CA1204230A - Broadband communication system - Google Patents
Broadband communication systemInfo
- Publication number
- CA1204230A CA1204230A CA000427986A CA427986A CA1204230A CA 1204230 A CA1204230 A CA 1204230A CA 000427986 A CA000427986 A CA 000427986A CA 427986 A CA427986 A CA 427986A CA 1204230 A CA1204230 A CA 1204230A
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- Prior art keywords
- signals
- digital
- optical waveguide
- subscriber station
- communication system
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- 238000000034 method Methods 0.000 claims abstract description 10
- 230000002457 bidirectional effect Effects 0.000 claims abstract description 6
- 230000001747 exhibiting effect Effects 0.000 abstract description 5
- 230000011664 signaling Effects 0.000 abstract description 2
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- 101100301524 Drosophila melanogaster Reg-5 gene Proteins 0.000 description 2
- 208000003251 Pruritus Diseases 0.000 description 2
- 230000007175 bidirectional communication Effects 0.000 description 2
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
- H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
- H04Q11/0478—Provisions for broadband connections
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J2203/00—Aspects of optical multiplex systems other than those covered by H04J14/05 and H04J14/07
- H04J2203/0001—Provisions for broadband connections in integrated services digital network using frames of the Optical Transport Network [OTN] or using synchronous transfer mode [STM], e.g. SONET, SDH
- H04J2203/0028—Local loop
Abstract
ABSTRACT OF THE DISCLOSURE
In an optical broadband network having subscriber lines respectively extending between a switching center and a subscriber station and exhibiting a respective optical wave-guide, all digital communication narrow band signals, for 64 kbit/s digital telephony, facsimile, 8 kbit/s signaling, synchronization, data transmission and bidirectional picture telephone digital signals between the switching center and the subscriber station and vice-versa are transmitted over the optical waveguide, being respectively transmitted in accordance with time-division multiplex techniques in the discrete time slot method.
In an optical broadband network having subscriber lines respectively extending between a switching center and a subscriber station and exhibiting a respective optical wave-guide, all digital communication narrow band signals, for 64 kbit/s digital telephony, facsimile, 8 kbit/s signaling, synchronization, data transmission and bidirectional picture telephone digital signals between the switching center and the subscriber station and vice-versa are transmitted over the optical waveguide, being respectively transmitted in accordance with time-division multiplex techniques in the discrete time slot method.
Description
~Za~230 BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to a broadband communication system having optical waveguide subscriber lines for digital communication signals, for example, 64 kbit/s digital telephone signals, picture screen text signals, 8 kbit/s control signals, 34 Mbit/s moving picture communication -signals, respectively transmitted between an exchange center and a subscriber station.
Description of the Prior Art In an optical waveguide broadband communication system, the subscriber lines can respectively exhibit a single optical waveguide exploited in both transmission direction or, on the other hand, two respective separate optical waveguides for the ~o directions of transmission. In the former case, television (TV) and/or audio broadband signals are transmitted over the optical waveguide from the exchange center to the subscriber station, but, given a prior state of wavelength multiplex technique, only control signals or relatively simple replies, given interactive services, can be transmitted in a return channel from the subscriber station to the exchange center. When, proceeding beyond that, 64 kbit/s digital signals (if necessary, a plurality of 8 kbit/s digital signals), for example, or digital telephony, picture screen text, facsimile and for signaling and synchronizing such narrow band communication services, are to be transmitted between the subscriber station and the switching center or, respectively, in the reverse direction, then two optical waveguides per subscriber termination can be provided, in particular, a separate optical waveguide for each direction of transmission NTZ, Vol. 32, No. 3, 1979, pp. 150-153), whereby video commun-ication signals for a picture telephone communication can, under certain conditions, also be conducted over the two optical waveguides.
Such a signal transmission over transmission direction-associated optical waveguides for the transmission in the direction to~ards the subscriber station requires a bundling of TV and, if necessary, stereo audio signals to be distributed in the frame~ork of uni.directional communication services, such as television and radio having telecommunication signals to be transmitted within the frame~ork of bidirectional communication services such. as, for example, telephony, telegraphy, data communication, and therefore, under certain condi.tions, entails a linkage of commun;cation services of different operators ~hich can be undesirable for legal reasons, for telecommunication policy reasons or for technical reasons as ~ell. In order to avoid this, as already specified in our Canadi.an application Serial No. 408,176 filed July 27, 1982, a broadband communication system having subscriber lines for T~ and/or stereo audio broadband signals exhibiting two respective optical ~aveguides and respectively extending be-tween an exchange center and a subscriber station for digital communication signals wh;ch are narro~ band in comparison thereto, in which broadhand signals are transmitted in multi-plex over the one optical waveguide from the exchange or, respectively, di~tribution center to the subscriber station and di.gital communication narro~ band signals, particularly 64 kbit/s digital signals, as well as program selection signals, are transmitted in multiplex over the other optical waveguide from the subscriber station to the exchange or, respectively, 12~4230 distribution center, can also be designed such that only the TV and/or stereo audio broadband signals are transmitted over one optical waveguide from the exchange or, respectively, distribution center to the subscriber station and all digital communication narrow band signals and, if necessary, bi-directional moving picture communication data signals as well, are transmitted over the other light waveguide between the exchange center and the subscriber station and vice-versa, whereby the digital communication signals of the two transmission directions can be transmitted over the other optical waveguide in the discrete time slot method. In such a broadband communication system, the TV and stereo audio program distribution, on the one hand, and the bidirectional narrow band digital communication and, under certain conditions, the picture telephone digital communication, on the other hand, can be realized independently of one another, as well as successively under certain conditions.
