公开(公告)号：DE68915274T2

公开(公告)日：1994-11-10

申请号：DE68915274

申请日：1989-07-12

Applicant: IBM

Inventor： CHEVILLAT PIERRE RENE ,  ELEFTHERIOU EVANGELOS ,  MAIWALD DIETRICH G U ,  QUINTIN MICHEL

IPC: H04L7/10 ,  H04J3/06 ,  H04L27/18 ,  H04L27/22 ,  H04L27/34 ,  H04M11/00

Abstract: In a data transmission wherein a transmitting modem transmits data signals to a receiving modem via a telephone line, the process of the invention consists in rotating (12), in the transmitting modem, the phase of the point of the constellation resulting from a group of data bits by a predetermined phase value, and then rotating (22) after, a predetermined delay in the receiving modem, the phase of the estimated point resulting from the transformation of the analog signal, by the opposite of said predetermined phase value, the mean-square error between the rotated point and the estimated point of the constellation being used to determine whether the receiving modem is out of synchronization or not.

公开(公告)号：DE68915274D1

公开(公告)日：1994-06-16

申请号：DE68915274

申请日：1989-07-12

Applicant: IBM

Inventor： CHEVILLAT PIERRE RENE ,  ELEFTHERIOU EVANGELOS ,  MAIWALD DIETRICH G U ,  QUINTIN MICHEL

IPC: H04L7/10 ,  H04J3/06 ,  H04L27/18 ,  H04L27/22 ,  H04L27/34 ,  H04M11/00

Abstract: In a data transmission wherein a transmitting modem transmits data signals to a receiving modem via a telephone line, the process of the invention consists in rotating (12), in the transmitting modem, the phase of the point of the constellation resulting from a group of data bits by a predetermined phase value, and then rotating (22) after, a predetermined delay in the receiving modem, the phase of the estimated point resulting from the transformation of the analog signal, by the opposite of said predetermined phase value, the mean-square error between the rotated point and the estimated point of the constellation being used to determine whether the receiving modem is out of synchronization or not.