To prevent erroneous detection of an unbalanced component of a carrier adjacent to a notch band when there is the notch band which does not transmit any carrier, in the case of analyzing frequency characteristics of the unbalanced component in a transmission line for performing multicarrier communication.
A common-mode current generated in a power line 10 used as a transmission line is detected by an unbalanced component detection unit 21, the number of points of a FFT (Fast Fourier Transform) is reduced by half by an FFT preprocessing unit 23, the FFT is then performed by a FFT unit 24, and frequency characteristics of the unbalanced component corresponding to a plurality of carriers of multicarrier communication data are calculated. A level estimation unit 25 determines a maximum value or an average value of N+a detected carriers of which the unbalanced components are calculated by the FFT, and defines the value as a level estimate M of unbalanced components in the N detected carriers and in non-detected carriers of which the unbalanced components are not calculated, among the detected carriers. A waveform generation unit 31 performs transmission level control of carriers using the level estimate M.
MATSUNOBU HIDEKAZU
IGATA YUJI
WAKIZAKA TOSHIYUKI
KUSUNE KAZUAKI
| JPH02261232A | 1990-10-24 | |||
| JP2000165304A | 2000-06-16 | |||
| JPS62107538A | 1987-05-18 | |||
| JP2004260774A | 2004-09-16 |
Toshimitsu Ichikawa
Kimihide Hashimoto