SUMMARY OF THE INVENTION
-A broadband communication system having optical waveguide subscriber lines, however, need not always also provide a transmission of TV and/or stereo audio signals to be distributed in the framework of unidirectional communication services such as television and radio but, rather, can also provide a transmission of telecommunication signals solely in the framework of bidirectional communication services such as telephony, telegraphy, data communication and moving picture communication and the object of the present invention, there-fore, is to iprovide a broadband communication system particularly suited for this purpose.
12()4Z30 The present invention relates to a broadband communication system having subscriber lines for broadband signals and, in contrast thereto, narrowband digital commun-ication signals, the subscriber lines each comprising an optical waveguide connected bet~een an exchange centre and a subscribe.r station, characterized in that digital communic-ation narrowband signals and bidirectional picture communic-ation digital signals of both transmission directions between the exchange centre and the subscriber station and vice-versa are transmitted in accordance with a discrete time slot method over a single optical waveguide forming a subscriber line.
In conjunction with the fact that the technology required for its realization already meets practical require-ments today, the invention offers the advantage that a decoupling of the signals of the t~o transmission directions, for example, by way of color filters or high-grade directional couplers is not necessary in the optical level but, rather, a simple (for example, 3 dB) coupler between the optical wave-guide, on the one hand, and an optical waveguide coming froma re~pective electro-optical transducer or, respectively, an optical ~aveguide leading to the respective opto-electrical transducer, on the other h.and, adequately suffices.
According to a further feature of the invention, the digi.tal communication signals of a res.pective transmission direction can be advantageously transmitted over the optical ~avegui.de bundled in accordance with time-division multiplex techniques.
~2()4230 BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention, its organization, cons~ruction and operation will be best understood from the following detailed description, taken in conjunction with the accompanying drawings, on which:
FIG. 1 is a schematic diagram of an exemplary embodiment of a broadband communication system constructed in accordance with the present invention; and FIG. 2 is a schematic representation illustrating the chronological sequence of a digital transmission in accordance with the discrete time slot method for a broad-band communication system of the type illustrated in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
-FIG. 1 of the drawing schematically illustrates an exemplary embodiment of a broadband communication system according to the invention in a scope necessary for an under-standing of the invention. In this broadband communication system, a subscriber station Tln St is connected over a subscriber llne Al exhibiting an optical waveguide L formed, for example, by a gradient fiber having a 50 ~ core diameter and a 150 ~ ~acket diameter, to the appertaining exchange center VSt, whereby it is indicated in FIG. 1 that the subscriber station Tln St can be equipped for digital telephony, facsimile service, picture screen text, push-button dialing and display indication and can also be equipped, with a video communication system VKA having a camera and picture screen device, for bidirectional moving picture com~unication (picture telephony).
All digital communication narrow band signals, as well as bidirectional picture communication digital signals, are transmitted from the exchange center VSt to the sub-scriber station Tln St and in the reverse direction, from the subscriber station Tln St to the exchange center VSt, over the optical waveguide L. Thereby, for example, in the manner known from the Australian Letters Patent 354,527 or, respectively, United States Letters Patent 4,025,725, digital telephone signals (for example 64 kbit/s), facsimile signals and control signals (for example 8 kbit/s) as well as picture screen text (Btx) signals switched through in the exchange lQ center VSt over a narrow band switching matrix network KFs are combined ~ith picture communication signals switched through over a picture communication switching matrix network KFV, like~ise controlled by the exchange control Vs to form a multiplex signal to be transmitted to the subscriber station Tln St, for example, an 8 Mbit/s or a 34 Mbit/s time-division multiplex signal. A multiplex signal, particularly a time-division multiplex signal, proceeding in the reverse trans-mission direction from the subscriber station Tln St to the exchange center VSt i5 fanned out in the corresponding de-multiplexer DEXv into the corresponding individual signals,for example, digital telephone signals (for example 64 kbit/s) and facsimile ~ignal, control signal (for example 8bit/s) as ~ell as picture screen text signals s~itched through over the narro~ ~and s~itching net~ork KFs and digital picture tele-communication signal s~itched through over the picture communi.cation s~itching matrix net~ork KFB.
~ corresponding si.gnal bundling or, respecti.vely, debundling, corresponds in the subscriber station Tln St, respectively in the reverse transmission direction, to ~hich 3Q end a corresponding multiplexer MULt and a corresponding ~ .
423~
demultiplexer DEXt are provided.
The multiplexer MUL and the demultiplexer DEX can for example, be realized with commercially available multiplex devices such as the Siemens ZD1000 Cl and ZD1000 E10 for a 64 kbit/s multiplex signal and a commercially available multiplex device such as the Siemens DSE 64 k/2 for the combination of 64 kbit/s signals into a 2,048 Mbit/s multiplex signal, as well as with a commercially available multiplex device such as the Siemens DSMX2/8 (given an 8 Mbit/s digital signal) and, in addition, the DSMX8/34 (given a 34 Mbit/s digital signal).
As likewise indicated in FIG~ 1, the telephone terminal is connected in the transmission direction to a corresponding input of the multiplexer MULt by way of an analog/digital converter a/d and is connected in the receiving direction to a corresponding output of the demultiplexer DEXt via a digital/analog converter da. The video communication system VKA is connected in the transmission direction to a corresponding input of the multiplexer MULt via an analog/
digital converter D/A and is connected in the receiving direction to a corresponding output of the demultiplexer DEXt via a digital/analog converter D/A.
