Japanese Patent Application No. Hei 5-65183 (Japanese Patent Laid-Open No. Hei 6-276169)
Digital Information Transmission System,
Digital Transmission Device,
and Digital Reception Device

This invention is related to the ISDB (Integrated Services Digital Broadcasting) transmission system which transmits various integrated digital information. The idea is to drastically reduce the cost of reception sets that receive small amounts of data and lower data speed services.
To accomplish this, a variety of digital information is transmitted in a packet format. The broadcaster multiplexes packet data belonging to the same service on an optionally designated transmission slot. The designated position of the transmission slot allows the receiver to utilize specific subject slots and necessary packets in the slot for processing. This allows enough time for necessary data management such as error correction and header recognition of the data.
The example illustrated in the inserted figure shows the compositions of the transmission and reception sides, respectively. On the transmission side, audio and visual data is transformed into a packet with an addition of an error correction test bit. The data packet is then assigned a slot and multiplexed with additional information, based on service slot information provided by an outside source. Simultaneously, this slot information is also inserted into a packet to be multiplexed with other information such as visual data. A transmission signal is generated through a modulation circuit following the addition of a frame synchronous signal. The reception side reproduces received data by means of a recovery circuit and passes the synchronous signal onto a frame decoder circuit that defines and reproduces the data in each transmission slot. The slot decoder circuit selects only the slots which include subject data packets identified by the attached slot information. While the slot information in this example was supplied from an outside source, this information can be established beforehand so that the reception side determines the order of transmission slots.
This invention sufficiently lowers the data processing speed by multiplexed digital subject matter in an optionally allotted slot in addition to limiting the number of slots being decoded at the time of reception. This enables the simplification of reception devices.

(Inventors: Kouji OSAKI, Seiichi NANBA, Akira OHYA, Naoki KAWAI, Takeshi KIMURA, Hiroyuki HAMADA)






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