexing/demultiplexing device according to claim (3), wherein adjacent input sections are provided at locations where the optical transmission delay time between them is equal. (5) an optical fiber cable forming one transmission path;
A signal comprising an optical signal extraction section provided at n locations of this optical fiber cable, and a channel signal detection means that latches the signals obtained at the extraction section at the same timing and converts them into n-channel signals. Multiplexing/demultiplexing equipment. (6) The signal multiplexing/demultiplexing device according to claim (5), wherein adjacent extraction sections are provided at locations where the optical transmission delay time between them is equal.