The electrical terminal of an electro-optical transducer e/o is connected in the exchange center VSt to the output of the subscriber-associated multiplexer MULv. The input of the demultiplexer DEXv provided in the exchange center VSt is connected to the output of an opto-electrical transducer o/e. The optical terminals of these two transducers are connected to the optical waveguide L via a glass fiber directional coupler RKv. In a corresponding manner, the lZ~4230 optical waveguide L is connected in the subscriber station Tln St over a glass fiber directional coupler RKt to the optical output of an electro-optical transducer e/o and the optical input of an opto-electrical transducer o/e, whereby the electrical input of the electro-optical transducer e/o is connected to the output of the multiplexer MULt and the electrical output of the opto-electrical transducer o/e is connected to the input of the demultiplexer DEXt. The individual narrow band communication terminals or,respectively, subterminals as well as the video communication system VKA
are then connected to the inputs of the multiplexer MULt or, respectively, to the outputs of the demultiplexer DEXt, without the necessity of further explanation here.
The glass fiber directional couplers RK, which like-wise need not be explained in greater detail here since glass fiber directional couplers are known p r se, for example from the publication Nachrichten Elektronik (1979) 1,18), are not subjected to any special requirements concerning the decoupling of the multiplex signals of the two transmission directions from one another when, as is likewise indicated in FIG. 1, the multiplex signals of the two transmission directions are transmitted over the optical waveguide L in accordance with the discrete time slot technique. In the broadband communi-cation system illustrated in FIG.l, provided in the exchange center DSt for that purpose between the multiplexer MULv or, respectively, the demultiplexer DEXv and the electro-optical transducer e/o or, respectively, the opto-electrical trans-ducer o/e is, for example, a buffer circuit Zv to be realized with a shift register. In a corresponding manner, a corre-sponding discrete time slot buffer circuit Zt is provided in the subscriber station Tln St between the multiplexer MULt and 121~)4Z30 the demultiplexer DEXt, on the one hand, and the electro-optical transducer e/o and the opto-electrical transducer o/e on the other hand.
The displacement of the actual direction separation from the optical level into the electrical (and digital) level therefore effected has the advantage that the discrete time-slot control circuits Zv, Zt may be realized in traditional integrated circuit (IC) technology (for example, with shift registers). The fact connected with the employment of the discrete time-slot method that the bit repetition rate in the signal bursts on the line amounts to a multiple of the useful bit rate can advantageously remain out of consideration given use on the optical waveguide L because, on the one hand, no high-frequency unwanted radiation occurs here and, on the other hand, the line attenuation of the optical waveguide does not rise with an increasing bit rate, i.e. the range thereof is not influenced as given a copper (Cu) line. It is there-fore advantageous when determining the parameters for the discrete time-slot transmission of, for example, burst length and burst pause, to base these on the maximally-possible range given signal transmission over an optical waveguide.
An example of the chronological sequence of a corresponding burst transmission is illustrated in FIG. 2.
According to this example, a maximum signal transit time of 40 ~s per transmission direction is available for an 80 ~s long digital signal block (burst), this corresponding to an optical waveguide length (range) of approximately 8 km. Within each burst, for example, 8 kbit/s can be respectively trans-mitted with a transmission rate of, for example, 100 Mbit/s.
In conclusion, it should also be pointed out that 120423~) the image switching matrix network KVB indicated in FIG. 1 can comprise crosspoint circuits realized in ECL technology which are formed by controllable multiplexers interconnected to form multi-stage crosspoint pyramids, as has already been described in the German Letters Patent 3,204,900.5, Electronics, March 24, 1982, pp. 41E, 42E.
According to FIG. 3, a broadband switching network having crosspoint circuits realized in ECL technology is provided for switching or, respectively, distributing communication signals, the crosspoint circuits being formed by controllable multiplexers 151, 152, 153...851, 852, 853, whereby the controllable multiplexers are interconnected to form multi-stage crosspoint pyramids KPPl...KPP8 respectively comprising a serving line ttl....tt8 and a plurality of shared offering lines pl...pl6. Thereby, eight crosspoint pyramids KPPl...KPP4, KPP5...KPP8 respectively comprising an individual serving line ttl...tt4, tt5...tt8 and sixteen shared offering lines ~...pl6 are illustrated or,respectively, indicated in FIG. 3. These, combined on a large scale integration (LSI) module (preferably on a gate array of the E2CL-100 master/module family of Siemens SH100 (described, for example, in the Siemens Data Sheets integrated circuits-SH100 Family-Design Kit-Cell Library, and in the Siemens publication Gate Arrays-Masken-Programmierbare Logikschaltungen, 1981 Edition, Order No. No. B/2363), form a broadband switching matrix module 16/8. Each crosspoint pyramid KPPl...KPP8 which, in the example, exhibits sixteen shared offering lines ~
pl6 respectively conducted over an input level converter stage ECL/E CL (for example of the type Siemens SH100-HITEl) and a serving line ttl. .tt8 conducted over an output level converter stage E CL/ECL (for example, contained in a 2-bit 12Q423C~
multiplexer cell of the type Siemens SH100-HMXAl (or, respectively, given inversion of the output signal, of the type SH100-HMXA2) is formed with two 4-bit multiplexer cells 151, 152...851, 852 respectively exhibiting two 4-bit multiplexers and a third 4-bit multiplexer cell 153...853 exhibiting a 4-bit multiplexer. As can be seen from FIG. 3, the third 4-bit multiplexer cell, just like the other two 4-bit multiplexer cells, can exhibit two respective 4-bit multiplexers of which only the one is then exploited. The controllable multiplexer cells can be formed by multiplexer cells SH100-HMX05 kept in so-called E2CL technology. The two 4-bit multiplexer cells .51 and .52 are driven in common with two control bits over two binary signal lines a, b, so that the four 4-bit multiplexers are respectively located in a specific through-connection status of four possible through-connection states. In a corresponding manner, the 4-bit multiplexer cell .53 is driven with two further control bits over two further binary signal lines c, _, so that the fifth 4-bit multiplexer is also respectively located in one specific through-connection state of full possible through-connection states.
