EP0934639A1 - Dispositif et procede pour la reception de donnees transmises par une technique de transmission de donnees asynchrone - Google Patents

Dispositif et procede pour la reception de donnees transmises par une technique de transmission de donnees asynchrone

Info

Publication number
EP0934639A1
EP0934639A1 EP98930730A EP98930730A EP0934639A1 EP 0934639 A1 EP0934639 A1 EP 0934639A1 EP 98930730 A EP98930730 A EP 98930730A EP 98930730 A EP98930730 A EP 98930730A EP 0934639 A1 EP0934639 A1 EP 0934639A1
Authority
EP
European Patent Office
Prior art keywords
clock
data
studio
data signals
transmission
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.)
Withdrawn
Application number
EP98930730A
Other languages
German (de)
English (en)
Inventor
Ulf Assmus
Michael Roth
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.)
Deutsche Telekom AG
Original Assignee
Deutsche Telekom AG
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 Deutsche Telekom AG filed Critical Deutsche Telekom AG
Publication of EP0934639A1 publication Critical patent/EP0934639A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H60/00—Arrangements for broadcast applications with a direct linking to broadcast information or broadcast space-time; Broadcast-related systems
    • H04H60/02—Arrangements for generating broadcast information; Arrangements for generating broadcast-related information with a direct linking to broadcast information or to broadcast space-time; Arrangements for simultaneous generation of broadcast information and broadcast-related information
    • H04H60/04—Studio equipment; Interconnection of studios
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04H—BROADCAST COMMUNICATION
    • H04H60/00—Arrangements for broadcast applications with a direct linking to broadcast information or broadcast space-time; Broadcast-related systems
    • H04H60/76—Arrangements characterised by transmission systems other than for broadcast, e.g. the Internet
    • H04H60/81—Arrangements characterised by transmission systems other than for broadcast, e.g. the Internet characterised by the transmission system itself
    • H04H60/93—Wired transmission systems
    • H04H60/95—Wired transmission systems for local area
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
    • H04N21/242—Synchronization processes, e.g. processing of PCR [Program Clock References]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
    • H04N21/4302—Content synchronisation processes, e.g. decoder synchronisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/06—Generation of synchronising signals
    • H04N5/067—Arrangements or circuits at the transmitter end
    • H04N5/073—Arrangements or circuits at the transmitter end for mutually locking plural sources of synchronising signals, e.g. studios or relay stations

