CA1156349A - Buffer memory dispersion type video/audio transmission system with spatially and timewise divided inter-office junction lines - Google Patents

Buffer memory dispersion type video/audio transmission system with spatially and timewise divided inter-office junction lines

Info

Publication number
CA1156349A
CA1156349A CA000340229A CA340229A CA1156349A CA 1156349 A CA1156349 A CA 1156349A CA 000340229 A CA000340229 A CA 000340229A CA 340229 A CA340229 A CA 340229A CA 1156349 A CA1156349 A CA 1156349A
Authority
CA
Canada
Prior art keywords
video
audio
center
unit
information
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
Application number
CA000340229A
Other languages
French (fr)
Inventor
Akira Yabiki
Norio Imanishi
Yoji Shibata
Wataru Kosuge
Nobumichi Yukawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Nippon Telegraph and Telephone Corp
Original Assignee
Hitachi Ltd
Nippon Telegraph and Telephone Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd, Nippon Telegraph and Telephone Corp filed Critical Hitachi Ltd
Application granted granted Critical
Publication of CA1156349A publication Critical patent/CA1156349A/en
Expired legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04HBROADCAST COMMUNICATION
    • H04H20/00Arrangements for broadcast or for distribution combined with broadcast
    • H04H20/65Arrangements characterised by transmission systems for broadcast
    • H04H20/76Wired systems
    • H04H20/77Wired systems using carrier waves
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04MTELEPHONIC COMMUNICATION
    • H04M11/00Telephonic communication systems specially adapted for combination with other electrical systems
    • H04M11/08Telephonic communication systems specially adapted for combination with other electrical systems specially adapted for optional reception of entertainment or informative matter
    • H04M11/085Telephonic communication systems specially adapted for combination with other electrical systems specially adapted for optional reception of entertainment or informative matter using a television receiver, e.g. viewdata system
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04QSELECTING
    • H04Q11/00Selecting arrangements for multiplex systems
    • H04Q11/04Selecting arrangements for multiplex systems for time-division multiplexing
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S379/00Telephonic communications
    • Y10S379/908Multimedia

Abstract

ABSTRACT OF THE DISCLOSURE
A video/audio transmission system for sending video and audio information from the video and audio files of a center to a subscriber through a subscriber's junction line is dis-closed in which at least one subcenter is disposed near to the subscriber to reduce the number of repeaters arranged on the subscriber's junction line. The subcenters can include a video/audio buffer memory, and exchange and other related cir-cuits. The transmission lines for sending the video and audio information from the center to the subcenter are spatially di-vided into a plurality of groups in accordance with the sort of the video and audio information being sent, and further the information is time-divisionally transmitted at each group.

Description

The present invention relates to an information service system for providing multiplex information such as picture images and data in which the telephone communication system and the television broadcasting system, which are among the basic media having a nationwide communication network, are combined with each other. More particularly, the present in-vention relates to a buffer memory dispersion type video/audio transmission system with spatially and timewise divided inter-office junction lines which is a video/audio transmission system provided with sub-centers each including buffer memDries and with spatially and timewise divided transmission lines be-tween the center and the sub-centers.
As information is increased in variety and becomes highly-advanced, many countries have spent a great effort to put to practical use an information service system which em-ploys a wide-band, large-capacity communication network and can provide multiplex information such as pictures and data.
For example, the multi-purpose utilization of the broadcasting and telephone networks, each of which provides a basic medium of communication, has been studied. As for the utilization of broadcasting waves, in addition to the charac-ter multiplex broadcasting system (TELETEXT) which has been put to practical use in England, the audio multiplex broad-casting system and a character multiplex broadcasting system have been tested in many countries for the purpose of practi-cal use. Further, as fox the utilization of the telephone network, the Post Of`fice in England has conducted an examina-' tion of an information service system (PRESSTEL) for thepurpose of practical use, and this system has been enjoying favorable evaluation.
Attempts heretofore made at the multi-purpose utili-zation of the broadcasting and telephone networks may beclassified as follows: 1) Effective utilization of the exis-ting communications networks, 2) Establishment of local, small-scale information service systems for public, and 3) Prevalence of information service systems for exclusive use.
More particularIy, there is provided:
A buffer memory dispersion type video/audio transmis-sion system comprising:
a center comprising a group of audio files for storing audio information, a group of video files for storing video information, and a central processing and controlling unit for executing a controlling operation in response to an informa-tion request received at said center from a subscriber terminal unit to fetch specific information from said audio and video file groups and transmit the specific information to the sub-scriber terminal unit; and a plurality of subcenters coupled between said center and said subscriber terminal unit, said subcenters being coupled to said ¢enter through a time-division highway cable, each of said subcenters comprising:
video and audio buffer memories for temporarily storing the specific video and audio information which is transferred from said center through said time division data highway; and ~j!` 2 ... ~ .