As may be seen from FIG. 3, an additional transfer crosspoint can be provided at each crosspoint pyramid KPPl...
KPP8, the one switching segment of the additional transfer crosspoint being inserted in the serving line ttl...tt8 of the crosspoint pyramids XPPl...KPP8. As also indicated in FIG. 3, this transfer crosspoint can be formed by a 2-bit multiplexer cell 111...811, for example, by a 2-bit multi-plexer cell of the type Siemens SH100--HMXAl (or,respectively, given inversion of the output signal, of the type SH100-HMXA2). This 2-bit multiplexer cell 11 can be controlled by an additional control bit over an additional binary signal line e, so that it is respectively located in its one or its other through-connection state.
Without being illustrated in FIG. 3, the other offering terminal of the additional transfer crosspoint .11 can be connected to a serving line of a further crosspoint pyramid, the serving line being connected to an additional input z of the crosspoint pyramids KPP, wherewith a corresponding expansion of the switching matrix network to, for example, 32 offering lines is achieved. ~his expansion can be expanded in a corresponding manner given the further crosspoint pyramids to, for example, 48 offering lines (or, respectively, further multiples of 16).
As may also be seen from FIG. 3, the crosspoint pyramids can be divided into two groups for reducing the load per offering level converter stage (for example, of the type Siemens SH100-HIT~l), whereby the crosspoint pyramids KPPl...
KPP4 are charged with the non-inverted offering signals and the crosspoint pyramids KPP5...KPP8 are charged with the inverted offering signals, whereby the inversion is, in turn, canceled at the output of the serving level converter stage E2CL/ECL contained in the 2-bit multiplexer cell...811.
Moreover, as may likewise be seen from FIG. 3, the drive registers Regl...Reg4, Reg5...Reg8 belonging to the individual crosspoint pyramids KPPl..KPP4, KPP5...KPP8 can also be driven in a corresponding manner, the drive registers being illustrated in FIG. 3 below the crosspoint pyramids and from which the drive lines al,bl,cl,dl,el...a4,b4,c4,d4, e4; a5~ b5,c5,d5,e5...a8,b8,c8,d8,e8 lead to the respectively appertaining crosspoint pyramids. As already indicated in FIG. 3, the drive registers Reg can be respectively formed ~204230 with a 2-bit multiplexer cell (preferably of the type Siemens SH100-HMXOl) containing four 2-hit multiplexers respectively driven in pairs and with a 2-bit multiplexer cell (preferably of the type Siemens SH100-HMXA4) containing a 2-bit multi-plexer, whereby the individual multiplexers become a bistable circuit by way of respective feedback. As can further he seen from FIG. 3, the drive registers can, in part, such as the registers Regl...~eg4, then be driven with non-inverted signals and, in part, as the registers Reg5...Reg8, with inverted signals, whereby the inversion is then taken into consideration by a correspondingly-modified assignment of the offering lines pl...pl6 to the inputs of the controlled 4-bit multiplexer cells of the crosspoint pyramids KPR5...KPP8.
It is also indicated in FIG. 3 that the individual drive registers Reg and, therefore, the individual crosspoint pyramids KPP can be designationally driven with the assistance of a clock decoder TD likewise located on the LSI module. The clock decoder TD thereby comprises a demultiplexer of, prefer-ably of the type Siemens SH100-HDM81 which, as may be seen from FIG. 3, is charged with a 3-bit address AT, BT, CT of the respective register and, therefore, of the respective cross-point pyramid as well as with a clock T and, if necessary, with a chip designation signal ST.
Although I have described my invention by reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. I therefore intend to include within the patent warranted hereon all such changes and modifications as may reasonably and properly be included with-in the scope of my contribution to the art.
Field of the Invention The present invention relates to a broadband communication system having optical waveguide subscriber lines for digital communication signals, for example, 64 kbit/s digital telephone signals, picture screen text signals, 8 kbit/s control signals, 34 Mbit/s moving picture communication -signals, respectively transmitted between an exchange center and a subscriber station.
Description of the Prior Art In an optical waveguide broadband communication system, the subscriber lines can respectively exhibit a single optical waveguide exploited in both transmission direction or, on the other hand, two respective separate optical waveguides for the ~o directions of transmission. In the former case, television (TV) and/or audio broadband signals are transmitted over the optical waveguide from the exchange center to the subscriber station, but, given a prior state of wavelength multiplex technique, only control signals or relatively simple replies, given interactive services, can be transmitted in a return channel from the subscriber station to the exchange center. When, proceeding beyond that, 64 kbit/s digital signals (if necessary, a plurality of 8 kbit/s digital signals), for example, or digital telephony, picture screen text, facsimile and for signaling and synchronizing such narrow band communication services, are to be transmitted between the subscriber station and the switching center or, respectively, in the reverse direction, then two optical waveguides per subscriber termination can be provided, in particular, a separate optical waveguide for each direction of transmission NTZ, Vol. 32, No. 3, 1979, pp. 150-153), whereby video commun-ication signals for a picture telephone communication can, under certain conditions, also be conducted over the two optical waveguides.
