Title:
MULTIPOINT DATA MODEM COMMUNICATION SYSTEM
Document Type and Number:
Japanese Patent JPH01155742
Kind Code:
A
Abstract:
PURPOSE: To quicken a start time for a transmission from a remote MODEM by providing a plurality of discrete Fourier transformation filter circuits that measures a correlation between a concerned address frequency and a received signal so as to suppress a remaining address frequency. CONSTITUTION: During the initial training, a terminal 134 of a switch 125 is connected to a timing initial setting circuit 138 having three DFT(discrete Fourier transformation) modules composed of three DFT filter circuits for frequencies 500Hz, 1700Hz and 2900Hz. A receiver control circuit 148 generates receiver parameters related to each other such as an equalizer tap, phase jitter, a frequency shift and a timing deviation and transfers them to a storage device 156. For the succeeding transmission, a transmission MODEM sends the address and a short training signal. Since the related receiver parameters are read out of the storage device 156 in response thereto, the additional training for the control MODEM receiver is not required.
Inventors:
JIYAN BOA
BUIRUHERUMASU JIYOOSEIFUASU MA
BUIRUHERUMASU JIYOOSEIFUASU MA
Application Number:
JP28692688A
Publication Date:
June 19, 1989
Filing Date:
November 15, 1988
Export Citation:
Assignee:
NCR CO
International Classes:
H04B3/10; H04L27/18; (IPC1-7): H04B3/10; H04L11/00; H04L27/18
Attorney, Agent or Firm:
Yoshiaki Nishiyama
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