公开(公告)号：JP2001103126A

公开(公告)日：2001-04-13

申请号：JP2000249208

申请日：2000-08-21

Applicant: LUCENT TECHNOLOGIES INC

Inventor： JONATHAN HELLMAN FISHER ,  LATURELL DONALD R ,  RENE A SMITH ,  STEVEN BURUUKU WITTOMAA

IPC: H04M1/00 ,  H04L25/03 ,  H04M1/738 ,  H04M19/08

Abstract: PROBLEM TO BE SOLVED: To eliminate the occurrence of an error due to a DC offset in an analog circuit caused when a DC line current of a telephone line is adjusted. SOLUTION: The method and the system are to adjust a DC line current in a telephone line and to reduce the quantity of errors introduced to a system. Compensating a DC error component introduced by an A/D converter having a DC offset can reduce the error. A software program can limit the DC error according to predetermined parameters through digital control of the DC offset. The predetermined parameters are selected to cover specifications in various countries in place of a switch controlling resistors and capacitors. Furthermore, even when a standard of a country is changed, the software program can cope with the change in place of replacing components or redesigning a printed circuit board.