Such a signal transmission over transmission direction-associated optical waveguides for the transmission in the direction to~ards the subscriber station requires a bundling of TV and, if necessary, stereo audio signals to be distributed in the frame~ork of uni.directional communication services, such as television and radio having telecommunication signals to be transmitted within the frame~ork of bidirectional communication services such. as, for example, telephony, telegraphy, data communication, and therefore, under certain condi.tions, entails a linkage of commun;cation services of different operators ~hich can be undesirable for legal reasons, for telecommunication policy reasons or for technical reasons as ~ell. In order to avoid this, as already specified in our Canadi.an application Serial No. 408,176 filed July 27, 1982, a broadband communication system having subscriber lines for T~ and/or stereo audio broadband signals exhibiting two respective optical ~aveguides and respectively extending be-tween an exchange center and a subscriber station for digital communication signals wh;ch are narro~ band in comparison thereto, in which broadhand signals are transmitted in multi-plex over the one optical waveguide from the exchange or, respectively, di~tribution center to the subscriber station and di.gital communication narro~ band signals, particularly 64 kbit/s digital signals, as well as program selection signals, are transmitted in multiplex over the other optical waveguide from the subscriber station to the exchange or, respectively, 12~4230 distribution center, can also be designed such that only the TV and/or stereo audio broadband signals are transmitted over one optical waveguide from the exchange or, respectively, distribution center to the subscriber station and all digital communication narrow band signals and, if necessary, bi-directional moving picture communication data signals as well, are transmitted over the other light waveguide between the exchange center and the subscriber station and vice-versa, whereby the digital communication signals of the two transmission directions can be transmitted over the other optical waveguide in the discrete time slot method. In such a broadband communication system, the TV and stereo audio program distribution, on the one hand, and the bidirectional narrow band digital communication and, under certain conditions, the picture telephone digital communication, on the other hand, can be realized independently of one another, as well as successively under certain conditions.
SUMMARY OF THE INVENTION
-A broadband communication system having optical waveguide subscriber lines, however, need not always also provide a transmission of TV and/or stereo audio signals to be distributed in the framework of unidirectional communication services such as television and radio but, rather, can also provide a transmission of telecommunication signals solely in the framework of bidirectional communication services such as telephony, telegraphy, data communication and moving picture communication and the object of the present invention, there-fore, is to iprovide a broadband communication system particularly suited for this purpose.
12()4Z30 The present invention relates to a broadband communication system having subscriber lines for broadband signals and, in contrast thereto, narrowband digital commun-ication signals, the subscriber lines each comprising an optical waveguide connected bet~een an exchange centre and a subscribe.r station, characterized in that digital communic-ation narrowband signals and bidirectional picture communic-ation digital signals of both transmission directions between the exchange centre and the subscriber station and vice-versa are transmitted in accordance with a discrete time slot method over a single optical waveguide forming a subscriber line.
In conjunction with the fact that the technology required for its realization already meets practical require-ments today, the invention offers the advantage that a decoupling of the signals of the t~o transmission directions, for example, by way of color filters or high-grade directional couplers is not necessary in the optical level but, rather, a simple (for example, 3 dB) coupler between the optical wave-guide, on the one hand, and an optical waveguide coming froma re~pective electro-optical transducer or, respectively, an optical ~aveguide leading to the respective opto-electrical transducer, on the other h.and, adequately suffices.
According to a further feature of the invention, the digi.tal communication signals of a res.pective transmission direction can be advantageously transmitted over the optical ~avegui.de bundled in accordance with time-division multiplex techniques.
~2()4230 BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention, its organization, cons~ruction and operation will be best understood from the following detailed description, taken in conjunction with the accompanying drawings, on which:
FIG. 1 is a schematic diagram of an exemplary embodiment of a broadband communication system constructed in accordance with the present invention; and FIG. 2 is a schematic representation illustrating the chronological sequence of a digital transmission in accordance with the discrete time slot method for a broad-band communication system of the type illustrated in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
-FIG. 1 of the drawing schematically illustrates an exemplary embodiment of a broadband communication system according to the invention in a scope necessary for an under-standing of the invention. In this broadband communication system, a subscriber station Tln St is connected over a subscriber llne Al exhibiting an optical waveguide L formed, for example, by a gradient fiber having a 50 ~ core diameter and a 150 ~ ~acket diameter, to the appertaining exchange center VSt, whereby it is indicated in FIG. 1 that the subscriber station Tln St can be equipped for digital telephony, facsimile service, picture screen text, push-button dialing and display indication and can also be equipped, with a video communication system VKA having a camera and picture screen device, for bidirectional moving picture com~unication (picture telephony).
All digital communication narrow band signals, as well as bidirectional picture communication digital signals, are transmitted from the exchange center VSt to the sub-scriber station Tln St and in the reverse direction, from the subscriber station Tln St to the exchange center VSt, over the optical waveguide L. Thereby, for example, in the manner known from the Australian Letters Patent 354,527 or, respectively, United States Letters Patent 4,025,725, digital telephone signals (for example 64 kbit/s), facsimile signals and control signals (for example 8 kbit/s) as well as picture screen text (Btx) signals switched through in the exchange lQ center VSt over a narrow band switching matrix network KFs are combined ~ith picture communication signals switched through over a picture communication switching matrix network KFV, like~ise controlled by the exchange control Vs to form a multiplex signal to be transmitted to the subscriber station Tln St, for example, an 8 Mbit/s or a 34 Mbit/s time-division multiplex signal. A multiplex signal, particularly a time-division multiplex signal, proceeding in the reverse trans-mission direction from the subscriber station Tln St to the exchange center VSt i5 fanned out in the corresponding de-multiplexer DEXv into the corresponding individual signals,for example, digital telephone signals (for example 64 kbit/s) and facsimile ~ignal, control signal (for example 8bit/s) as ~ell as picture screen text signals s~itched through over the narro~ ~and s~itching net~ork KFs and digital picture tele-communication signal s~itched through over the picture communi.cation s~itching matrix net~ork KFB.
~ corresponding si.gnal bundling or, respecti.vely, debundling, corresponds in the subscriber station Tln St, respectively in the reverse transmission direction, to ~hich 3Q end a corresponding multiplexer MULt and a corresponding ~ .
423~
demultiplexer DEXt are provided.
