Initializing method and data transmitter

• US 7,012,936 B2
• Filed: 10/05/2001
• Issued: 03/14/2006
• Est. Priority Date: 10/05/2000
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Patel, Ajit
• Application Number:
  US10/398,452
• Publication Number:
  US 20040042542A1
• Time in Patent Office: 1,621 Days
• Field of Search: 370/503, 370/515, 370/509, 370/510, 370/511, 370/512, 370/513, 370/514, 375/354, 375362-368
• US Class Current: 370/503
• CPC Class Codes: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• 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
• CPC Class Codes: H04L 7/046 using a dotting sequence
• CPC Class Codes: H04L 7/10 Arrangements for initial synchronisation

Abstract

A first initialization pattern signal is a signal in which a maximum signal level and a minimum signal level appear alternately, and a second initialization pattern signal is a signal in which all signal levels appear in a predetermined arrangement. In a ring-shaped network including plural stages of data transmission apparatuses (100), a transmission unit (110) of each data transmission apparatus outputs the first initialization pattern signal successively to a next-stage data transmission apparatus at turn-on of power or immediately after reset, and a reception unit (120) establishes clock synchronization on the basis of the first initialization pattern signal received. When synchronization is established in all of the data transmission apparatuses, the transmission unit (110) outputs the second initialization pattern signal successively to the next-stage data transmission apparatus, and the reception unit (120) sets evaluation levels for the respective signal levels on the basis of the received second initialization pattern signal, and transmission/reception of data is started when evaluation levels are set in all of the data transmission apparatuses.

Claims

1. An initialization method for use in a ring-shaped network comprising a plurality of stages of data transmission apparatuses, each performing data transmission while assigning one or more bits of data as one data symbol to a signal level, one data transmission apparatus being a master data transmission apparatus, any remaining data transmission apparatuses being slave data transmission apparatuses, said initialization method comprising:

outputting a first initialization pattern signal from the master data transmission apparatus to a slave data transmission apparatus in a next stage upon turn-on of power or immediately after reset;

establishing clock synchronization via the next-stage slave data transmission apparatus upon receipt of the first initialization pattern signal;

outputting the first initialization pattern signal from the next-state slave data transmission to a slave data transmission apparatus in the following stage when clock synchronization is established;

outputting a second initialization pattern signal from the master data transmission apparatus to the next-stage slave data transmission apparatus after outputting the first initialization pattern signal;

setting an evaluation level for each signal level via the next-stage slave data transmission apparatus when the next-stage slave data transmission apparatus receives the second initialization pattern signal;

outputting the second initialization pattern signal from the next-stage slave data transmission apparatus to the slave data transmission apparatus in the following stage; and

starting transmission/reception of data in the data transmission apparatuses connected in the ring-shaped network after establishing the evaluation levels.

2. An initialization method as defined in claim 1, wherein said outputting a second initialization pattern signal from the master data transmission apparatus comprises outputting a signal in which a PN pattern is assigned to data symbols.

3. An initialization method as defined in claim 2, wherein said outputting a first initialization pattern signal from the master data transmission apparatus comprises outputting a signal in which a signal for discriminating between the first initialization pattern signal and the second initialization pattern signal appears at the end.

4. An initialization method as defined in claim 2, wherein said outputting a second initialization pattern signal from the master data transmission apparatus comprises outputting a signal in which a signal for discriminating between the first initialization pattern signal and the second initialization pattern signal appears at the beginning.

5. A data transmission apparatus which is connected in a ring-shaped network, and is operable to perform data transmission while assigning one or more bits of data as one data symbol to a signal level, said data transmission apparatus comprising:

a first initialization pattern output unit operable to output a first initialization pattern signal for establishing clock synchronization to a data transmission apparatus connected in a next stage of the ring-shaped network;

a second initialization pattern output unit operable to output a second initialization pattern signal for setting an evaluation level by which the signal level is subjected to threshold evaluation, to the data transmission apparatus connected in the next stage of the ring-shaped network; and

a synchronization establishment unit operable to receive the first initialization pattern signal transmitted from a data transmission apparatus connected in a previous stage of the ring-shaped network, and to perform clock reproduction to establish synchronization,

wherein said data transmission apparatus is operable to start transmitting/receiving data after synchronization is established on receipt of the first initialization pattern signal, and

wherein said data transmission apparatus is operable to set evaluation levels of data upon receipt of the second initialization pattern signal.

6. A data transmission apparatus as defined in claim 5, wherein said data transmission apparatus is a master data transmission apparatus in which said first initialization pattern output unit is operable to output the first initialization pattern signal at turn-on of power or immediately after reset, and

wherein said second initialization pattern output unit is operable to output the second initialization pattern signal when synchronization is established.

7. A data transmission apparatus as defined in claim 5, wherein said data transmission apparatus is a slave data transmission apparatus in which said first initialization pattern output unit is operable to output the first initialization pattern signal when synchronization is established, and

wherein said second initialization pattern output unit is operable to output the second initialization pattern signal when the beginning of the second initialization pattern signal is received.