Pulse or digital communications – Bandwidth reduction or expansion – Television or motion video signal
Reexamination Certificate
2000-10-17
2004-01-13
Rao, Andy (Department: 2613)
Pulse or digital communications
Bandwidth reduction or expansion
Television or motion video signal
C375S240260, C375S240270, C341S050000, C341S058000, C348S464000, C348S476000, C348S500000, C348S521000, C348S525000
Reexamination Certificate
active
06678333
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to method of and apparatus for transmitting digital data, and more particularly, is directed to improvements in a digital data transmitting method by which 8-bit word sequence data including word synchronous data are produced for representing various image information such as information of digital luminance and chrominance signals constituting a digital video signal and converted into serial digital data to be transmitted through a data transmission line and in a digital data transmitting apparatus used for putting the above-mentioned method into practice.
2. Description of the Prior Art
In the field of data transmission in which digital data containing information data representing various signal information are transmitted, an electric transmission system and an optical transmission system have been proposed to be put into practice. In the case of the electric transmission system, the digital data are converted into one or more electric signals to be transmitted through one or more transmission lines each made of a coaxial cable or a pair of twisted lines. In the case of the optical transmission system, the digital data are converted into one or more optical signals to be transmitted through one or more transmission lines each made of an optical fiber cables. The formats of the digital data are classified broadly into two categories, one of which is an STM (Synchronous Transfer Mode) format in which a constant frame period is set and the other of which is an ATM (Asynchronous Transfer Mode) format in which a constant frame period is not set.
The current digital networks, in which the digital data transmission systems as mentioned above have been adopted, have developed on the basis of telephone line networks. Data multiplexing for actualizing highly efficient data transmission and broad-band signal transmission at high speed based on data to be transmitted are inevitably required to the information transmission through the digital networks with the developments thereof. Accordingly, the technology called SDH (Synchronous Digital Hierarchy) been established by the ITU-T (former CCIR) the technology called SDH (Synchronous Digital Hierarchy) as one of systems for multiplexing data to be converted into high speed and broad-band signals and transmitting the high speed and broad-band signals thus obtained.
The SDH has proposed a new STM format with synchronous multiplexing structure including a basic unit called STM-
1
, which is fit for high speed and broad-band signal transmission services in future. The STM-
1
is a transmission signal with a period composed of 9 rows, each of which is composed of a data section of 270 bytes (1 byte=8 bits), that is, 270 bytes×9=2,430 bytes, as shown in FIG.
1
. This unit periodic segment of 2,430 bytes is called a frame. The first 9 bytes in 270 bytes contained in each of the 9 rows constituting each frame form a portion of a section overhead (SOH) and AU pointer. The rest 261 bytes in 270 bytes contained in each of the 9 rows form an information data area.
The portion of the section overhead and AU pointer is composed of 9 byte×9=81 bytes including A
1
, A
2
, B
1
, B
2
, C
1
, D
1
~D
12
, E
1
, E
2
, F
1
, K
1
, K
2
, H
1
, H
2
, H
3
, Z
1
and Z
2
each representing 1 byte. These bytes have their respective contents as shown in FIG.
1
. Each of A
1
and A
2
(frame pattern) is an 8-bit word synchronous data and three successive A
1
s at the beginning portion of the first row and three successive A
2
s following the three successive A
1
s in the first row form a synchronous pattern in each frame. The A
1
which is the 8-bit word synchronous data is allotted a specific code of 11110110 and the A
2
which is also the 8-bit word synchronous data is allotted another specific code of 00101000.
The period of the STM-
1
is determined to be, for example, 125 &mgr;s. Consequently, the transmission capacity of the STM-
1
is calculated to be 270 bytes×9×{fraction (1/125)}×10
−6
seconds×8=155.520 Mbit/s (155.520 Mbps).
There has been further proposed a high speed data transmission in which of transmission signals each functioning as the STM-
1
are multiplexed. The transmission signal thus obtained by multiplexing is called STM-N. The STM-N is formed, for example, by multiplexing transmission signals STM-
1
#1, STM-
1
#2, . . . , STM-
1
#n, each functioning as the STM-
1
, in the manner of byte-intreleaving at a data multiplexing portion MP, as shown in FIG.
2
.
The high speed data transmission service called SONET (Synchronous Optical Network) in the United States of America has been generally known as a communication service to which the SDH as aforementioned is practically applied.
In the field of video signals, digitalization of video signals has been aimed for actualizing diversification in information transmission, improvements in quality of reproduced images based on video signals and so on. For example, there has been proposed the High Definition Television (HDTV) system which uses a digital video signal representing video signal information. The digital video signal under the HDTV system (hereinafter, referred to an HD digital video signal) is formed, for example, in accordance with such data formats as shown in
FIGS. 3A and 3B
.
The data formats shown in
FIGS. 3A and 3B
include a luminance signal data sequence (Y data sequence) as shown in
FIG. 3A
, which represents a luminance signal component of a video signal, and a color difference signal data sequence (P
B
/P
R
data sequence) as shown in
FIG. 3B
, which represents color difference signal components of the video signal. Each of data words constituting the Y data sequence or the P
B
/P
R
data sequence is composed of 10 bits. Namely, each of the Y data sequence and the P
B
/P
R
data sequence is formed into 10-bit word sequence data. A part of the Y data sequence which includes a portion corresponding to a horizontal blanking period and parts of portions corresponding to a couple of video data periods appearing before and after the horizontal blanking period in a horizontal period of the Y data sequence is shown in FIG.
3
A. Similarly, a part of the P
B
/P
R
data sequence which includes a portion corresponding to a horizontal blanking period and parts of portions corresponding to a couple of video data periods appearing before and after the horizontal blanking period in a horizontal period of the P
B
/P
R
data sequence is shown in FIG.
3
B.
In the Y data sequence, time reference code data SAV (Start of Active Video) which are composed of four 10-bit words (3FF(Y), 000(Y), 000(Y), XYZ(Y): 3FF and 000 are hexadecimal numbers and (Y) indicates a word contained in the Y data sequence) are provided just before a portion corresponding to the video data period and another time reference code data EAV (End of Active Video) which are composed of four 10-bit words (3FF(Y), 000(Y), 000(Y), XYZ(Y)) are provided just after the portion corresponding to the video data period. Similarly, in the P
B
/P
R
data sequence, time reference code data SAV which are composed of four 10-bit words (3FF(C), 000(C), 000(C), XYZ(C): 3FF and 000 are hexadecimal numbers and (C) indicates a word contained in the P
B
/P
R
data sequence) are provided just before a portion corresponding to the video data period and another time reference code data EAV which are composed of four 10-bit words (3FF(C), 000(C), 000(C), XYZ(C)) are provided just after the portion corresponding to the video data period. The time reference code data EAV and SAV contained in the Y data sequence are provided in a portion corresponding to the horizontal blanking period of the Y data sequence and the time reference code data EAV and SAV contained in the P
B
/P
R
data sequence are provided in a portion corresponding to the horizontal blanking period of the P
B
/P
R
data sequence.
When the Y data sequence and the P
B
/P
R
data sequence are transmitted, the Y
Kessler Gordon
Parsons Charles E
Rao Andy
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