JPS5844833A - Wide band communication system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides broadband signals for television and/or stereo broadcasting via subscriber lines consisting of original fiber groups connecting a relay station and each i'jo subscriber station. The present invention relates to a broadband communication system in which narrowband digital communication signals such as 6akbit/s digital telephone signals, teletext signals, 5kbit/s control signals, broadcast control-gram selection signals, etc. are transmitted. Note that in this specification, the term relay station is used to include the amount of distribution.

In broadband communication systems using original fiber cables, the subscriber line may consist of one original fiber cable used in the image transmission direction, or two original fiber cables used for each transmission direction. good. In the former case, current technology requires that the subscriber station be routed from the subscriber station to the relay station via a single original fiber cable through which broadband signals for television and/or stereo broadcasting are transmitted in the direction from the relay station to the subscriber station. Only control signals or relatively simple response signals for A-eye interaction services can be transmitted in the direction. Beyond that, for example, digital telephones,
A4 kbit/s digital signal (possibly in multiple channels) and s kb 1 (in some cases in multiple channels) for teletext, facsimile and for the broadcasting and synchronization of such narrowband communication services
If the t/s digital signal needs to be transmitted in both directions between the relay station and the subscriber station, the l12
The original fiber cable of the book was used (magazine "ntz
” 32 (19'i'9)3, No. 150-153
In this case, it is also possible to transmit video communication signals for video telephones via both optical fiber cables.

In such signal transmission via original fiber cables with different transmission directions, the signals to be distributed as one-way communication services, such as television and radio, and telephone, for transmission in the direction from the relay station to the subscriber station, The need for convergence of signals to be transmitted as two-way communications services, such as teleprinters and data communications, may result in interrelationships between communications services provided by different entities, which may be affected by communications policy or Undesirable for legal and technical reasons. For example, if an analog signal (FM or PPM signal) is used as the wideband signal on the subscriber side (to avoid the cost of adding a second decoder), the analog wideband signal is focused with the digital communication signal and relayed over the same original fiber cable. The transmission from the station to the subscriber station is required to be This is difficult and requires distortion-free and high linearity of the transmission system.

It is an object of the present invention to avoid the above-mentioned problems. According to the present invention, the television and (
or] a wideband signal for stereo broadcasting and a narrowband digital communication signal, for example, a4kbit/s.
In a broadband communication system in which digital telephone signals, broadcast program selection signals, etc. are transmitted in a multiplexed manner, each subscriber line consists of two original fiber cables, and one of the original fiber cables passes from the relay station to the relay station. Only broadband signals for television and/or stereo broadcasts are transmitted in one direction to the subscriber station, and all digital signals in both directions between the relay station and the subscriber station are transmitted via the original fiber cable in the other direction. This is achieved by a wideband communication system characterized in that narrowband communication signals are transmitted.

According to the invention, the distribution of television and stereo broadcast programs and bidirectional broadcasting within a broadband communication system can be realized on a single 1''A1 line, in some cases one after the other. Along with the benefits of gaining
The advantage is that the technology required for its realization already currently meets the practical requirements. In an embodiment of the invention, digital communication signals in the image transmission direction are transmitted over the local original fiber cable during respective allocated time slots. Thereby, it is not necessary to remove the mutual interference of the signals in the image transmission direction at the source signal stage using, for example, a color filter or an expensive directional coupler, but a simple coupler (approximately 3d13) can be connected to the other source fiber. It is sufficient to use it between the cable and the source fiber cable coming from the respective electrical-to-optical converter or the source fiber cable going to the respective optical-to-electrical converter.

Advantageously, broadband signals are analog modulated and transmitted over said one source fiber cable in a frequency division multiplexed manner, and digital communications signals are transmitted over said other source fiber cable in a time division multiplexed manner. It is advantageous to be transmitted.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 1 shows one embodiment of a broadband communication system according to the invention to the extent necessary for understanding the invention. In this broadband communication system, the subscriber line AI connecting the relay station vSL and the subscriber station T1n5t consists of two optical fiber cables using graded fibers with a core diameter of 50 μm and a cladding diameter of 150 μm. The T1n5t may be equipped with television and stereo broadcast receivers, digital telephones, facsimiles, teletext, keyboard and display devices, and the like.

After passing through one of the original fiber cables Lb, the relay station ■St
Only one-way transmission of broadband signals for television and/or stereo broadcasting takes place from to subscriber station Tln3t. Broadband signals of television programs to be transmitted to subscriber stations can be transmitted, for example, as described in German Patent Application Publication No. 2
828,662, Published Patent Application No. 2,932,588 or Published Patent Application No. 2,932,587, a broadband coupling network KFb is configured, for example, as a frequency modulator for shifting the broadband signal in question into a specific carrier frequency band. The original fiber cable is passed through the analog modulator MOD, a wideband signal multiplexer MUI for each user, which is composed of, for example, a plurality of band pass filters connected together on the output side, and the electrical/optical converter E10. Given to Lb. In addition, the wideband signal of the stereo broadcast program can be transmitted using an appropriate format, for example, an MSt15 type channel selection device S.
TM and an analog modulator MOD, and then a wideband signal multiplexer MUL shared with the wideband signal of the television program and an electro-optic converter E10. Where cable Lb is terminated on the subscriber station side.
After the electrical converter 0/E (two-band signal demultiplexer DEX is connected) there the signal is distributed to the TVE and to the stereo broadcast receiver STE via the connection line st.

