Patent ID: 8345799

Claim:
A channel estimating method of performing frequency conversion by a first fast Fourier transformation on a reception signal and extracting a desired signal after demodulating the reception signal, and deriving electrical energy against time delay of a channel by inverse fast Fourier transformation of the extracted result, wherein: values output by a low pass filter that is configured to oversample the reception signal are thinned by a plurality of thinning circuits with the same synchronization and different discrete times, and based on the outputs of the plurality of thinning circuits, the electrical energy against time delay related to the reception signal arrival time position is derived by respectively performing the first fast Fourier transformation and the inverse fast Fourier transformation, wherein, based on the electrical energy, a threshold value is generated from a maximum value or an integrated value of the electrical energy, and threshold processing is performed to leave unchanged values of the electrical energy equal to or greater than the threshold value and to discard values of the electrical energy lower than the threshold value.