Definitions

  • the invention relates to a device for receiving data transmitted by means of an asynchronous data transmission technology, in particular audio and video data, to which a clock signal is fed, with a memory device.
  • the invention further relates to a method for transmitting and receiving data signals, in particular audio and video data signals, between two studios, each studio having a studio clock.
  • a studio is a facility that has means for processing audio and image data signals. Data processing in the studios is taking place increasingly digitally, which requires a joint studio cycle to supply the processing equipment.
  • the studio clocks In the case of data transmission between two studios, for example, there is a need for the studio clocks to be synchronized so that disruptions which occur during the reception and further processing of data as a result of data loss are avoided.
  • a synchronization of the studio clocks is achieved, for example, in that in a so-called master / slave synchronization, a studio provides a clock as the master, which after its transmission is used by the other studio to synchronize its own studio clock.
  • a common clock is made available to the studios connected to the network by a common network operator.
  • the useful signal is usually used for the synchronization or transmission of the synchronization signal.
  • ATM Asynchronous Transfer Mode
  • a clock recovery on the catch side based on the amount of data received per unit of time.
  • This usually results in a higher-frequency jitter with a very low and therefore not disturbing amplitude and a wander based on the principle of ATM technology with a relatively large amplitude and very low frequency.
  • Due to the low frequency of the wander below the mHz range the technology used to eliminate jitter in the form of a PLL (phase locked loop) circuit with extreme low-pass behavior is not suitable, since it is one of the changing loads of individual ATM switching nodes ATM data transmission network depends.
  • this wander causes a significant deterioration in the signal, which leads, for example, to audio noises at more or less regularly large intervals in the case of audio signals.
  • the object of the present invention is therefore to create a device with which error-free reception of data, in particular video and / or audio data, between two with one another . synchronized studios is possible.
  • ATM Video Data
  • PDH Plesiochronous Digital Hierarchy
  • SDH Synchronous Digital Hierarchy, in USA SONET
  • FIFO First In First Out
  • the size of the FIFO memory being designed such that data can be stored over a period of preferably n * 150 ⁇ s.
  • the period results from the number of possible Switching centers within a transmission link, with 100 ⁇ s per switching node to be set for an unloaded network and approximately 250 ⁇ s for a loaded network.
  • a studio is preferably selected as the master, which transmits a clock signal to the other studio.
  • a means is preferably provided which is designed to adapt the received data stream to the studio clock.
  • the means recognizes times at which a falsification of the digital signal after the conversion of the digital signal into the analog signal has no perceptible impairment.
  • this point in time is recognized, for example, when the state of rest (no signal) is recognized in the signal over several samples.
  • the image boundaries are advantageously recognized and then entire images are omitted or read twice.
  • a switchover device which classifies the data received via the network and forwards it to the corresponding receiver.
  • the audio and video data signals represent a class that the studio needs for further processing be fed.
  • Another class is represented, for example, by telephone data signals which are supplied by the switching device to a connected telephone system.
  • computer data belong to a class that is transmitted via a so-called LAN (Local Area Network) network and is supplied to the corresponding network by the switching device.
  • the switching device preferably also works to bundle the different data signals.
  • the object of the present invention is also achieved by a method which has the features of claim 11.
  • Figure 1 is a block diagram of the structure of two studios and their connection
  • FIG. 2 is a block diagram of the connection of two studios with a normal clock supply
  • FIG. 3 shows a block diagram of several studios connected via a common network.
  • a device 1 is shown in a schematic representation, which is connected to a substantially similarly constructed further device 3 via a connection 5.
  • Both devices are devices for processing digital data, namely digital audio and video data, which are used in radio and television technology.
  • Such devices 1, 3 are part of digitally working radio and / or television studios.
  • the two facilities 1, 3 are referred to below as studios.
  • Such a studio has, for example, the task of processing the data of a live broadcast sent by another studio in real time and transmitting it to the viewers via terestrial or wired transmission channels.
  • the studio 1 comprises a transmission device 7, which is connected to the transmission link 5 at the receiving end.
  • the transmission device 7 carries out a bundling of different data streams, for example audio and video data streams, for example using the multiplex method, in order to transmit these via a common line of the transmission link 5.
  • the data transmission link is, for example, an STM1 connection with a data transmission rate of 155.52 Mbit / s.
  • Another task of the transmission device 7 is to be seen in the data signals to be transmitted in a form necessary for the transfer.
  • the ATM method Asynchronous Transfer Mode
  • this method is known per se, its description is omitted.
  • the transmission device 7 separates the received data stream into an audio data stream and a video data stream, the data packets being unpacked at the same time.
  • terminal adapters Two devices 9, 11, hereinafter referred to as terminal adapters, are connected to the transmission device 7 via data lines 13.
