EP1880542A1 - Procede ameliorant la stabilite d'image pour reception tv analogique mobile - Google Patents

Procede ameliorant la stabilite d'image pour reception tv analogique mobile

Info

Publication number
EP1880542A1
EP1880542A1 EP06753575A EP06753575A EP1880542A1 EP 1880542 A1 EP1880542 A1 EP 1880542A1 EP 06753575 A EP06753575 A EP 06753575A EP 06753575 A EP06753575 A EP 06753575A EP 1880542 A1 EP1880542 A1 EP 1880542A1
Authority
EP
European Patent Office
Prior art keywords
synchronization signals
synchronization
signal
reception
received
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Withdrawn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
EP06753575A
Other languages
German (de)
English (en)
Inventor
Wolfgang Sautter
Thomas Adam
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.)
Hirschmann Car Communication GmbH
Original Assignee
Hirschmann Car Communication GmbH
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 Hirschmann Car Communication GmbH filed Critical Hirschmann Car Communication GmbH
Publication of EP1880542A1 publication Critical patent/EP1880542A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/12—Devices in which the synchronising signals are only operative if a phase difference occurs between synchronising and synchronised scanning devices, e.g. flywheel synchronising
    • H04N5/126—Devices in which the synchronising signals are only operative if a phase difference occurs between synchronising and synchronised scanning devices, e.g. flywheel synchronising whereby the synchronisation signal indirectly commands a frequency generator
    • 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
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/60—Network structure or processes for video distribution between server and client or between remote clients; Control signalling between clients, server and network components; Transmission of management data between server and client, e.g. sending from server to client commands for recording incoming content stream; Communication details between server and client 
    • H04N21/61—Network physical structure; Signal processing
    • H04N21/6106—Network physical structure; Signal processing specially adapted to the downstream path of the transmission network
    • H04N21/6131—Network physical structure; Signal processing specially adapted to the downstream path of the transmission network involving transmission via a mobile phone network
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N17/00—Diagnosis, testing or measuring for television systems or their details

