To suppress a
demodulation error rate while utilizing a fractional
spreading factor in LoRa modulation.SOLUTION: A demodulator (30) comprises a sampling unit (302), a correction unit (306), an
estimation unit (307), and an output unit (308). The sampling unit performs
oversampling on a received
signal subjected to FSF-LoRa modulation that uses a predetermined
spreading factor and a predetermined fractional coefficient, at a sampling interval obtained by dividing a
chip length used in the FSF-LoRa modulation by a predetermined
oversampling coefficient, thereby generating an equivalent low-pass
signal. The correction unit (306) performs correction, which is based on the
spreading factor, the fractional coefficient and the
oversampling coefficient, on a de-spread DFT
signal obtained by performing de-spreading
processing and DFT
processing on the equivalent low-pass signal, thereby generating a correction signal. The
estimation unit (307) estimates a frequency index having a
maximum amplitude among a plurality of frequency indices included in the correction signal as an index of a desired signal.SELECTED DRAWING: Figure 3