 |
Claims  |
|
|
What is claimed is:
1. A method of combining a plurality of digital programs into a multiplex
data stream for transmitting said programs from an origination point to at
least one remote location, wherein each program comprises a single bit
stream containing a combination of related digital services, said method
comprising the steps of:
a) multiplexing selected ones of the digital programs to generate a
subframe data stream having a format comprising a continuous sequence of
subframes different portions of each subframe being allocated to different
ones of said digital programs;
b) generating for each subframe a subframe multiplex map that at least
indirectly specifies which portions of that subframe are allocated to
which of said selected digital programs, and inserting the subframe
multiplex map in the subframe;
c) repeating step (a) and (b) a selected number of times, each time for
different selected ones of said digital programs, thereby generating a
plurality of subframe data streams each containing different ones of said
digital programs and each comprising a continuous sequence of subframes;
d) multiplexing selected ones of the subframe data streams to generate said
multiplex data stream, said multiplex data stream having a format
comprising a continuous sequence of superframes, each superframe
containing at least one subframe from at least one of said selected
subframe data streams; and
e) generating, for each superframe in the multiplex data stream, a
superframe map that specifies the location of each subframe within that
superframe, and inserting the superframe map in that superframe.
2. A method according to claim 1 wherein each subframe has a format
comprising a plurality of lines, a first group of lines in each subframe
defining a subframe transport layer region and a second group of lines
defining a program data region, and wherein step (a) comprises performing
the following steps for each subframe:
(i) partitioning the program data region of the subframe into a plurality
of program data packets;
(ii) allocating different portions of each program data packet in the
subframe to different ones of said programs;
(iii) generating a program multiplex control packet that specifies which
portions of each program data packet in the subframe are allocated to
which programs; and
(iv) inserting the program multiplex control packet in the transport layer
region of the subframe, the subframe multiplex map generated in step (b)
for that subframe specifying the location of the program multiplex control
packet within the transport layer region.
3. A method according to claim 2 wherein each of said programs has a
respective data rate, and wherein step (a)(ii) comprises allocating
different portions of each program data packet to different ones of said
programs in proportion to the respective data rates of said programs.
4. A method according to claim 3 further comprising the step of adjusting,
on a per subframe basis, the size of the portions allocated to each
program as the respective data rates of the programs change.
5. A method according to claim 2 further comprising the step of:
(a') generating a plurality of system related data packets including system
data packets (SDP's), system teletext packets (STT's), addressable data
packets (ADP's), service seed packets (SSP's) and program virtual channel
map packets (PVCMP's); and
(b') inserting selected ones of said system related data packets in the
transport layer region of each subframe, the subframe multiplex map
generated in step (b) for each subframe specifying the location of each
system related data packet inserted within the transport layer region of
that subframe.
6. A method according to claim 1 wherein each superframe has a format
comprising an adjustable number of successive blocks, a first portion of
each block comprising a block synchronization byte (BSYNC), a second
portion of each block comprising a data portion, and a last portion of
each block comprising a block error code generated in accordance with a
block error coding scheme.
7. A method according to claim 6 wherein a first group of blocks in each
superframe define a superframe transport layer region of that superframe,
and a second group of blocks define a subframe data region, the superframe
map generated for each superframe being inserted in the superframe
transport layer region of that superframe.
8. A method according to claim 7 wherein each subframe has a format
comprising a plurality of lines, and wherein the data portion of each
block in the subframe data region of each superframe contains a single
line of one of the subframes in that superframe.
9. A method according to claim 6 further comprising the step of inserting,
in a first block of each superframe, a superframe synchronization word
(FSYNC), and wherein the superframe map for each superframe is inserted in
the superframe immediately following the superframe synchronization word.
10. A method according to claim 1 wherein each superframe has a format
comprising an adjustable number of successive blocks, a first group of
blocks in each superframe defining a superframe transport layer region of
that superframe, and a second group of blocks defining a subframe data
region, said method further comprising the steps of:
(i) generating a subframe virtual channel map packet that contains
information that specifies, for each program, which subframe data stream
contains that program; and
(ii) periodically inserting the subframe virtual channel map packet in the
transport layer region of one of the successive superframes, the
superframe map for each superframe into which the subframe virtual channel
map is inserted further specifying the location of the subframe virtual
channel map packet within the transport layer region of that superframe.
11. A method according to claim 1 further comprising the step of
transmitting successive superframes of said multiplex data stream at a
constant rate.