.

an exchange connected to the subscriber terminal unit by a much shorter length of cable than a length of the iime-division highway cable connecting said subcenter to said center to thereby reduce the distance between the subscriber terminal unit and the exchange, said exchange including means coupled to said buffer memories for sending video and audio information stored in said buffer memories to said subscriber terminal unit.
Certain features describ~d in the disclosure of this invention are not claimed therein but are cla;~P~ in the ap-plicants' copending application Serial No. 340,230.
The objects, features and advantages of the present invention will become apparent from the following detailed description of a preferred embodiment thereof taken in conjunc-tlon with the accompanying drawings, in which:
Fig. 1 is a block diagram showing a conventional video/audio transmission network;
Fig. 2 is a block diagram showing one embodiment of a vldeo/audio transmission network according to the present in-
2~ vention;
Fig. 3 shows a detailed circuit arrangement of anotherembodiment of a video/audio transmission network including one sub-center according to the present invention;
Fig. 4 is a flow chart for explaining a service re-questing procedure in the case where a subscriber terminalconnected to a center requests a stationary picture to the center; and
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Fig. 5 is a flow chart for explaining a service re-questing procedure in the case where a subscriber terminal connected to a sub-center requests a stationary picture to a center.
According to the conventional center-to-end type video/
audio communication system which has been put to practical use, a video/audio transmission network has such a circuit arrangement as shown in Fig. l of the accompanying drawings.
That is, in a center 4 are installed a video/audio file l, a video/audio buffer memory 2 and an exchange 3. Further, the center 4 is connected to each of subscriber terminals 7 through a junction line (existing telephone line 5) which in-cludes a plurality of repeaters 6. Accordingly, when the dis-tance between the center 4 and the subscriber terminal 7 is made long, the number of repeaters 6, which must be provided at intervals of about 500 meters, is increased, and therefore the transmission network becomes expensive.
An object of the present invention is to provide a video/audio transmission system which can overcome the draw-backs of the conventional system and is low in cost.
In order to attain the above object, in a video/audiotransmission system according to the present invention, the buffer memories, the exchanges and the like, which have been provided within the center in the conventional system, are moved into sub-centers which are placed near to the subscriber terminals, in order to reduce the length of the subscribers ~, .

junction line for connecting the exchange to the subscriber terminal. Since the system includes a large num~er of junc-tion lines, the decrease in length of each junction line can reduce the number of repeaters required, and therefore can re-duce the cost of the system to a considerable degree.
Further, it is another object of the present inven-tion to provide a video/audio transmission system in which the number of transmission lines for interconnecting the center to the sub-centers and the number of repeaters are both reduced in a large degree, and besides a video signal and an audio signal are respectively transmitted by a separate trans-mission line in order to facilitate the maintenance and sur-veillance of the system.
The embodiment of the present invention shown in Fig.
2 will be explained below in detail. Referring to Fig. 2, a video/audio file l is provided in a center 4, and each of sub-centers 8 includes a buffer memory 2 and an exchange 3.
Various signals are transmitted from the center 4 to each sub-center 8 by a plurality of inter-office junction lines 9 in a time/space divisional fashion. For example, the inter-office junction lines are divided into two channels 9a and 9b, one of which transmits a luminance signal and a superim-posing signal in a time-divisional fashion and the other chan-nel transmits a chrominance signal and an audio signal in a time-divisional fashion.