The multiplexer MUL and the demultiplexer DEX can for example, be realized with commercially available multiplex devices such as the Siemens ZD1000 Cl and ZD1000 E10 for a 64 kbit/s multiplex signal and a commercially available multiplex device such as the Siemens DSE 64 k/2 for the combination of 64 kbit/s signals into a 2,048 Mbit/s multiplex signal, as well as with a commercially available multiplex device such as the Siemens DSMX2/8 (given an 8 Mbit/s digital signal) and, in addition, the DSMX8/34 (given a 34 Mbit/s digital signal).
As likewise indicated in FIG~ 1, the telephone terminal is connected in the transmission direction to a corresponding input of the multiplexer MULt by way of an analog/digital converter a/d and is connected in the receiving direction to a corresponding output of the demultiplexer DEXt via a digital/analog converter da. The video communication system VKA is connected in the transmission direction to a corresponding input of the multiplexer MULt via an analog/
digital converter D/A and is connected in the receiving direction to a corresponding output of the demultiplexer DEXt via a digital/analog converter D/A.
The electrical terminal of an electro-optical transducer e/o is connected in the exchange center VSt to the output of the subscriber-associated multiplexer MULv. The input of the demultiplexer DEXv provided in the exchange center VSt is connected to the output of an opto-electrical transducer o/e. The optical terminals of these two transducers are connected to the optical waveguide L via a glass fiber directional coupler RKv. In a corresponding manner, the lZ~4230 optical waveguide L is connected in the subscriber station Tln St over a glass fiber directional coupler RKt to the optical output of an electro-optical transducer e/o and the optical input of an opto-electrical transducer o/e, whereby the electrical input of the electro-optical transducer e/o is connected to the output of the multiplexer MULt and the electrical output of the opto-electrical transducer o/e is connected to the input of the demultiplexer DEXt. The individual narrow band communication terminals or,respectively, subterminals as well as the video communication system VKA
are then connected to the inputs of the multiplexer MULt or, respectively, to the outputs of the demultiplexer DEXt, without the necessity of further explanation here.
The glass fiber directional couplers RK, which like-wise need not be explained in greater detail here since glass fiber directional couplers are known p r se, for example from the publication Nachrichten Elektronik (1979) 1,18), are not subjected to any special requirements concerning the decoupling of the multiplex signals of the two transmission directions from one another when, as is likewise indicated in FIG. 1, the multiplex signals of the two transmission directions are transmitted over the optical waveguide L in accordance with the discrete time slot technique. In the broadband communi-cation system illustrated in FIG.l, provided in the exchange center DSt for that purpose between the multiplexer MULv or, respectively, the demultiplexer DEXv and the electro-optical transducer e/o or, respectively, the opto-electrical trans-ducer o/e is, for example, a buffer circuit Zv to be realized with a shift register. In a corresponding manner, a corre-sponding discrete time slot buffer circuit Zt is provided in the subscriber station Tln St between the multiplexer MULt and 121~)4Z30 the demultiplexer DEXt, on the one hand, and the electro-optical transducer e/o and the opto-electrical transducer o/e on the other hand.
The displacement of the actual direction separation from the optical level into the electrical (and digital) level therefore effected has the advantage that the discrete time-slot control circuits Zv, Zt may be realized in traditional integrated circuit (IC) technology (for example, with shift registers). The fact connected with the employment of the discrete time-slot method that the bit repetition rate in the signal bursts on the line amounts to a multiple of the useful bit rate can advantageously remain out of consideration given use on the optical waveguide L because, on the one hand, no high-frequency unwanted radiation occurs here and, on the other hand, the line attenuation of the optical waveguide does not rise with an increasing bit rate, i.e. the range thereof is not influenced as given a copper (Cu) line. It is there-fore advantageous when determining the parameters for the discrete time-slot transmission of, for example, burst length and burst pause, to base these on the maximally-possible range given signal transmission over an optical waveguide.
An example of the chronological sequence of a corresponding burst transmission is illustrated in FIG. 2.
According to this example, a maximum signal transit time of 40 ~s per transmission direction is available for an 80 ~s long digital signal block (burst), this corresponding to an optical waveguide length (range) of approximately 8 km. Within each burst, for example, 8 kbit/s can be respectively trans-mitted with a transmission rate of, for example, 100 Mbit/s.
In conclusion, it should also be pointed out that 120423~) the image switching matrix network KVB indicated in FIG. 1 can comprise crosspoint circuits realized in ECL technology which are formed by controllable multiplexers interconnected to form multi-stage crosspoint pyramids, as has already been described in the German Letters Patent 3,204,900.5, Electronics, March 24, 1982, pp. 41E, 42E.
