Title:
【発明の名称】データ通信方式
Document Type and Number:
Japanese Patent JP2702303
Kind Code:
B2
Abstract:
At the transmit end of a communications system, a convolutional code of a multiplex of an information-bearing signal and a unique word is modulated upon a transmitted carrier. At the receive end, the transmitted carrier is demodulated with a local carrier to detect the convolutional code. The error rate of a decoded version of the convolutional code is determined, and an out-of-FEC-sync signal is produced when the error rate is higher than a threshold value. Unique words are detected from the decoded signal and counted during a prescribed time interval to produce an out-of-frame-sync signal when the count falls below a threshold. The frequency of the local carrier is swept in the presence of the out-of-FEC-sync signal. When this signal ceases to exist, a timeout period is set, and the local carrier frequency is swept again when the timeout period expires during the presence of the out-of-frame-sync signal.
Inventors:
Youzo Hirata
Hide Nawata
Hide Nawata
Application Number:
JP8159191A
Publication Date:
January 21, 1998
Filing Date:
March 20, 1991
Export Citation:
Assignee:
NEC
NEC Engineering Co., Ltd.
NEC Engineering Co., Ltd.
International Classes:
H04L1/00; H04L27/227; H04L7/04; H04L27/00; (IPC1-7): H04L1/00
Domestic Patent References:
| JP6410749A | ||||
| JP60213135A | ||||
| JP1309431A | ||||
| JP1311739A |
Attorney, Agent or Firm:
Hachiman Yoshihiro