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Since the sub-center 8 is placed near to a subscriber terminal 7, a subscriber's junction line 5 is short in length.
The number of repeaters included in the whole system is pro-portional to the length of the subscriber's junction line which is large in number. Accordingly, the embodiment shown in Fig. 2 includes a small number of repeaters and is low in cost.
Fig. 3 shows a detailed circuit arrangement of the embodiment shown in Fig. 2. In Fig. 3, reference numeral 10 denotes a central processing unit 10 for controlling the sys-tem, and 11 a connection matching unit for connecting and matching the central processing unit 10 to a video/audio file unit 1. The video/audio file unit 1 is made up of a video file group for stationary pictures, an audio file group and a video file group for motion pictures. The video file group:
for stationary pictures includes a microfilm sear¢h unit la, a digital pattern file unit lb, a digital picture file unit lc and a command-type pattern/character generator ld. The audio file group includes an audio response unit le, a PARCOR-type audio per picture file unit lf, a digital audio file unitlg and a composite audio file unit lh. The video file group for motion pictures includes a random access motion picture file unit li and a talking motion picture file unit lj. The video file group for stationary pictures is connected to a frame memory 13 through a video distributingJcoupling unit 12.

. . , . : .' ' . ' The audio file group is connected to an audio output unit 17 through an audio changeover unit 15a. Both the frame memory 13 and the random access motion picture file unit li are con-nected to a video output unit lb through a video changeover unit 14. Further, the random access motion picture file unit li and the talking motion picture file unit lj are both con-nected directly to the video output unit 16. The video output unit 16 and the audio output unit 17 are both connected to a video/audio signal combining unit 18 through a six-wire sys-tem exchange 3, and then connected to a subscriber junctionline 5. Further, the video file group for stationary pictures and the random access motion picutre file unit li are connec-ted to a stationary picture multiplex transmitter 19, and the audio file group is connected to an audio changeover unit 15b.
The center 4 having such a construction as above is connected not only to the sub-centers but also to a subscriber terminal 7a which is placed relatively near to the center. In more detail, the terminal 7a is.connected to the exchange 3 of ~ the center 4 through the video/audio signal combining unit 18, the subscriber's junction line 5 and a repeater 6, but a sub-scriber terminal 7b which is located far from the center 4, is connected to the center 4 through the sub-center 8.
The sub-center 8 is connected to the center 4 in the following manner: a stationary picture multiplex receiver 20 of the sub-center 8 is connected to the stationary picture multiplex transmitter 19 by means of a statioN~y picture multiplex transmission line 21, a composite-stationary-picture/motion-.. . .
.. . .............................. - . .... .
.

1~56349 picture line 22 and an audio line for composite stationary pictures and motion pictures 23, an audio changeover/output unit 24 of the sub-center 8 is connected to the audio change-over unit 15b by an audio line for stationary picutres 25, the audio changeover/output unit 25 is further connected to the video output unit 16 by a talking motion picture line 26, and a sub-center monitoring/controlling unit 27 of the sub-center 8 is connected to the central processing unit 10 by a data line 29.
The center 4 having such a cons~uction as above is con-nected not only to the sub-centers but also to a subscriber terminal 7a which is placed relatively near to the center.
Tn more detail, the terminal 7a is connected to the exchange 3 of the center 4 through the video/audio signal combining unit 18, the subscriber's junction line 5 and a repeater 6, but a subscriber terminal 7b which is located far from the center 4 is connected to the center 4 through the sub-center 8.
Further, the sub-center 8 has the circuit construction , as described below. The stationary picture multiplex receiver 20 ls connected to an audio changeover/output unit 24 and a video/audio buffer memory 2, both of which are connected to a video/audio signal combining and outputting unit 28. The sub-center monitsring/controlling unit 27 is connected through a control switch 40 to a video exchange 3a for changing over video receivers and to a telephone exchange 3b for changing over push-phones or key-boards. Both of the audio changeover/
output unit 24 and the video/audio signal combining and out-; ,:

.

putting unit 28 are connected to the video exchange 3a. In-cidentally, reference numeral 30 designates a center/sub-center monitoring and controlling unit.
Next, explanation will be made on a service re~uesting S procedure in the case where the subscriber terminal requires an information service from the video/audio file.
In the subscriber terminal 7a which is located near to the center 4, the power source of the television receiver 73 is first checked, as is shown in Fig. 4. The receiver 73 which has been turned off, is turned on, and an idle channel is selected. Next, the key-board is turned on, or the push-phone is put in the off-hook state, and the center 4 is called through dialing. In the subscriber terminal, a desired sta-tionary picture is selected by means of the push-button or the key-board when the subscriber terminal receives a dial tone which the center 4 transmits after the detection of calling.
In the exchange 3, the presence or absence of an idle trunk is detected. When the idle trunk is absent, a busy tone is sent to the subscriber terminal, but when the idle trunk is pre-sent, it is judged whether the service is stopped or not.When the service is stopped, a talking message for reporting the stoppage of service is sent to the subscriber terminal.
When the service is not stopped, a predetermined circuit con-nection is conducted. That is, in the center 4, a title (or index) for file information is sent out after the detection of an incoming signal, and it is checked by the subscriber terminal, and then the file information required or requested by the subscriber terminal can be sent to the subscriber terminal~
In the above sending operation, video and audio signals are sent through the video and audio output units 16 and 17 and the exchange 3 to the video/audio signal combining unit 18 in which a carrier of 4.5 MHz is frequency-modulated by the audio signal and then are superposed on the video signal (base band signal). The signal thus formed is sent to the subscriber terminal 7a through the subscriber's junction line 5. In the subscriber terminal 7a, the above signal is converted by a converter into a video signal of the NTSC system (or PAL sys-tem), and then is received by the television receiver.
In the case where the center 4 has completed the above sending operation, when the subscriber terminal 7a receives the busy tone because of the absence of idle trunk, or when the terminal 7a receives the talky message for reporting the stoppage of service, the key-board is turned off or the push-phone is put in the on-hook state, and the exchange 3 discon-nects the circuit after the detection of on-hook signal. Thus, the service terminates.
Next, explanation will be made of the case where an information service is required by the subscriber terminal 7b connected to the exchanges 3a and 3b of the sub-center 8, with reference to Fig. 5. The service procedure from the start to the judgment in the exchange 3b as to whether the service is stopped or not, is the same as has been explained in connec-~- ~ --10--': I

1~56349 tion with the subscriber terminal 7b. When the service is not stopped, the sub-center monitoring/controlling unit 27 sends out a signal for starting the center 4. Upon receipt of the above signal, the center 4 sends out a signal indicating that the center is ready to receive, and takes in the subscriber's number from the sub-center 8. Subsequently, a title (or index) is sent out, and then video and audio signals required by the subscriber terminal 7b are sent to the stationary picture re-ceiver 20 and an audio changeover/output unit 24 through two separate junction lines. The audio signal is superposed on the video signal in the same manner as the case where video and audio signals are sent from the center 4 to the subscriber terminal 7a.
The video and audio signals are time-divisionally transmitted from the center 4 to the sub-center 8 by a plur-ality of lines. These lines are spatially divided into two groups, one of which is used to transmit a stationary picture, a composite stationary picture, motion picture and a talking motion picture, and the other group is used to transmit audio signals with respect to the composite stationary picture, mo-tion picture and stationary picture.
As has been described hereinbefore, according to the present invention, since the subscriber's junction line for connecting a subscriber terminal to an exchange can be made short in length, the number of repeaters is reduced and there-fore the cost of the whole system can be reduced.