Through the other optical fiber cable Ls, the relay station vSt
The transmission of all digital communication narrowband signals in both directions between and the subscriber station Tln St takes place. For relay stations vSt, for example Austrian patent no. 354527
Narrowband coupling network KF'S of the type known from No.
digital telephone signals (for example, 64 kbit/s) and facsimile signals relayed via the relay control unit v8, control signals (for example, 8 kbit/s), teletext signals, and the setting device Eb of the broadband coupling network KFb.
The confirmation signal generated from the subscriber station T1n'St is concentrated in a multiplexer MULv, which is provided for each subscriber tone, into a multiplexed signal, for example a time division multiplexed signal, to be transmitted to the subscriber station T1n'St. Also, from subscriber station T1n5t to relay station v
The multiplexed signal, especially the time-division multiplexed signal, arriving at St is demultiplexed into individual signals (e.g.
IT/s) digital telephone signals, facsimile signals, and relay control unit Vs (for example, 8 kbit/s
] Control signals, teletext signals, and wideband coupling network K
The program selection signal to be applied to the setting device Eb of Fb is distributed. The multiplexer MULV together with the demultiplexer DEXv, for example multiplexers ZD1000C1 and ZD10 for a 4 kbit/s multiplexed signal.
00EIO type and a 4 kbit/s signal of 20482
O48/s multiplexed signal (multiplexer D for combining two
It can be realized by SE 64/2 type and C2.

Similarly, the convergence and distribution of signals transmitted in the opposite direction to that described above takes place at the subscriber station T]nSt. for that,
Similar multiplexers MULI and demultiplexers DEXj are provided at the subscriber station.

At the relay station vSt, a multiplexer M U for each subscribed tone is used.
The output of L v is connected to the electrical input of the electro-optical converter e 10 , and the input of the demultiplexer DEXv is connected to the electrical output of the original-to-electrical converter e\0. The optical output ends or original input ends of these converters are connected to the original fiber cable Ls via a glass fiber directional coupler RKv.

Similarly (2. At the subscriber station Tln5t, the original fiber cable Ls is connected to the optical output end of the electro-optic converter O\e and the optical-electrical converter o/ through the glass fiber directional coupler RKt.
It is connected to the original input terminal of e, and is connected to the electric-optical converter 0
The electrical input of \e is connected to the output of the multiplexer MULt, and the electrical output of the original-to-electrical converter 0/e is connected to the input of the demultiplexer DEXj. Input end of multiplexer MULt and demultiplexer DE
The output of Xt is connected to individual narrowband communication terminals or subscriber equipment, the details of which do not need to be explained here.

Glass fiber directional couplers RK v and RKt also
For example, the magazine ° “Nano h Lichten Elektronik”
(Nachrichten Elektronik
)” (1979) 1.18, so there is no need to explain the details here.

As shown in Fig. 1, when the multiplexed signals in both transmission directions are transmitted through the original fiber cable Ls during the time slots assigned to each, the multiplexed signals in both transmission directions are There is no need to impose special conditions on the directional coupler regarding prevention of mutual interference.

To this end, in the broadband communication system shown in FIG. 1, multiplexers or demultiplexers MULv, DEXv in the relay station VSt and electric-to-original or ex-to-electrical converters e10. e\0, a buffer circuit Zv consisting of, for example, a shift register (two) is provided.Similarly, a buffer circuit Zv consisting of, for example, a shift register (two) is provided. A similar buffer circuit Zt is provided between the electrical converters 0\e and o/e.

This time allocation for each transmission direction at the stage of the optical signal is advantageous because the necessary balance circuitry can be realized with normal IC technology (e.g. by a shift register). Although the transmission bit frequency must be increased due to band allocation, there is no need to consider that this will have a disadvantageous effect when using an original fiber cable as a transmission path. This is because no interference radiation occurs, and transmission loss does not increase as the pit frequency increases, so the reachable distance is not affected as with copper wire cables.When allocating time slots In determining the transmission parameters of, for example, the pulse Hi & duration and the burst pause time, it is expedient to base the determination on the maximum possible reach when transmitting the signal via the original fiber cable.