  • the terminal adapter 9 is assigned to the video data stream, while the terminal adapter 11 is assigned to the audio data stream.
  • the terminal adapters are used to adapt the data coming from the transmission device 7 to the form required within the studio 1, which normally also includes the recovery of the clock used on the transmitter side.
  • the terminal adapters 9 and 11 have to divide the data stream into individual data packets, so-called ATM cells, for transmission in ATM technology, each data packet also containing control information in addition to the actual user data.
  • An ATM cell is usually 53 bytes long.
  • Such a terminal adapter comprises - as shown schematically in section A of FIG. 1 - a control unit 15 and a storage unit 17.
  • This storage unit comprises at least one as FIFO (First In First Out) memory area 19, to which the data coming from the transmission device 7 are fed.
  • the control unit 15 ensures that the data are read out of the FIFO memory 19 in one cycle, which is provided by a clock source 21 provided within the studio 1. This measure is referred to below as the studio measure.
  • the function of the FIFO memory 19 is therefore to temporarily store a number of data.
  • the size of the FIFO memory depends on the one hand on the data transmission rate and on the other hand on the number of switching centers present in the transmission path.
  • the storage capacity could be 300 ATM cells at a transmission rate of 34 Mbit / s and 100 ATM cells at a transmission rate of 8 Mbit / s. This results in a memory size of 13 ATM cells per 1 Mbit / s data transfer rate.
  • the FIFO memory 19 should also be large enough to compensate for time delays caused by transmission technology. Thus, delays referred to as cell delay variation (CDV) occur through switching centers in the transmission link, which cause a delay of 100 ⁇ s for an unloaded network node and up to 250 ⁇ s for a network node that is loaded (switching center).
  • CDV cell delay variation
  • the data temporarily stored in the FIFO memory 19 are then read out in the studio cycle and fed to a downstream audio or video coding / decoding device 23 or 25.
  • the audio data are, for example, transmission rate of 2.048 Mbit / s to the audio coding / decoding device 23.
  • the two coding / decoding devices 23, 25 also receive the studio clock from the clock source 21 for further processing of the data. Since the further processing of the corresponding data is not relevant to the present invention, a corresponding description is dispensed with.
  • the studio adapters are fed to the terminal adapters 9, 11 in order to read out the received data from the FIFO memory 19 in the studio admission.
  • clock recovery in the terminal adapter from the received data stream is thus dispensed with.
  • the transmitter is Studio 3, which corresponds to Studio 1 in terms of its structure. A repeated description of the parts identified by the same reference numerals is therefore omitted.
  • the studio clock 21 of the studio 1 is transmitted to the studio 3 via the transmission path 5 for synchronization.
  • this clock signal is transmitted by the supply device 7 the clock generator 21 ! fed and used there to synchronize the generated studio clock.
  • This type of synchronization is also called master / slave synchronization, with Studio 1 working as a master and Studio 3 as a slave.
  • the advantage of this type of data transmission is that the advantages of ATM technology, such as great flexibility in data rates, use of a public ATM network, use of dial-up connections, no closed user class in a special network, no special network technologies etc. are retained without to have to accept the inherent disadvantage of wandering (loss of synchronization) in this ATM technology.
  • wandering loss of synchronization
  • FIG. 2 Another type of synchronization of two studios 1, 3 is shown in FIG. 2.
  • the two studios 1, 3 themselves correspond to the studios described above, so that there is no further description. The only difference is that both studios do not necessarily have the clock sources 21 to be synchronized. Rather, a clock signal referred to as a normal clock is supplied to them by a central clock generator, for example the network operator 27 (which then synchronizes clock sources 21 that may be used).
  • a further exemplary embodiment is shown in FIG. 3, three studios 1, 3, 29 now being able to be connected to one another via a common ATM network 31. All three studios 1, 3, 29 have an identical structure and correspond to the studio already described with reference to FIG. 1. A description of the parts identified by the same reference symbols is therefore omitted.
  • the clock necessary for synchronization is generated by a central clock generator 27 and made available to each studio 1, 3, 29. There it is used to synchronize the studio clocks.
  • the ATM network 31 can be, for example, the public ATM network (fixed or dial-up connections). Due to the possibly larger CDV delay in data transmission, the FIFO memory of the terminal adapter must be adapted accordingly.
  • the transmission devices 7 with a switchover unit, which enables the bundling or separation of data of different classes (audio / video data, telephone data, computer data).
  • the ATM network 31 can thus be used for different services.
  • control unit 15 which is designed to adapt the received data stream to the studio clock.
  • the means recognizes times at which a falsification of the digital gnals after the conversion of the digital into the analog signal has no perceptible impairment.
  • this point in time is recognized, for example, when the state of rest (no signal) is recognized in the signal over several samples.
  • the image boundaries are advantageously recognized and entire images are then omitted or read twice. It can also be used to transfer data between a synchronized and an unsynchronized studio.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Multimedia (AREA)
  • Data Exchanges In Wide-Area Networks (AREA)
  • Synchronisation In Digital Transmission Systems (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)

