Telecommunications – Interference signal transmission
Patent
1996-01-19
1998-08-04
Powell, Mark R.
Telecommunications
Interference signal transmission
348 6, 348 10, 348460, 348461, 455 31, 455 62, H04N 100, H04N 700
Patent
active
057909377
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND
The present invention relates to simultaneous transmission of several different information via a television channel in the manner of multi-media-distribution and the recording and reproduction of multi-media-documents.
So called multi-media-documents are electronic documents which consists of:
text
still pictures
graphics
digital sound
digital video
any combination of the above mentioned kinds of data.
It is already known to use picture-in-picture television receivers and video text for providing different information. But the number of different information which may be transmitted by a normal television channel is restricted by bandwidth of television signal.
It is also known a multi-media terminal apparatus which can simultaneously operate a plurality of peripheral equipments connected to other multi-media terminal apparatuses on a network, see EP-A-0 435 344. The multi-media terminal apparatus is connected to other multi-media terminal apparatuses via a transmission line having a plurality of channels.
SUMMARY OF THE INVENTION
Transmission of digital television signals via direct broadcast satelite system (DBS), based on digital compression techniques, is also under development. Such a system can transmit digitally compressed video and audio signals and, optionally, associated control/conditional access data by means of satellite transmission. A large number of transmission channels with a net data rate between 20 to 30 Mbits/sec are provided. To compress video and audio the MPEG I algorithm (motion picture expert group) is used.
Therefore it is the task of this invention to build up a system which enables the distribution, recording and playback of a multiple of multi media documents with low costs.
The invention is based on the idea of using a television channel or parts of the bandwidth of it to distribute simultaneously a multiple of multi media documents, whereas for recording and playback purpose already known devices with additional functionality are used.
The method is that several multi media documents are read into a digital storage device like Compact Disc or in a digital video tape. These digital storage devices serve as a source of digital signals on the sending side. The digital signals are fed in several sub-channels into the multiplexer.
The number of possible subchannels and therefore the number of multi media documents simultaneously distributed is limited by:
the number of available transmission channels
the bandwidth of each channel
and the bitrate for each subchannel.
For instance the following distribution schemes on one channel are possible: (Assumption channel capacity 23.6 Mbit/sec) Example 1: 16 subchannels at the single Compact Disc (CD) data rate of around 1.4Mbit/s Example 2: 3 tv programs subchannels at 6.8 Mbit/s each plus 2 subchannels with each single CD data rate Example 3: 2 tv program subchannels at 8 Mbit/s each plus 2 subchannels with double CD data rate plus 1 subchannel with single CD data rate.
To transmit several subchannels containing different multi media documents the subchannels are time-multiplexed in the transmission channel.
This has the following advantages:
flexible usage of the overall channel capacity is possible
otherwise unused remaining bandwitdh within a channel can be used to transmit multi media documents
In accordance with the present invention, there are provided on broadcasting studio side several sub-channels with average bit rates ranging from several kilobits/s up to the whole channel capacity, which are fed into a multiplexer. In the multiplexer the sub-channels are time-multiplexed and a control information is added. Afterwards the data is preferred undergone a channel coding to assure error-free transmission. The final step at the sending side is the modulation into an analogous signal and the emission via the different media, e.g. satellite, cable network or terrestrial distribution.
On the receiving side the signal passes the demodulation, error check and concealment and the demultiplexer after reception via satelite,
REFERENCES:
patent: 4787085 (1988-11-01), Suto et al.
patent: 5173900 (1992-12-01), Miller et al.
Miller John W.
Powell Mark R.
Thomson Multimedia S.A.
Tripoli Joseph S.
Wein Frederick A.
LandOfFree
Method and apparatus for the distribution of multi-media documen does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for the distribution of multi-media documen, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for the distribution of multi-media documen will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1190897