Patent ID: 8847751

Claim:
A communication apparatus for carrying out data transmission by use of a pair of conductors, comprising: a line status detection apparatus configured to detect a balance status of the pair of conductors, the line detection apparatus comprising a signal transmission section which transmits a reference timing signal, a pilot signal, and a transmission signal to another communication apparatus through said pair of conductors, the signal transmission section transmits the pilot signal between the reference timing signal and the transmission signal, a signal level of said pilot signal being known an unbalance component detection section which detects an unbalance component between said conductors, the unbalance component indicating the balance status of the pair of conductors, based on said pilot signal transmitted to said pair of conductors by said signal transmission section, a transmission control section which controls said transmission signal based on said unbalance component detected by said unbalance component detection section so as to reduce said unbalance component of said pair of conductors, a time-frequency transformation section which calculates a signal level of said unbalance component detected by said unbalance component detection section, on a frequency domain, through the use of time-frequency transformation, a signal level estimation section which estimates a signal level of an estimated unbalance component which is not calculated by said time-frequency transformation section, by use of a signal level of the unbalance component calculated by the time-frequency transformation section, and a wave form generation section which generates a multi-carrier communication signal, on the basis of the signal level of estimated unbalance component estimated by said signal level estimation section; wherein said communication apparatus transmits multi-carrier communication signals, and said signal level estimation section estimates a signal level of said estimated unbalance component, around a notch band in which a predetermined carrier is not transmitted, by use of the signal level of the unbalance component calculated by said time-frequency transformation section.