Electrical computers and digital processing systems: support – Synchronization of clock or timing signals – data – or pulses
Reexamination Certificate
2000-03-30
2004-04-13
Lee, Thomas (Department: 2185)
Electrical computers and digital processing systems: support
Synchronization of clock or timing signals, data, or pulses
C713S600000, C711S167000, C710S052000
Reexamination Certificate
active
06721895
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a data communications system and a data communications method. More to particularly, this invention relates to a data communications system and a data communications method wherein digital communication data is arranged into data packet before being transmitted.
DESCRIPTION OF THE PRIOR ART
In recent years, in the data communications system and the data communications method, it tends to use digital signal. For instance, the AV (Audio-Video) data which had been treated by the user as the analog data in the past. At present, the AV data is treated by the user as the digital data itself. In recent years, the AV data is treated as the digital data itself due to spread of digital satellite broadcast, internet communication, DVD (Digital Video Desk) and so forth. Further, IEEE 1394 high speed serial bus which is capable of transmitting digital data in high speed is made practicable. Thus, it is capable of easily transmitting the AV data with high quality among equipments. It is capable of delivering such the high quality AV data to the user.
A conventional data communications system and a data communications method have a configuration shown in FIG.
1
. The data communications system and the data communications method execute transmission of the data in accordance with timing chart shown in FIG.
2
. Referring to
FIG. 1
, a conventional transmission equipment fundamentally consists of a data acquisition means
210
, a packet controller
220
, a transmission controller
230
, and a physical layer
240
. A conventional reception equipment fundamentally consists of a data processor
250
, a data reception means
260
, a transmission controller
270
, and a physical layer
280
.
These transmission equipment and reception equipment are connected with each other by a transmission line. The data acquisition means
210
acquires the digital AV data through the media (not illustrated), for instance, the broadcast media of the digital satellite broadcast or so forth, the communication media of the internet or so forth, or the storage media such as the DVD or so forth.
The packet controller
220
arranges the above digital AV data into the packet-shaped data (hereinafter referred to as data packet). The transmission controller
230
executes transmission control of the data packet. The physical layer
240
sends out the data packet to the transmission line. The physical layer
280
receives the data packet from the transmission line. The transmission controller
270
implements reception control of the above data packet. The data reception means
260
forms digital AV data while linking these data packets. The data processor
250
executes processing of the digital AV data. Here, the data processing is selection of the digital AV data, demodulation of the digital AV data, D/A conversion of the digital AV data, video display of the digital AV data, audio regeneration of the digital AV data, and so forth. There are two kinds of the transmission modes of the packet transmission in the cases where IEEE 1394 is used for the transmission line. Such the two kinds of transmission modes are an asynchronous type transmission mode for transmitting a control instruction and so forth and a synchronous type transmission mode for transmitting the AV data and so forth, whose transfer band is guaranteed.
In the synchronous type transmission, it is capable of being invariably executed one time of transmission in every one transfer cycle, for instance, in every 125 &mgr;sec. For that reason, the delay time and the transfer band are guaranteed. Thus, it is capable of transmitting the picture and the sound and so forth of real time without quality deterioration.
However, in the data communications method constituted in such the above described conventional technique, there is the problem that when the transmission line is initialized during data communications, the communication is interrupted. For instance, referring to
FIG. 2
, a bus reset occurs on the transmission line, disappearance of the data packet occurs on the transmission line, thus, it is incapable of receiving a part of the data packet on the reception side. Namely, only the picture sources S
1
, S
3
, and S
4
within the picture sources S
1
, S
2
, S
3
, and S
4
are received, and the picture source S
2
can not be received caused by the fact that the picture source S
2
is in the course of occurrence of the bus reset. As a result thereof, when it causes the picture source received by the reception equipment to be processed, the situation occurs that it is incapable of regenerating the picture corresponding to the picture source S
2
. For that reason, the regenerated picture is interrupted.
The proposal for resolving problem in relation to above described bus reset is well known. However, it is incapable of avoiding disappearance of the packet. For instance, the official report of the Japanese Patent Application Laid-Open No. HEI 8-18584 discloses technique that connection information of the equipment maintained beforehand, when the bus reset occurs during data communications, it causes connection of the equipment to be executed again on the basis of the maintained connection information. However, it is incapable of avoiding disappearance of the data packet during the bus reset too.
As is clear from the above description, in the conventional data communications method, there is the problem that a part of the packet is lost during the bus reset.
SUMMARY OF THE INVENTION
In view of the foregoing, it is an object of the present invention, in order to overcome the above mentioned problem, to provide a data communications system and a data communications method which are capable of avoiding disappearance of the digital AV data which is arranged into the data packet.
According to a first aspect of the present invention, in order to achieve the above mentioned object, there is provided a data communications system which comprises an initialized state detector for monitoring state of a transmission line whether or not the transmission line is an initialized state, a data storage means for storing therein an inputted data before outputting the data, and a timing controller, when the initialized state detector detects that the transmission line is under the initialized state, the timing controller causes control instruction to be issued for stopping output of the data temporarily in order to store the data in the data storage means, while when the initialized state detector detects the state that initialized state of the transmission line is released, the timing controller instructs that it causes data including the stored data to be outputted, wherein the data communications system enables disappearance of the transmit data to be prevented, which disappearance of the transmit data occurs caused by temporal interruption condition according to initialization of the transmission line.
Consequently, it is capable of preventing disappearance of the transmit data. The disappearance of the transmit data occurs caused by temporal interruption condition according to initialization of the transmission line.
According to a second aspect of the present invention, in the first aspect, there is provided a data communications system, which further comprises a data acquisition means for acquiring data from storage medium such as a DVD, a hard disk or the like and/or data medium such as an internet or the like, a packet controller for arranging data acquired by the data acquisition means into a data packet, and a transmission controller for controlling transmission of the data which is made the data packet by the packet controller, wherein, as to a communication means using a packet switching system to be efficient in data transmission, the data communications system enables disappearance of the transmit data to be prevented, which disappearance of the transmit data occurs caused by temporal interruption condition according to initialization of the transmission line.
Consequently, in the communication means usi
Connolly Mark
Dickstein Shapiro Morin & Oshinsky LLP.
Lee Thomas
LandOfFree
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