Definitions

  • the invention relates to a method for improving the image stability in mobile analog TV reception, which uses receiving means such as at least one antenna and a receiver, according to the features of the preamble of claim 1.
  • the known methods for the mobile reception of analog television signals are based on the direct use of the FBAS (color-picture-blanking-synchronous) signal supplied by a receiver, consisting essentially of tuner and demodulator.
  • Various diversity methods are used, such as switching diversity (DE 39 26 336 A1, DE 196 36 125 A1, DE 197 39 898 A1) or summation diversity (DE 199 29 284 A1).
  • switching diversity DE 39 26 336 A1, DE 196 36 125 A1, DE 197 39 898 A1
  • summation diversity DE 199 29 284 A1
  • the presence of an undisturbed synchronizing signal is necessarily required.
  • the directly received composite signal is at high input level or in case of multipath disturbances, which occurs both in mobile TV reception, often disturbed due to the movement of the vehicle or other influences severely.
  • Such a disturbed CVBS signal then leads to image disturbances such as horizontal and / or vertical traversal or offset of the image and thus to an insufficient quality of the television reception.
  • the object underlying the invention is therefore to be seen in the fact that the method with low technical complexity to improve the mobile terrestrial TV reception in poorly served areas and in areas with multipath propagation so that the stability of the image synchronization over the known receiving systems is significantly improved.
  • the deterministic synchronization signals contained in the television signal are generated synthetically locally in the receiver, wherein the synchronization signals received at good reception ratios are used to synchronize the locally synthesized synchronization signals in frequency and phase, whereas in bad reception conditions, the synthesized synchronization signals with high Frequency stability be continued regardless of the received synchronization signals and used for further signal processing.
  • the inventive method leads to a significant reduction of the image noise in the form of horizontal and / or vertical traversing or image offset, as they otherwise occur in mobile TV reception, especially in Schwachsignal- and multipath reception areas.
  • CVBS composite video burst sync
  • the essential components of the CVBS signal are the brightness (luminance) and color (chrominance) information of the image to be displayed as well as the associated blanking information, which is referred to below as a synchronization signal.
  • This synchronization signal includes both vertical and horizontal blanking information.
  • the waveform of these sync signals is fixed for a given TV standard, including the repetition rates and their allowable variation. Occur in the (terrestrial) transmission of the television signal disturbances of the synchronization signal, so that the blanking information can not be decoded correctly, this leads to display errors.
  • the TV picture may be shifted horizontally and / or vertically or the wrongly decoded blanking information may be visible as (noisy) black bars in the picture.
  • the shift or the position of the (noisy) black bars can change over time and a run through the image or the bar is the result.
  • the principle underlying the invention is the local generation of the deterministic synchronization signals. Since the waveform of this is known only the remaining free parameters, frequency and phase position, the received signal must be adjusted. This is done with good reception conditions, in which the synchronization signals can be decoded error-free.
  • a tracking synchronizing unit phase-locked loop, PLL is used for this purpose.
  • a tracking synchronization unit has the property of adjusting the frequency and phase of an oscillator to match the frequency and phase of a reference oscillator. In poor reception conditions, the local synchronization signals are now used instead of the received synchronization signals. It is essential that the continuation of the once synchronized locally generated synchronization signals with very high stability of the frequency determined at good reception conditions takes place.
  • the received composite video signal FBAS_1 is separated from the brightness and color signal (denoted by CVBS_2) in a synchronization-separation unit (also called sync-separation unit) of the synchronization component (denoted by CSYNC_1).
  • the variable in frequency and phase synchronization sync generator evaluates the synchronization component of the received composite signal, the CSYNC_1 signal and generates a local synchronization signal CSYNC_2, which, as described above in good reception conditions the input signal CSYNC_1 equalized, but continued in poor reception conditions independently.
  • the synthetic synchronization signal CSYNC_2 is again keyed into the received brightness and color signals FBAS_2 to again generate a complete CVBS output signal FBAS_3.
  • FIG. 2 An advantageous and low-wall application of the method of the main claim is shown in Figure 2.
  • the sync generator used therein has in addition to the already described properties (quality assessment of the input signal, generate and possibly adjust the phase and frequency) the ability to turn on or off the generated synthetic synchronization signal (denoted by CSYNC), depending on the determined quality of his Input signal FBAS_2.
  • the switchable synthetic synchronization signal is directly input into the received composite signal FBAS_1 and the output signal FBAS_2 thus generated is used for further signal processing.
  • This method allows the received composite signal to continue to be used directly in good reception conditions, but in the case of poor reception conditions, valid synchronization information is available in the signal FBAS_2.
  • the advantage of this method is that it allows for the implementation of a reduced circuit complexity compared to the method according to Figure 1.
  • FIG. 3 shows how the method according to the invention can be expanded by an antenna switch. This allows you to switch one of Several possible antennas to the receiving path, thus realizing a so-called switching diversity.
  • the advantage of this method is that the antenna switch can also be made on the basis of the already performed quality assessment of the received signal. This has the additional advantage of selecting the antenna that gives the best image stability.
  • both variants described can be expanded by an antenna switch in accordance with FIGS. 1 and 2.
  • FIG. 4 shows the inventive sync stabilization method with subsequent digital signal processing.
  • the stabilized composite video signal FBAS_3 is converted into a digital video signal (referred to as "digital video signal") in a video-analog-to-digital converter, which is then processed using digital signal processing methods and is then referred to as "digital video signal_2". to disposal.
  • FIG. 5 shows the low-effort implementation of the method according to the invention in digital signal processing.
  • the advantage here is that the digital signal processing unit also takes over the tasks of the sync generator which can be switched on and off.
  • the quality assessment is based on the digital video signal (digital video signal) and, on the other hand, the frequency and phase-variable synchronization signal is generated with the aid of this digital signal processing unit.
  • Figure 6 shows the extension of the method according to the invention to a plurality of parallel receiving paths, as they occur, for example, in a diversity receiver according to the published patent application DE 199 29 284 A1. All paths are routed to a common digital signal processing unit. This allows the comparison of the quality scores of the individual paths and a decision on the switching on and off of the individual synthetic synchronization signals (CSYNC_1 to CSYNC-N) not only based on their own quality rating but based on the quality assessment of all receive paths.
  • An advantageous embodiment of the method is to leave in poor reception conditions only the best of the N possible synchronization signals turned on. Thus, the quality evaluation for all other N - 1 possible receive paths based on the uninfluenced receive signals. This considerably facilitates the quality evaluation and thus reduces the risk of a misjudgment and the resulting incorrect decision by switching the synthetic synchronization signal on and off.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radio Transmission System (AREA)