12. A method according to claim 6 wherein each block comprises a
predetermined number of bits, and wherein said method further comprises
the step of transmitting successive superframes of said multiplex data
stream at a constant rate such that the multiplex data stream is
transmitted at a bit rage equal to F.sub.SF (n)(B) bits per second, where
F.sub.SF is the rate at which successive superframes are transmitted, n is
the number of blocks in each superframe, and b is the number of bits in
each block.
13. A method of decoding a multiplex data stream of the type recited in
claim 1, said method comprising the steps of:
a) receiving the multiplex data stream and selecting one of said programs;
b) determining which subframe data stream contains the selected program;
c) for each successive superframe of the received multiplex data stream,
performing the following steps:
(i) extracting the superframe map from the superframe and determining from
the extracted superframe map the location of each subframe within that
superframe; and
(ii) extracting from the superframe the subframe in that superframe that is
one of the subframes of the subframe data stream that contains the
selected program;
d) for each subframe extracted in step (c)(ii), performing the following
steps:
(i) extracting the subframe multiplex map from the subframe and
identifying, based at least in-part upon information contained within that
multiplex map, which portion of the subframe is allocated to the selected
program; and
(ii) extracting the identified portion from the subframe; and
e) combining the portions extracted from each subframe in step (d)(ii) to
reconstruct the selected program.
14. A method according to claim 13 wherein the multiplex data stream
contains mapping information that specifies, for each program, which
subframe data stream contains that program, and wherein step (b)
comprises:
(i) extracting the mapping information from the received multiplex data
stream; and
(ii) determining from the extracted mapping information which of the
subframe data streams contains the selected program.
15. A method according to claim 13 wherein each subframe of each subframe
data stream has a format comprising a plurality of successive lines, a
first group of lines in each subframe defining a transport layer region of
that subframe and a second group of lines defining a program data region,
and wherein the program data region of each subframe is partitioned into a
plurality of program data packets and different portions of each program
data packet are allocated to different ones of said programs, and further
wherein the transport layer region of each subframe contains a program
multiplex control packet that specifies which portions of each program
data packet in that subframe are allocated to which programs and the
subframe multiplex map in each subframe specifies the location, within the
transport layer region, of the program multiplex control packet for that
subframe, and still further wherein step (d) comprises performing the
following steps for each subframe:
(i) extracting the subframe multiplex map from the subframe and determining
therefrom the location of the program multiplex control packet within the
transport layer region of the subframe;
(ii) extracting the located program multiplex control packet from the
transport layer region;
(iii) identifying, based upon the extracted program multiplex control
packet, which portion of each program data packet of the subframe is
allocated to the selected program; and
(iv) extracting the portion identified in step (d)(iii) from each of the
program data packets in the subframe.
16. An encoder apparatus for combining a plurality of digital programs into
a multiplex data stream, wherein each program comprises a single bit
stream containing a combination of related digital services, said encoder
comprising:
a control computer for controlling the operation of the encoder;
a plurality of subframe multiplexers, each coupled to the control computer
and each being coupled to receive a respective group of said programs,
each subframe multiplexer being operative to multiplex its respective
group of programs to form a subframe data stream having a format
comprising a continuous sequence of subframes wherein different portions
of each subframe are allocated to different ones of said respective group
of programs, each subframe multiplexer being further operative to insert,
in each subframe, a subframe multiplex map that specifies, at least
indirectly, which portions of each subframe are allocated to which
programs; and
a superframe multiplexer coupled to each of said subframe multiplexers for
receiving said subframe data streams and for multiplexing selected ones of
said subframe data streams to generate said multiplex data stream, said
multiplex data stream having a format comprising a continuous sequence of
superframes, each superframe containing at least one subframe from at
least one of said selected subframe data streams, said superframe
multiplexer being further operative to generate, for each superframe in
the multiplex data stream, a superframe map that specifies the location of
each subframe contained in that superframe, and to insert the superframe
map in that superframe.
