PURPOSE: To improve a ratio of transmission power to a maximum amplitude by providing an amplitude limiter to improve the ratio of effective power to the maximum amplitude.
CONSTITUTION: A data conversion circuit 1, 2 being an amplitude limiter is connected between the output of a real number part and imaginary number part of a FET circuit 51 and an input of a D/A converter circuit 52, 53. The circuit 1, 2 executes a predetermined amplification and amplitude limit to a real part (imaginary part) of the output of the FET circuit 51. The FET circuit 51 receiving digital modulation data executes inverse Fourier transformation to output the real number part and imaginary number part as time waveform sample series. The conversion circuits 1, 2 limit the large amplitude portion and amplifies a small amplitude portion without distortion and the D/A converter circuits 52, 53 convert the data into analog signal data. The data are inputted to an orthogonal transformation circuit 57 via LPFs 54, 55 eliminating a loopback signal and the circuit 57 multiplies a signal from a local oscillator 56 to provide an output of an IF band OFDM signal 58.
HAMAGUCHI YASUHIRO
MIYAZAKI MASAO
OTA TOMOZO
