| US 7,593,425 B2 | ||
| Signal distribution method and a signal distribution apparatus | ||
| Yoshiyuki Karakawa, Yokohama (Japan); Masaki Bansho, Yokohama (Japan); Yuji Kuroki, Yokohama (Japan); Junichi Kawaguchi, Yokohama (Japan); Koji Hachiya, Yokohama (Japan); and Satoru Saitoh, Kawasaki (Japan) | ||
| Assigned to Fujitsu Limited, Kawasaki (Japan) | ||
| Filed on Jul. 08, 2004, as Appl. No. 10/887,471. | ||
| Application 10/887471 is a continuation in part of application No. PCT/JP03/14521, filed on Nov. 14, 2003. | ||
| Claims priority of application No. 2004-175719 (JP), filed on Jun. 14, 2004. | ||
| Prior Publication US 2005/0117608 A1, Jun. 02, 2005 | ||
| Int. Cl. H04J 3/16 (2006.01); H04J 3/00 (2006.01); G01R 31/08 (2006.01) | ||
| U.S. Cl. 370—466 [370/229; 370/474; 370/476] | 9 Claims |
| 1. A signal distribution method by which transport packets of a television signal that is multiplexed with a plurality of
channels are supplied in a transmission format of a digital broadcasting standard, and said transport packets are transmitted
and distributed over a synchronous network, the signal distribution method comprising:
setting a transmission rate in said synchronous network according to the number of the multiplexed channels for each customer,
said setting comprising:
extracting transport packets and space codes and writing the extracted transport packets and predetermined space codes in
a first buffer;
converting the transport packets read from the first buffer into a superblock and writing the superblock into a second buffer;
reading the superblock from the second buffer and performing a Generic Framing Protocol (GFP) mapping to map said superblock
onto GFP frames; and
discarding the transport packets supplied for a customer when a transmission rate thereof exceeds the transmission rate in
the synchronous network set for said customer by prohibiting writing of the transport packets to the first buffer when an
amount of the superblock written in the second buffer exceeds a threshold value,
said converting comprising:
converting a predetermined number of the transport packets into the superblock if a byte count of said transport packets written
in the first buffer is said predetermined number or greater;
suspending conversion to the superblock for a predetermined period if the byte count of said transport packets is less than
said predetermined number; and
converting the transport packets into the superblock if the byte count remains less than said predetermined number after a
lapse of said predetermined period by adding PAD control codes such that the byte count becomes equal to the predetermined
number.
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