Abstract

L'invention concerne un dispositif pour la réception de données, en particulier de données audio et vidéo, transmises par une technique de transmission de données asynchrone, dispositif auquel est amené un signal d'horloge. Ce dispositif comprend un dispositif de mémoire (17) qui sauvegarde les données reçues de manière intermédiaire pendant la durée nécessaire à la compensation de retards de transmission (variation de retard de cellule). L'invention est caractérisée en ce que le signal d'horloge est amené au dispositif de mémoire (17) pour la lecture des données. L'invention concerne en outre un procédé de transmission et de réception de signaux de données par une technique de transmission de données asynchrone, les signaux reçus faisant l'objet d'une sauvegarde intermédiaire et étant lus à la fréquence d'horloge de studio.
EP98930730A 1997-06-06 1998-05-26 Dispositif et procede pour la reception de donnees transmises par une technique de transmission de donnees asynchrone Withdrawn EP0934639A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19723760A DE19723760B4 (de) 1997-06-06 1997-06-06 Einrichtung und Verfahren zum Empfang von Daten
DE19723760 1997-06-06
PCT/EP1998/003086 WO1998056126A1 (fr) 1997-06-06 1998-05-26 Dispositif et procede pour la reception de donnees transmises par une technique de transmission de donnees asynchrone

Publications (1)

Publication Number Publication Date
EP0934639A1 true EP0934639A1 (fr) 1999-08-11

Family

ID=7831593

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98930730A Withdrawn EP0934639A1 (fr) 1997-06-06 1998-05-26 Dispositif et procede pour la reception de donnees transmises par une technique de transmission de donnees asynchrone

Country Status (4)

Country Link
US (1) US8436938B1 (fr)
EP (1) EP0934639A1 (fr)
DE (1) DE19723760B4 (fr)
WO (1) WO1998056126A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0012774D0 (en) * 2000-05-25 2000-07-19 Radioscape Ltd Digital streaming media multiplex architecture
DE102009003851A1 (de) 2009-04-30 2010-11-11 Lear Corporation Gmbh Verfahren und Vorrichtung zur Wiedergabe von digitalen Audiosignalen
DE102010061076B8 (de) 2010-09-30 2012-07-19 Lear Corporation Gmbh Verfahren und Vorrichtung zur Versendung von digitalen Audiosignalen

Family Cites Families (10)

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Publication number Priority date Publication date Assignee Title
JPH02165752A (ja) 1988-12-19 1990-06-26 Matsushita Electric Ind Co Ltd ディジタル機器
JP2600496B2 (ja) * 1990-12-20 1997-04-16 日本電気株式会社 セル位相乗換回路
US5396492A (en) * 1993-04-28 1995-03-07 At&T Corp. Method and apparatus for adaptive clock recovery
US5652627A (en) * 1994-09-27 1997-07-29 Lucent Technologies Inc. System and method for reducing jitter in a packet-based transmission network
EP0718995A1 (fr) * 1994-12-20 1996-06-26 International Business Machines Corporation Appareil et méthode pour synchroniser des signaux d'horloge pour des liaisons numériques
JP4297518B2 (ja) * 1995-03-06 2009-07-15 沖電気工業株式会社 音声・ビデオ復号装置
DE19539474A1 (de) * 1995-10-24 1997-04-30 Daimler Benz Aerospace Ag Verfahren zur Rückgewinnung eines synchronen Datentakts und Anordnung zum Durchführen des Verfahrens
US5703877A (en) * 1995-11-22 1997-12-30 General Instrument Corporation Of Delaware Acquisition and error recovery of audio data carried in a packetized data stream
US5822383A (en) * 1995-12-15 1998-10-13 Cisco Technology, Inc. System and method for maintaining network synchronization utilizing digital phase comparison techniques with synchronous residual time stamps
US5870087A (en) * 1996-11-13 1999-02-09 Lsi Logic Corporation MPEG decoder system and method having a unified memory for transport decode and system controller functions

Non-Patent Citations (1)

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Title
See references of WO9856126A1 *

Also Published As

Publication number Publication date
DE19723760A1 (de) 1998-12-10
US8436938B1 (en) 2013-05-07
DE19723760B4 (de) 2006-07-13
WO1998056126A1 (fr) 1998-12-10

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