According to FIG. 3, a broadband switching network having crosspoint circuits realized in ECL technology is provided for switching or, respectively, distributing communication signals, the crosspoint circuits being formed by controllable multiplexers 151, 152, 153...851, 852, 853, whereby the controllable multiplexers are interconnected to form multi-stage crosspoint pyramids KPPl...KPP8 respectively comprising a serving line ttl....tt8 and a plurality of shared offering lines pl...pl6. Thereby, eight crosspoint pyramids KPPl...KPP4, KPP5...KPP8 respectively comprising an individual serving line ttl...tt4, tt5...tt8 and sixteen shared offering lines ~...pl6 are illustrated or,respectively, indicated in FIG. 3. These, combined on a large scale integration (LSI) module (preferably on a gate array of the E2CL-100 master/module family of Siemens SH100 (described, for example, in the Siemens Data Sheets integrated circuits-SH100 Family-Design Kit-Cell Library, and in the Siemens publication Gate Arrays-Masken-Programmierbare Logikschaltungen, 1981 Edition, Order No. No. B/2363), form a broadband switching matrix module 16/8. Each crosspoint pyramid KPPl...KPP8 which, in the example, exhibits sixteen shared offering lines ~
pl6 respectively conducted over an input level converter stage ECL/E CL (for example of the type Siemens SH100-HITEl) and a serving line ttl. .tt8 conducted over an output level converter stage E CL/ECL (for example, contained in a 2-bit 12Q423C~
multiplexer cell of the type Siemens SH100-HMXAl (or, respectively, given inversion of the output signal, of the type SH100-HMXA2) is formed with two 4-bit multiplexer cells 151, 152...851, 852 respectively exhibiting two 4-bit multiplexers and a third 4-bit multiplexer cell 153...853 exhibiting a 4-bit multiplexer. As can be seen from FIG. 3, the third 4-bit multiplexer cell, just like the other two 4-bit multiplexer cells, can exhibit two respective 4-bit multiplexers of which only the one is then exploited. The controllable multiplexer cells can be formed by multiplexer cells SH100-HMX05 kept in so-called E2CL technology. The two 4-bit multiplexer cells .51 and .52 are driven in common with two control bits over two binary signal lines a, b, so that the four 4-bit multiplexers are respectively located in a specific through-connection status of four possible through-connection states. In a corresponding manner, the 4-bit multiplexer cell .53 is driven with two further control bits over two further binary signal lines c, _, so that the fifth 4-bit multiplexer is also respectively located in one specific through-connection state of full possible through-connection states.
As may be seen from FIG. 3, an additional transfer crosspoint can be provided at each crosspoint pyramid KPPl...
KPP8, the one switching segment of the additional transfer crosspoint being inserted in the serving line ttl...tt8 of the crosspoint pyramids XPPl...KPP8. As also indicated in FIG. 3, this transfer crosspoint can be formed by a 2-bit multiplexer cell 111...811, for example, by a 2-bit multi-plexer cell of the type Siemens SH100--HMXAl (or,respectively, given inversion of the output signal, of the type SH100-HMXA2). This 2-bit multiplexer cell 11 can be controlled by an additional control bit over an additional binary signal line e, so that it is respectively located in its one or its other through-connection state.
Without being illustrated in FIG. 3, the other offering terminal of the additional transfer crosspoint .11 can be connected to a serving line of a further crosspoint pyramid, the serving line being connected to an additional input z of the crosspoint pyramids KPP, wherewith a corresponding expansion of the switching matrix network to, for example, 32 offering lines is achieved. ~his expansion can be expanded in a corresponding manner given the further crosspoint pyramids to, for example, 48 offering lines (or, respectively, further multiples of 16).
As may also be seen from FIG. 3, the crosspoint pyramids can be divided into two groups for reducing the load per offering level converter stage (for example, of the type Siemens SH100-HIT~l), whereby the crosspoint pyramids KPPl...
KPP4 are charged with the non-inverted offering signals and the crosspoint pyramids KPP5...KPP8 are charged with the inverted offering signals, whereby the inversion is, in turn, canceled at the output of the serving level converter stage E2CL/ECL contained in the 2-bit multiplexer cell...811.
Moreover, as may likewise be seen from FIG. 3, the drive registers Regl...Reg4, Reg5...Reg8 belonging to the individual crosspoint pyramids KPPl..KPP4, KPP5...KPP8 can also be driven in a corresponding manner, the drive registers being illustrated in FIG. 3 below the crosspoint pyramids and from which the drive lines al,bl,cl,dl,el...a4,b4,c4,d4, e4; a5~ b5,c5,d5,e5...a8,b8,c8,d8,e8 lead to the respectively appertaining crosspoint pyramids. As already indicated in FIG. 3, the drive registers Reg can be respectively formed ~204230 with a 2-bit multiplexer cell (preferably of the type Siemens SH100-HMXOl) containing four 2-hit multiplexers respectively driven in pairs and with a 2-bit multiplexer cell (preferably of the type Siemens SH100-HMXA4) containing a 2-bit multi-plexer, whereby the individual multiplexers become a bistable circuit by way of respective feedback. As can further he seen from FIG. 3, the drive registers can, in part, such as the registers Regl...~eg4, then be driven with non-inverted signals and, in part, as the registers Reg5...Reg8, with inverted signals, whereby the inversion is then taken into consideration by a correspondingly-modified assignment of the offering lines pl...pl6 to the inputs of the controlled 4-bit multiplexer cells of the crosspoint pyramids KPR5...KPP8.
It is also indicated in FIG. 3 that the individual drive registers Reg and, therefore, the individual crosspoint pyramids KPP can be designationally driven with the assistance of a clock decoder TD likewise located on the LSI module. The clock decoder TD thereby comprises a demultiplexer of, prefer-ably of the type Siemens SH100-HDM81 which, as may be seen from FIG. 3, is charged with a 3-bit address AT, BT, CT of the respective register and, therefore, of the respective cross-point pyramid as well as with a clock T and, if necessary, with a chip designation signal ST.
Although I have described my invention by reference to particular illustrative embodiments thereof, many changes and modifications of the invention may become apparent to those skilled in the art without departing from the spirit and scope of the invention. I therefore intend to include within the patent warranted hereon all such changes and modifications as may reasonably and properly be included with-in the scope of my contribution to the art.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A broadband communication system having sub-scriber lines for broadband signals and, in contrast thereto, narrowband digital communication signals, the subscriber lines each comprising an optical waveguide connected between an exchange centre and a subscriber station, characterized in that digital communication narrowband signals and bidirectional picture communication digital signals of both transmission directions between the exchange centre and the subscriber station and vice-versa are transmitted in accordance with a discrete time slot method over a single optical waveguide forming a subscriber line.
2. A broadband communication system according to claim 1, characterized in that the digital communication signals of a respective transmission direction are transmitted over the optical waveguide using time division multiplexing.
