IL43250A

IL43250A - A wide-band communications system

Info

Publication number: IL43250A
Application number: IL43250A
Authority: IL
Original assignee: Siemens Ag
Priority date: 1972-09-22
Filing date: 1973-09-18
Publication date: 1976-07-30
Also published as: DE2246488B2; DE2246488A1; BE805173A; IL43250A0; GB1439650A; FR2200705A1; AT349072B; ATA787373A; CH566683A5; FR2200705B1; JPS4994218A; NL7313082A

Claims

WHAT WE CLAIM IS :-

1. A wide band communica ions system for effecting transmission of a plurality of radio and video' transmissions, video-telephony, individual data transmission and/or other communications services, in which the transmissio between a central unit and the subscribers takes place firstly via cables or radio relay links and secondly via party cable installations, wherein the wide band communications network is divided into four levels namely Ά· long distance level extending between a programme centre and a regional central unit, a toll traffic level extending between the regional central unit and a transfer point, a local network level extending between the transfer point and a branch point and a subscriber level extending between the branch point, via a distributor of a party cable installation, to a subscriber, wherein the long distance traffic is effected via a coaxial long distance connection and/or via a radio relay link .using an appropriate type of modulation, wherein the conversion from the type of modulation used on the long distance level to the type of modulation for subscriber devices is carried out in the regional central unit, wherein at the local level there is employed a combined cable which contains both a wide band coaxial cable and also additional symmetrical wires, wherein repeaters in the local network level are remote-fed and remote-monitored from the transfer point, wherein the conversion of the television and sound-broadcast channels from the toll traffic level into the local network level takes place via an intermediate frequency state, and the audio-frequencies in the local network are transmitted in the UKW original state (87.5 - 104 MHz), wherein in the local network, band III channels are transmitted in television-orientated modulation form and in the original state, and further television channels are transmitted in receiver-orientated modulation form but in the frequency range from 4 MHz to 300 MHz, wherein in the branch point non-receiver-orientated signals are rendered receiver-orientated and are brought into the IV/V bands, wherein all communications and distribution services are commonly conducted between the . programme centre and the distributor, whereas they are conducted separately between the distributor and the subscriber.

2. A system as claimed in Claim 1, wherein the transmission of six television channels in the toll traffic level is carried out in a frequency band from .4 MHz to 60 MHz, and wherein the conversion into the local network level is carried out in an intermediate frequency state of 71 - 78 MHz.

3. A system as claimed in Claim 1 or Claim 2, wherein the local network level employs substantially constant current d.c. remote-feed for the repeaters, and wherein the substantially current remote feed circuit comprises two additional current supply wires in the cable.

4. A system as claimed in Claim 3, wherein in the local network level a plurality of repeaters are fed commonly via a converter. '

5. A syfcem as claimed in Claim 3, wherein in the local network level a plurality of converters are connected in series and are effective such that at .their secondary end they each emit a substantially constant voltage independeifcly of the number of repeaters being fed, and wherein at their other end they absorb a substantially constant current from the remote feed circuit.

6. A system as claimed in any one of the preceding Claims, wherein in the local network level, a combined cable with at least two coaxial tubes is employed, one tube being used exclusively for the distributed services, and the second tube being Used, for bi-directional traffic.

7. A system as claimed in any one of the preceding Claims, wherein the symmetrical wires additionally employed in the local network level are used to accommodate the wide band services, and are provided in the form of supplementary wires to the coaxial cable.

8. A system as claimed in any one of Claims 1 to 6, wherein the additional symmetrical wires are commonly conducted within the combined cable in a separate cable.

9. A system as claimed in any one of the preceding Claims wherein concentrators are provided between the transfer point and the distributors. • 10..

10. A system as claimed in any one of the preceding Claim wherein the individual traffic is conducted into the wide band transmission network via converters, and wherein \vith increasing traffic, the conversion is advanced in stages to points in the direction towards the distributor terminal.

11. A. system as claimed in any one of the pre ceding.. Claim wherein for the remote feed of the repeaters in the symmetrical pairs in the local network, individual system feed takes place e.g. via phantom circuits.

12. Wide band communications system as claimed in any one of the .preceding Claims, wherein at least some of the repeaters are rem'otely monitored.

13. A system as claimed in any one. of the preceding Claims, wherein the distributors are monitored.

14. A system as claimed in any one of the preceding Claims, wherein the distributors are disposed in such positions that the cables, extending between them and the subscribers do not cross over any public roads.

15. A system as claimed in any one of the preceding Claims, wherein intermediate repeaters are disposed at said branch points. '.

16.; A system as claimed in any one of the preceding Claims, wherein at the boundary lines to adjacent exchange areas, as large as 'possible a number of cable terminal point are available.

17. A wide band communications system substantially a herein described with referece to the drawings. For fhe licanis DR. REIN! COH AND PARTNERS B y :