An example of the time course of a burst transmission is shown in FIG. In this example, for Deca 1 with a duration of 25 μs,
A maximum signal transmission time of 00 μS was obtained, which corresponds to an original fiber cable length reach of approximately 20 km. This example is known per se from German Patent Application No. 2511619, in which bursts alternate in the picture transmission direction are in each case two successive <(12
It is based on a scheme in which digital signal words are transmitted in pulse frames (of 5 μs). In this case, the 2, o4s used anyway for digital relay
If the Mbit/s clock is also used as the bit clock during burst, if the burst duration is about 25 μS as mentioned above, then for example about 3 x 64 kbit
/s transmission capacity, i.e. for example two 64kbit
/a digital communications cable (e.g. for digital telephone and facsimile) and eight 5kbit/a
Transmission capacity for s digital communication channels (for broadcasting, synchronization and data transmission) is available.

FIG. 3 shows, as another embodiment of the present invention, a broadband communication system in which a digital videophone service is added in addition to the various iM communication services provided in the embodiment of FIG. . Relay station vSt and subscriber station 'I
The digital signals for image communication in both directions are also transmitted via the original fiber cable Ls, which transmits narrowband signals for digital communication in both directions between 'ln St.

FIG. 3 is illustrated to correspond to FIG.
What has been explained above with respect to the figures also applies to the embodiment of FIG. 3, so there is no need to repeat the explanation here. In FIG. 3, a video communication device VKA consisting of a camera and a display is added to the subscriber station T1n5t for bidirectional video communication (videophone). Video communication equipment V
KA is an analog-to-digital converter D\A in the transmit direction
via a multiplexer MUL t and, in the receive direction, via a digital-to-analog converter D/A to the output of a demultiplexer DEXt. An image communication coupling circuit network KFB is added to the relay station ■St, and its input terminal is connected to a multiplexer MULv.
and its output is connected to the demultiplexer D.
It is connected to the input end of E
It is controlled by and relays between the two edge communication lines.

For example, A4K in both directions via the original fiber cable Ls.
Alongside the telephone signals, facsimile signals and control signals (e.g. 8 kbit/s) at 8 Mbit/s or 34 Mbit/s (e.g. The multiplexers and demultiplexers required for this purpose are, for example, multiplexers DSMX2/8
(for 8Mbit/s digital signal) or DS
This can be realized by adding an MX8/34 type (for 34 Mbit/S digital signals).

An example of the time course of burst transmission is shown in FIG. In this example, 40
A maximum signal transmission time of μs is obtained, which is approximately 8k
Corresponds to the original fiber cable length (reaching distance) of m. In this case, for example 1 n OMb during each burst
For example, 8 kbit each at a transmission speed of it/s.
can be transmitted.

Finally, it should be mentioned that the image communication coupling network KFB shown in FIG. ) can also have a coupling point switching circuit.The same applies to the wideband coupling network KFb, as already shown in German Patent Application No. 32 04 900.

[Brief explanation of the drawing]

1 and 3 are diagrams showing embodiments of the broadband communication system according to the present invention, respectively, and FIGS. 2 and 4 are diagrams showing digital communication signals in the image transmission direction being transmitted during the respective allocated time slots. be done. A1...Subscriber line, DEX, DEXt, DEXv
...Demultiplexer, Eb...Setting device, E
lo. elo, o\e...Electric-optical converter, O/E, e\
0+O/e...Part-electrical converter, KF'b+
KFs...Coupling circuit network, KFB...Coupling circuit network for image communication, Lb+Ls...Original fiber cable, MOD...Analog modulator 1. MUL
t, MUL v... multiplexer, STE
...Stereo broadcast receiver, TV...Television receiver, 'I'ln St...Subscriber station, V8...Relay control distribution section, vSt...Relay station, VKA...Video communication Device.

Claims (1)

[Scope of Claims] 1) Broadband signals for television and/or stereo broadcasting and narrowband digital communication via a zero-channel line consisting of original fiber cables connecting a relay station and each subscriber station. In a broadband communication system in which signals such as a4 kbft/s digital telephone signal, broadcast program selection signal, etc. are transmitted in a multiplexed manner, each subscriber line consists of two original fiber cables (Lb, Ls), After passing through one of the original fiber cables (Lb),
Broadband signals for television and/or stereo broadcasting are only transmitted in one direction from the relay station (VSt) to the subscriber plane (Tin ST), and in the other direction via the original fiber cable (Ls) to the relay station. ■Transmission of all digital communication narrowband signals in both directions between St] and subscriber stations (T1n5t) 1. ,. 2) A digital communication system for two-way picture communication between the relay station (VSt) and the subscriber station (Tin St) via the other source fiber cable (L8). The broadband line communication system according to claim 1, characterized in that signal transmission is also carried out. 3) The broadband signal is analog modulated and transmitted to the one source fiber cable (Lb) using a frequency division multiplexing method. 3. A broadband line communication system according to claim 1 or 2, characterized in that the broadband line communication system is transmitted via. 4) Claims 1 to 3, characterized in that the digital communication signals in the image transmission direction are transmitted through the other original fiber cable (L81) during the respective allocated time slots. 5) The broadband communication system according to claim 4, wherein the digital communication signal is transmitted via the other original fiber cable (Lf) in a time division multiplexing system. broadband communication system.