17. An encoder according to claim 16 wherein each subframe has a format
comprising a plurality of lines, a first group of lines in each subframe
defining a subframe transport layer region and a second group of lines
defining a program data region, and wherein each subframe multiplexer
comprises:
a subframe controller coupled to the control computer for generating, for
each subframe, the subframe multiplex map and at least one program
multiplex control packet;
a program multiplexer coupled to the subframe controller and responsive to
said program multiplex control packets for multiplexing said respective
group of programs in a time-division manner to produce a continuous
sequence of program data packets, different portions of each program data
packet being allocated to different ones of said group of programs; and
a subframe builder coupled to the subframe controller and to said program
multiplexer for constructing each subframe in accordance with the subframe
multiplex map generated for that subframe, wherein for each subframe, the
subframe builder is operative; (i) to insert a number of consecutive
program data packets in the program data region of the subframe, (ii) to
insert the program multiplex control packet for that subframe in the
transport layer region of the subframe at a location specified by the
subframe multiplex map for that subframe, and (iii) to insert the subframe
multiplex map at a beginning of the subframe.
18. An encoder according to claim 17 wherein, for each program data packet
to be inserted in a particular subframe, the program multiplex control
packet generated for that subframe by the subframe controller specifies
which portions of each program data packet are to be allocated to which
programs, and wherein the program multiplexer is responsive to the
multiplex control packet for generating each of the program data packets
in accordance with the information specified therein.
19. An encoder according to claim 17 wherein the subframe builder is
further operative to insert a subframe synchronization word (SFSYNC) in a
first line of each subframe and to insert the subframe multiplex map in
each frame such that the subframe multiplex map immediately follows the
subframe synchronization word (SFSYNC).
20. An encoder according to claim 17 wherein the control computer is
further operative to construct a plurality of system related data packets
including system data packets (SDP's), system teletext packets (STT's),
addressable data packets (ADP's), service seed packets (SSP's) and program
virtual channel map packets (PVCMP's), said subframe builder in each
subframe multiplexer inserting selected ones of said system related data
packets in the transport layer regions of each subframe, the subframe
multiplex map generated for each subframe by the subframe controller
specifying the number and location of each system related data packet to
be inserted in the transport layer region of that subframe.
21. An encoder according to claim 18 wherein each of said digital programs
has a respective data rate and wherein said portions of each program data
packet are allocated to said programs in proportion to the respective data
rates of each program.
22. An encoder according to claim 21 wherein said subframe multiplexer is
further operative to adjust, on a per subframe basis, the size of each
portion of each program data packet allocated to a particular program as
the respective data rates of each program change.
23. An encoder according to claim 16 wherein said superframe multiplexer
comprises:
a superframe controller coupled to the control computer for generating said
superframe map; and
a superframe builder coupled to the superframe controller and coupled to
receive successive subframes from each subframe multiplexer for
constructing each superframe in accordance with the superframe map
generated by the superframe controller, and for inserting each superframe
map in its respective superframe.
24. An encoder according to claim 23 wherein said superframe multiplexer
further comprises an interleaver coupled to an output of said superframe
builder for interleaving portions of each superframe to reduce burst
errors during subsequent transmission of the multiplex data stream to a
remote location.
25. An encoder according to claim 23 wherein each superframe has a format
comprising an adjustable number of successive blocks, a first group of
blocks in each superframe defining a superframe transport layer region of
that superframe and a second group of blocks defining a subframe data
region, said superframe builder including:
means for inserting a block syncrhonization byte (BSYNC) in a first portion
of each block; and
means for inserting a superframe syncrhonization word (FSYNC) in a first
block of each superframe.
26. An encoder according to claim 25 wherein the superframe multiplexer
further comprises block error coding means for generating a block error
code for each block and appending the block error code to the block.
27. An encoder according to claim 23 wherein the control computer is
further operative to generate a subframe virtual channel map packet that
contains information that specifies, for each program, which subframe data
stream contains that program, and wherein the superframe builder of the
superframe multiplexer further comprises means for periodically inserting
the subframe virtual channel map packet in the transport layer regions of
selected superframes, the superframe map for each superframe into which
the subframe virtual channel map packet is inserted further specifying the
location of the subframe virtual channel map packet within that
superframe.