3. A broadband communication system according to claim 1, characterized in that the narrowband digital commun-ication signals are 64 kbit/s digital signals.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DEP3218261.9 | 1982-05-14 | ||
DE19823218261 DE3218261A1 (en) | 1982-05-14 | 1982-05-14 | BROAD COMMUNICATION SYSTEM |
Publications (1)
Publication Number | Publication Date |
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CA1204230A true CA1204230A (en) | 1986-05-06 |
Family
ID=6163651
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CA000427986A Expired CA1204230A (en) | 1982-05-14 | 1983-05-12 | Broadband communication system |
Country Status (5)
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EP (1) | EP0094096B1 (en) |
JP (1) | JPS58206246A (en) |
AT (1) | ATE22636T1 (en) |
CA (1) | CA1204230A (en) |
DE (2) | DE3218261A1 (en) |
Cited By (7)
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US5408462A (en) * | 1993-10-07 | 1995-04-18 | Adc Telecommunications, Inc. | Protection switching apparatus and method |
US5453737A (en) * | 1993-10-08 | 1995-09-26 | Adc Telecommunications, Inc. | Control and communications apparatus |
US5519830A (en) * | 1993-06-10 | 1996-05-21 | Adc Telecommunications, Inc. | Point-to-multipoint performance monitoring and failure isolation system |
US5528579A (en) * | 1993-06-11 | 1996-06-18 | Adc Telecommunications, Inc. | Added bit signalling in a telecommunications system |
US6334219B1 (en) | 1994-09-26 | 2001-12-25 | Adc Telecommunications Inc. | Channel selection for a hybrid fiber coax network |
USRE41771E1 (en) | 1995-02-06 | 2010-09-28 | Adc Telecommunications, Inc. | System for multiple use subchannels |
USRE42236E1 (en) | 1995-02-06 | 2011-03-22 | Adc Telecommunications, Inc. | Multiuse subcarriers in multipoint-to-point communication using orthogonal frequency division multiplexing |
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ATE60478T1 (en) * | 1984-08-10 | 1991-02-15 | Siemens Ag | INTEGRATED SERVICES TELECOMMUNICATIONS SYSTEM FOR NARROW BAND SERVICES. |
JPS61121627A (en) * | 1984-11-19 | 1986-06-09 | Hitachi Ltd | Terminal connecting device by optical transmission |
US4675861A (en) * | 1984-11-28 | 1987-06-23 | Adc Telecommunications, Inc. | Fiber optic multiplexer |
DE3713933C2 (en) * | 1987-04-25 | 1994-11-10 | Rheydt Kabelwerk Ag | Digital transmission system |
GB2215943A (en) * | 1988-03-19 | 1989-09-27 | Stc Plc | Multiplexer |
US5253935A (en) * | 1990-05-04 | 1993-10-19 | Raychem Corporation | Couples for terminating optical fiber ends |
FI86016C (en) * | 1990-06-12 | 1992-06-25 | Nokia Oy Ab | OPTISKT OEVERFOERINGSSYSTEM OCH -FOERFARANDE. |
JP3457338B2 (en) * | 1992-03-30 | 2003-10-14 | 株式会社日立製作所 | Videophone and videoconferencing equipment |
DE19512193A1 (en) * | 1995-03-31 | 1996-10-10 | Siemens Ag | Crossed ping-pong method for passive optical networks |
DE10126339A1 (en) * | 2001-05-30 | 2003-03-20 | Siemens Ag | Bus system operating method for building automation applications has data fed along bus line divided into time slots |
RU2521045C1 (en) * | 2012-12-27 | 2014-06-27 | Сергей Николаевич Сергеев | Method of setting up duplex links in one fibre using optical signals operating in opposite directions and having same carrier wavelength with retroreflection control |
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IT1093493B (en) * | 1978-03-23 | 1985-07-19 | Honeywell Inf Systems | BIDIRECTIONAL TRANSMISSION CIRCUIT OF INTERLOCKED SIGNALS |
CA1119254A (en) * | 1978-04-18 | 1982-03-02 | Joseph H. Greenberg | Fiber optics high speed modem |
EP0012979B1 (en) * | 1978-12-27 | 1983-03-23 | Siemens Aktiengesellschaft | Method for the transmission of several signals via a lightwave guide link, in particular between an exchange and a subscriber's connection |
DE2922418C2 (en) * | 1979-06-01 | 1981-12-03 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Integrated services message transmission and switching system for sound, images and data |
DE3044605A1 (en) * | 1980-11-27 | 1982-06-24 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | "SERVICE-INTEGRATED DIGITAL TRANSMISSION SYSTEM" |
EP0071232B1 (en) * | 1981-07-28 | 1985-11-13 | Siemens Aktiengesellschaft | Broad-band communication system |
-
1982
- 1982-05-14 DE DE19823218261 patent/DE3218261A1/en not_active Withdrawn
-
1983
- 1983-05-11 DE DE8383104676T patent/DE3366548D1/en not_active Expired
- 1983-05-11 AT AT83104676T patent/ATE22636T1/en not_active IP Right Cessation
- 1983-05-11 EP EP83104676A patent/EP0094096B1/en not_active Expired
- 1983-05-11 JP JP58081024A patent/JPS58206246A/en active Pending
- 1983-05-12 CA CA000427986A patent/CA1204230A/en not_active Expired
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Also Published As
Publication number | Publication date |
---|---|
EP0094096B1 (en) | 1986-10-01 |
JPS58206246A (en) | 1983-12-01 |
EP0094096A1 (en) | 1983-11-16 |
DE3218261A1 (en) | 1983-12-22 |
ATE22636T1 (en) | 1986-10-15 |
DE3366548D1 (en) | 1986-11-06 |
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