Patent ID: 7751351

Claim:
A disturbing signal detecting device in which a plurality of carriers having frequencies orthogonal to each other in a transmission band are modulated with allocated information signal, the device receives an OFDM transmission signal with a known pilot signal periodically inserted for the plurality of carriers modulated with the information signal, and detects a disturbing signal included in the signal received, comprising: an IFFT computing unit for performing an IFFT computation for a transmission line characteristic calculated from the pilot signal; a threshold processing part that compares a time-base signal obtained as a result of an IFFT computation by the IFFT computing unit, with a threshold, and if the time-base signal exceeds the threshold, substitutes zero for a value of the signal; an FFT computing unit that performs an FFT computation for the signal processed by the threshold processing part and converts to a frequency-base signal; an interference detector that interpolates timewise and frequencywise the frequency-base signal obtained from the FFT computing unit, and calculates a disturbing signal added to an OFDM signal band; a windowing part that multiplies the transmission line characteristic calculated from the pilot signal, by a window function; and an inverse windowing part that multiplies the frequency-base signal obtained from the FFT computing unit, by an inverse number of the window function multiplied in the windowing part.