28. A decoder for use at a remote location to decode a multiplex data
stream received at that location, said received multiplex data stream
containing a multiplexed combination of digital programs and having a
format comprising a continuous sequence of superframes each comprising a
predetermined number of blocks, a first group of blocks in each superframe
defining a transport layer region of that superframe and a second group of
blocks defining a subframe data region, the subframe data region of each
superframe comprising a multiplexed combination of subframes, different
portions of each subframe being allocated to different ones of said
digital programs and at least one subframe in each superframe containing
data for a different group of said programs than another subframe in that
superframe, said decoder comprising:
a receiver for receiving successive superframes of the multiplex data
stream;
a selector for selecting at least one of said digital programs for
extraction from said received multiplexed data stream;
a superframe demultiplexer comprising:
a superframe map extractor for locating and extracting a superframe map
from a received superframe of the received multiplex data stream, said
superframe map specifying the location of each subframe contained within
that superframe; and
a subframe extractor at least indirectly responsive to the extracted
superframe map for identifying which subframe in the received superframe
contains data for the selected program and for extracting that subframe
from the received superframe; and
a subframe demultiplexer coupled to the superframe demultiplexer for
receiving the extracted subframe from the superframe demultiplexer, said
subframe demultiplexer comprising:
a subframe multiplex map extractor for extracting a subframe multiplex map
from the extracted subframe that specifies, at least indirectly, which
portions of the subframe are allocated to which digital programs; and
a program extractor responsive to the extracted subframe multiplex map for
identifying, based at least in-part upon information contained in the
subframe multiplex map, which portion of the subframe is allocated to the
selected program, and for extracting the identified portion from the
subframe.
29. A decoder according to claim 28 wherein the multiplex data stream
contains mapping information that specifies, for each program, which
subframe data stream contains that program, and wherein the superframe
demultiplexer further comprises means for extracting the mapping
information from the received multiplex data stream and identifying
therefrom which subframe in the received superframe contains data for the
selected program.
30. A decoder for use at a remote location to decode a multiplex data
stream received at that location, said received multiplex data stream
containing a multiplexed combination of digital programs and having a
format comprising a continuous sequence of superframes each containing a
multiplexed combination of subframes, each subframe comprising a transport
layer region and a program data region, the program data region of each
subframe being partitioned into a plurality of program data packets,
different portions of each program data packet being allocated to
different ones of said digital programs, at least one subframe in each
superframe containing data for a different group of said programs than
another subframe in that superframe, the transport layer region of each
subframe containing a program multiplex control packet that specifies, for
each program data packet within that subframe, which portions of each
program data packet are allocated to which programs, the transport layer
region of each subframe further containing a subframe multiplex map which
specifies, for that subframe, the location of the program multiplex
control packet contained in the transport layer region of that subframe,
said decoder comprising:
a receiver for receiving successive superframes of the multiplex data
stream;
a selector for selecting at least one of said digital programs for
extraction from said received multiplexed data stream;
a superframe demultiplexer comprising:
a superframe map extractor for locating and extracting a superframe map
from a received superframe of the received multiplex data stream, said
superframe map specifying the location of each subframe contained within
that superframe; and
a subframe extractor at least indirectly responsive to the extracted
superframe map for identifying which subframe in the received superframe
contains data for the selected program and for extracting that subframe
from the received superframe; and
a subframe demultiplexer coupled to the superframe demultiplexer for
receiving the extracted subframe from the superframe demultiplexer, said
subframe demultiplexer comprising:
a subframe multiplex map extractor for extracting the subframe multiplex
map from the received subframe and for identifying therefrom the location
of the program multiplex control packet within the transport layer region
of that subframe;
means for extracting the program multiplex control packet from the
transport layer region of the received subframe; and
a program extractor responsive to the extracted program multiplex control
packet for identifying, based upon information contained in the extracted
program multiplex control packet, which portion of each program data
packet in the received subframe is allocated to the selected program, and
for extracting the identified portion from each program data packet.
31. A decoder according to claim 30 wherein the multiplex data stream
contains mapping information that specifies, for each program, which
subframe data stream contains that program, and wherein the superframe
demultiplexer further comprises means for extracting the mapping
information from the received multiplex data stream and identifying
therefrom which subframe in the received superframe contains data for the
selected program.
32. A method comprising the steps of:
a) receiving a plurality of multiplex data streams, each multiplex data
stream containing a multiplexed combination of subframe data streams
wherein each subframe data stream comprises a continuous sequence of
subframes, said received multiplex data streams each having a format
comprising a continuous sequence of superframes, each superframe in a
particular multiplex data stream containing at least one subframe from at
least one of the subframe data streams contained in that multiplex data
stream and each superframe further containing a superframe map that
specifies the location of each subframe within that superframe;
b) for each received multiplex data stream, demultiplexing and separating
the subframe data streams contained in that multiplex data stream and
providing each subframe data stream in a separate channel;
c) selecting a plurality of said demultiplexed and separated subframe data
streams, at least one of said selected subframe data streams having been
demultiplexed and separated from a different multiplex data stream than
others of said selected subframe data streams;
d) multiplexing said selected subframe data streams to generate a new
multiplex data stream having a format comprising a continuous sequence of
superframes wherein each superframe comprises at least one subframe from
at least one of said selected subframe data streams;
e) generating, for each superframe in the new multiplex data stream, a
superframe map that specifies the location of each subframe within that
superframe, and inserting the superframe map in that superframe; and
f) transmitting the new multiplex data stream to at least one reception
site.
