Ring network and data transmitter

• US 20040088436A1
• Filed: 04/04/2003
• Published: 05/06/2004
• Est. Priority Date: 10/05/2000
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Mizuguchi, Yuji, Katta, Noboru, Yasui, Nobuhiko, Takahira, Yutaka, Sakai, Takahisa, Kawada, Hirotsugu, Kurosaki, Toshihiko
• Granted Patent: US 7,133,936 B2
• Time in Patent Office: Days
• US Class Current: 709/248
• CPC Class Codes: H04L 25/062 Setting decision thresholds using feedforward techniques only
• CPC Class Codes: H04L 25/066 Multilevel decisions, not including self-organising maps
• CPC Class Codes: H04L 25/085 Arrangements for reducing interference in line transmission systems, e.g. by differential transmission
• CPC Class Codes: H04L 25/4919 using balanced multilevel codes H04L25/4927 takes precedence

Abstract

It is an object to provide a ring-shaped network which can speedily perform initialization even when a plurality of data transmission apparatuses, each performing multi-valued transmission while assigning one or more bits of data as one data symbol to a signal level, are connected thereto, and a data transmission apparatus.

The data transmission apparatus outputs received data to a device connected thereto while performing establishment of clock synchronization on the basis of the received data, and when synchronization is established, it resends the received data. On the other hand, when synchronization of the connected device is established, it sends data supplied from the connected device. Further, in the ring-shaped network, a master data transmission apparatus outputs data at turn-on of power or immediately after reset, and a next-stage slave data transmission apparatus receives the data to establish synchronization, and resends the received data when synchronization is established. Thus, synchronization of all the data transmission apparatuses is established while making a round of this data, and then synchronization of devices connected to the respective data transmission apparatuses is established.

Claims

1. (Amended) A ring-shaped network in which plural data transmission apparatuses, each performing data transmission while assigning one or more bits of data as one data symbol to a signal level, are connected via a transmission path, wherein

one of the data transmission apparatuses is a master data transmission apparatus, while the other data transmission apparatuses are slave data transmission apparatuses;

each of the data transmission apparatuses is connected with a device which is supplied with data received by the data transmission apparatus, and outputs a result of processing to the data transmission apparatus;

at turn-on of power or immediately after reset, the master data transmission apparatus outputs the data supplied from the connected device, to the transmission path;

each of the slave data transmission apparatuses receives, from the transmission path, the data outputted from the data transmission apparatus connected in the previous stage, establishes clock synchronization, outputs the received data to the connected device, and resends the received data to the transmission path; and

the slave data transmission apparatus outputs the data supplied from the connected device, to the transmission path, after synchronization of the connected device is established.

2. A ring-shaped network as defined in claim 1, wherein the slave data transmission apparatus does not output the data to the transmission path until establishment of clock synchronization is completed.

3. A data transmission apparatus which is connected to a ring-shaped network via a transmission path, and performs data transmission while assigning one or more bits of data as one data symbol to a signal level;

said data transmission apparatuses being connected with a device which is supplied with data received by the data transmission apparatus, and outputs a result of processing to the data transmission apparatus; and

said data transmission apparatus including;

a synchronization detector for establishing synchronization on the basis of the data inputted through the transmission path, and performing reproduction of a data clock;

a connected device synchronization detector for detecting that synchronization of the connected device is established; and

a selector for switching data to be transmitted to the transmission path between the data received through the transmission path and the data supplied from the connected device.

4. A data transmission apparatus as defined in claim 3, wherein said connected device synchronization detector receives the data supplied from the connected device, and reproduces a device clock that is synchronized with the data.

5. A data transmission apparatus as defined in claim 3 or claim 4, wherein

said connected device synchronization detector receives the data supplied from the connected device, and detects a data frame including the data, thereby to detect that synchronization of the connected device is established.

6. A data transmission apparatus as defined in claim 3, wherein

said connected device synchronization detector counts the clock that is inputted in synchronization with the data supplied from the connected device, and the data clock that is reproduced by the synchronization detector on the basis of the data received through the transmission path, for a predetermined period of time, thereby to detect that synchronization of the connected device is established.

7. A data transmission apparatus as defined in claim 4, wherein

said connected device synchronization detector counts the device clock that is reproduced from the data supplied from the connected device, and the data clock that is reproduced by the synchronization detector on the basis of the data received through the transmission path, for a predetermined period of time, thereby to detect that synchronization of the connected device is established.