Abstract

L'invention concerne un procédé améliorant la stabilité d'image pour une réception TV analogique, utilisant des moyens de réception tels qu'au moins une antenne et un récepteur, procédé caractérisé en ce que les signaux de synchronisation déterministiques contenus dans le signal de télévision sont générés synthétiquement localement dans un récepteur, en ce que les signaux de synchronisation reçus dans de bonnes conditions de réception sont utilisés pour synchroniser en fréquence et en position de phase les signaux de synchronisation générés localement synthétiquement, tandis que pour de mauvaises conditions de réception, les signaux de synchronisation générés synthétiquement sont transmis à stabilité de fréquence élevée, indépendamment des signaux de synchronisation reçus, et sont utilisés pour le traitement ultérieur de signaux.
EP06753575A 2005-05-11 2006-05-11 Procede ameliorant la stabilite d'image pour reception tv analogique mobile Withdrawn EP1880542A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102005021750 2005-05-11
PCT/EP2006/004456 WO2006120000A1 (fr) 2005-05-11 2006-05-11 Procede ameliorant la stabilite d'image pour reception tv analogique mobile

Publications (1)

Publication Number Publication Date
EP1880542A1 true EP1880542A1 (fr) 2008-01-23

Family

ID=37011939

Family Applications (1)

Application Number Title Priority Date Filing Date
EP06753575A Withdrawn EP1880542A1 (fr) 2005-05-11 2006-05-11 Procede ameliorant la stabilite d'image pour reception tv analogique mobile

Country Status (3)

Country Link
EP (1) EP1880542A1 (fr)
CN (1) CN101061706B (fr)
WO (1) WO2006120000A1 (fr)

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2835732A (en) * 1951-06-22 1958-05-20 Zenith Radio Corp Sync separator comprising electromechanical resonant line
US3527886A (en) * 1967-03-30 1970-09-08 Rca Corp Composite television video switching circuit
US4872055A (en) * 1987-02-04 1989-10-03 U. S. Philips Corporation Line synchronizing circuit in a picture display device
JP2728547B2 (ja) * 1990-06-13 1998-03-18 株式会社日立製作所 ダイバシティ受信装置
US5162910A (en) * 1990-10-03 1992-11-10 Thomson Consumer Electronics, Inc. Synchronizing circuit
JP3195926B2 (ja) * 1991-02-08 2001-08-06 フバ オートモティブ ゲゼルシャフト ミット ベシュレンクテル ハフツング ウント コンパニー コマンディッド ゲセルシャフト 自動車テレビジョン信号受信における受信妨害を除去するためのアンテナダイバーシチ受信装置
DE19636125B4 (de) * 1996-09-06 2007-12-06 Fuba Automotive Gmbh & Co. Kg Raumdiversity-Verfahren und -Schaltungsanordnung
DE19925868B4 (de) * 1999-06-07 2004-10-21 Microtune Gmbh & Co. Kg Diversity-TV-Empfangssystem
DE19929284A1 (de) * 1999-06-25 2001-01-04 Hirschmann Richard Gmbh Co Verfahren zum mobilen Empfang von Rundfunksignalen und Schaltungsanordnung zur Durchführung des Verfahrens

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2006120000A1 *

Also Published As

Publication number Publication date
WO2006120000A1 (fr) 2006-11-16
CN101061706A (zh) 2007-10-24
CN101061706B (zh) 2010-12-01

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