33. A method according to claim 32 wherein for each received multiplex data
stream step (b) comprises:
(i) for each successive superframe of the received multiplex data stream,
extracting the superframe map from the superframe, and based upon
information contained therein, locating, extracting and separating the
subframes contained in that superframe; and
(ii) combining each subframe extracted from a particular superframe with
corresponding subframes extracted from previous superframes to reproduce
each subframe data stream and provide each subframe data stream on a
separate channel.
34. A method according to claim 32 wherein each superframe of said new
multiplex data stream and each of said received multiplex data streams has
a format comprising an adjustable number of successive blocks, a first
portion of each block comprising a block synchronization byte (BSYNC), a
second portion of each block comprising a data portion, and a last portion
of each block comprising a block error code generated in accordance with a
block error coding scheme.
35. A method according to claim 32 wherein a first group of blocks in each
superframe of the new multiplex data stream define a superframe transport
layer region of that superframe, and a second group of blocks define a
subframe data region, the superframe map generated in step (c) for each
superframe of the new multiplex data stream being inserted in the
superframe transport layer region of that superframe.
36. A method according to claim 32 further comprising the step of
inserting, in a first block of each superframe of the new multiplex data
stream a superframe synchronization word (FSYNC), and wherein step (e)
comprises inserting the superframe map for each superframe at a location
immediately following the superframe synchronization word.
37. A method according to claim 32 wherein step (f) comprises transmitting
successive superframes of said new multiplex data stream at a constant
rate.
38. A method according to claim 34 wherein each block comprises a
predetermined number of bits, and wherein step (f) comprises transmitting
successive superframes of said new multiplex data stream at a constant
rate such that the new multiplex data stream is transmitted at a bit rate
equal to F.sub.SF (n)(B) bits per second, where F.sub.SF is the rate at
which successive superframes are transmitted, n is the number of blocks in
each superframe, and B is the number of bits in each block.
39. A headend installation comprising:
a plurality of receivers each tuned to receive a different one of a
plurality of multiplex data streams transmitted from at least one encoder
site, each multiplex data stream containing a multiplexed combination of
subframe data streams wherein each subframe data stream comprises a
continuous sequence of subframes, said received multiplex data streams
each having a format comprising a continuous sequence of superframes, each
superframe in a particular multiplex data stream containing at least one
subframe from at least one of the subframe data streams contained in that
multiplex data stream and each superframe further containing a superframe
map that specifies the location of each subframe within that superframe;
a plurality of superframe demultiplexers each coupled to a respective one
of said receivers for demultiplexing and separating the subframe data
streams contained in the multiplex data streams received by that receiver
and for providing each of the separated subframe data stream on a separate
channel;
re-routing means for selecting a plurality of said demultiplexed and
separated subframe data streams, at least one of said selected subframe
data streams having been demultiplexed and separated from a different
multiplex data stream than others of said selected subframe data streams;
and
a superframe multiplexer coupled to receive each of said selected subframe
data streams for multiplexing said selected subframe data streams to
generate a new multiplex data stream, said new multiplex data stream
having a format comprising a continuous sequence of superframes, each
superframe containing at least one subframe from each of said selected
subframe data streams, said superframe multiplexer being further operative
to generate, for each superframe in the multiplex data stream, a
superframe map that specifies the location of each subframe contained in
that superframe, and to insert the superframe map in that superframe.
40. A headend installation according to claim 39 wherein said superframe
multiplexer comprises:
a superframe controller for generating the superframe map for each
superframe; and
a superframe builder coupled to the superframe controller and coupled to
receive successive subframes from each subframe multiplexer for
constructing each superframe in accordance with the superframe map
generated by the superframe controller, and for inserting each superframe
map in its respective superframe.
41. A headend installation according to claim 40 wherein said superframe
multiplexer further comprises an interleaver coupled to an output of said
superframe builder for interleaving portions of each superframe to reduce
burst errors during subsequent transmission of the multiplex data stream
to a remote location.
