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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