Claims (6)

1. A buffer memory dispersion type video/audio transmis-sion system with spatially and timewise divided inter-office junction lines comprising:
a center comprising a group of audio files for storing audio information, a group of video files for storing video information, and a central processing and controlling unit for executing a controlling operation in response to an infor-mation request received at said center from a subscriber ter-minal unit to fetch specific information from said audio and video file groups, and a multiplex transmitter for transmitting said information in a time-divisional fashion through one or a plurality of inter-office junction lines provided every kinds of said audio information and said video information, a plurality of subcenters coupled to said center, sub-scriber terminal units coupled to said subcenters through said plurality of inter-office junction lines for receiving the specific audio information and video information, each sub-center comprising video and audio buffer memories for tempor-arily storing the specific received audio and video informa-tion, and an exchange for selectively connecting a subscriber terminal unit requesting one information stored in said video and audio buffer memories by a much shorter length of cable than a length of said inter-office junction line, wherein said exchange comprises an exchange for video information and an exchange for telephone, and said plurality of subscriber terminal units are provided with the functions of receiving telephone information and audio/video information, each con-nected to the exchange through subscriber's junction lines.
2. A buffer memory dispersion type video/audio transmission system according to claim 1, wherein said center further comprises:
a connection matching unit coupled between the central processing unit and the video and audio files to provide access to the video and audio files for the central processing unit to select specific video and audio information from the files in response to a request from a subscriber;
a video output unit coupled to an [the] output of the video files by a video distributing coupling unit and a frame memory, said video output unit receiving through said video distributing coupling unit and said frame memory the specific video information selected from the video files by the central processing unit in response to the subscriber's request;
an audio output unit coupled to an [the] output of the audio files through an audio changeover circuit, said audio outout unit receiving through said audio changeover unit the specific information selected from said audio files by said central processing unit in response to said subscriber's request;
and means for coupling the outputs of said video output unit and said audio output unit to said subcenter over said time-division highway cable.
3. A buffer memory dispersion type video/audio transmission system according to claim 2, wherein said center further comprises a center exchange coupled to the output of said video output unit and said audio output unit, wherein said center exchange is connected directly to a subscriber which is coupled to the center without an intervening subcenter.
4 A buffer memory dispersion type video/audio transmission system according to claim 3, further comprising a video/audio signal combining unit coupled between said center exchange and said subscriber for combining said selected audio and video information and sending it to said subscriber terminal which is connected to said center without an intervening subcenter.
5. A buffer memory dispersion type video/audio transmission system according to claim 1, wherein a video signal which has been sent from said center to said subcenter through junction lines for connecting said center and said subcenter, is written in said buffer memory of said subcenter, wherein an audio signal which has been sent from said center to said subcenter through said junction lines, is combined by a video/audio signal comb-bining unit with a video signal which has been read out of said buffer memory, and wherein said video and audio signals thus combined are sent to a subscriber terminal through said exchange of said subcenter and a subscriber's junctions line.
6. A buffer memory dispersion type video-audio transmission system according to claim 1, wherein said exchange in said subcenter further includes means for coupling the information request from said subscriber terminal unit to said center.
CA000340229A 1978-11-24 1979-11-20 Buffer memory dispersion type video/audio transmission system with spatially and timewise divided inter-office junction lines Expired CA1156349A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP14415978A JPS5571343A (en) 1978-11-24 1978-11-24 Inter-office trunk line space division and time division-type buffer memory dispersive arrangement picture sound transmission system
JP144159/78 1978-11-24

Publications (1)

Publication Number Publication Date
CA1156349A true CA1156349A (en) 1983-11-01

Family

ID=15355563

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000340229A Expired CA1156349A (en) 1978-11-24 1979-11-20 Buffer memory dispersion type video/audio transmission system with spatially and timewise divided inter-office junction lines

Country Status (4)

Country Link
US (1) US4518989A (en)
JP (1) JPS5571343A (en)
CA (1) CA1156349A (en)
GB (1) GB2038594B (en)

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Publication number Publication date
GB2038594B (en) 1983-08-17
JPS5571343A (en) 1980-05-29
GB2038594A (en) 1980-07-23
US4518989A (en) 1985-05-21

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