42. A headend installation according to claim 40 wherein each superframe of
the new multiplex data stream has a format comprising an adjustable number
of successive blocks, a first group of blocks in each superframe defining
a superframe transport layer region of that superframe and a second group
of block defining a subframe data region, said superframe builder
including:
means for inserting a block synchronization byte (BSYNC) in a first portion
of each block; and
means for inserting a superframe synchronization word (FSYNC) in a first
block of each superframe.
43. A headend installation according to claim 42 wherein the superframe
multiplexer further comprises block error coding means for generating a
block error code for each block and appending the block error code to the
block.
44. A headend installation according to claim 39 further comprising a
transmitter coupled to said superframe multiplexer for transmitting
successive superframes of said new multiplex data stream at a constant
rate.
45. A headend installation according to claim 42 wherein each block
comprises a predetermined number of bits, and wherein said headend
installation further comprises a transmitter coupled to said superframe
multiplexer for transmitting successive superframes of said new multiplex
data stream at a constant rate such that the multiplex data stream is
transmitted at a bit rate equal to F.sub.SF (n)(B) bits per second, where
F.sub.SF is the rate at which successive superframes are transmitted, n is
the number of blocks in each superframe, and B is the number of bits in
each block.
46. A headend installation according to claim 39 wherein each superframe
demultiplexer comprises:
a superframe map extractor for locating and extracting a superframe map
from a superframe of the received multiplex data stream, said superframe
map specifying the location of each subframe contained within that
superframe;
a subframe extractor coupled to the superframe map extractor and at least
indirectly responsive to the extracted superframe map for determining the
location of each subframe within the superframe and for extracting and
separating each subframe from the superframe.
47. A digital data stream containing a multiplexed combination of digital
programs wherein each program comprises a combination of related digital
services, said data stream comprising a continuous sequence of
superframes,
each superframe containing a plurality of subframes, and each superframe
containing a superframe map that specifies for that superframe the
location of each of the subframes in that superframe,
each subframe in each superframe containing a multiplexed combination of
data from a subset of said digital programs wherein different portions of
each subframe are allocated to different ones of said programs of said
subset, at least one of the subframes in a particular superframe
containing a multiplexed combination of digital programs from a different
subset than another subframe in that superframe, each subframe further
containing a subframe multiplex map that at least indirectly specifies
which portions of that subframe are allocated to which programs of said
subset.
48. A digital data stream according to claim 47 wherein each subframe in
each superframe has a format comprising a plurality of lines, a first
group of lines in each subframe defining a subframe transport layer region
and a second group of lines defining a program data region, the program
data region of each subframe being portioned into a plurality of program
data packets, and wherein different portions of each program data packet
in each subframe are allocated to different ones of the programs of said
subset.
49. A digital data stream according to claim 48 wherein the transport layer
region of each subframe in each superframe contains a program multiplex
control packet that specifies which portions of each program data packet
in that subframe are allocated to which programs of said subset.
50. A digital data stream according to claim 48 wherein each of said
digital programs has a respective data rate, and wherein different
portions of each program data packet in each subframe are allocated to
different ones of said programs of said subset in proportion to the
respective data rates of said programs of said subset.
51. A digital data stream according to claim 48 wherein the transport layer
region of each subframe in each superframe contains a plurality of system
related data packets including system data packets (SDP's), system
teletext packets (STT's), addressable data packets (ADP's), service seed
packets (SSP's) and program virtual channel map packets (PVCMP's), and
wherein the subframe multiplex map in each subframe specifies the location
of each system related data packet in the transport layer region of that
subframe.
52. A digital data stream according to claim 47 wherein each superframe has
a format comprising an adjustable number of successive blocks, a first
portion of each block comprising a block synchronization byte (BSYNC), a
second portion of each block comprising a data portion, and a last portion
of each block comprising a block error code generated in accordance with a
block error coding scheme.
53. A digital data stream according to claim 52 wherein a first group of
blocks in each superframe define a superframe transport layer region of
that superframe, and a second group of blocks define a subframe data
region, the superframe map of each superframe being located in the
superframe transport layer region of said each superframe.
54. A digital data stream according to claim 53 wherein each subframe has a
format comprising a plurality of lines, and wherein the data portion of
each block in the subframe data region of each superframe contains a
single line of one of the subframes in that superframe.
55. A digital data stream according to claim 52 wherein a first block of
each superframe contains a superframe synchronization word (FSYNC), and
wherein the superframe map for each superframe is located in the
superframe immediately following the superframe synchronization word. |
|
 |
|
 |
Claims |
|
