ORTHOGONAL FREQUENCY DIVISION/MULTIPLEX MODULATION SIGNAL TRANSMITTING SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide an orthogonal frequency division multiplex modulation signal transmitting system which can precisely detect the shift quantity of a carrier frequency and synchronously pulls it in even if frequency fluctuation exceeding the frequency interval of a carrier exists. SOLUTION: A CW insertion place securing circuit 15 and a CW insertion circuit 16 are provided on a transmission device-side and a CW symbol being a special symbol wherein only one carrier has a signal is inserted at every prescribed period. A CW extraction circuit 17 and an adjusting circuit 10 are provided on a reception device-side. The carrier frequency shiftΔFL of the orthogonal frequency division/multiplex(OFDM) signal of a base band is calculated and the oscillation frequency fr of a reception side local oscillator 9 is controlled by using the values of the complex vector signals Zcw(n) of plural carriers obtained by discrete Fourier transformation. Thus, an inexpensive and small oscillator whose fluctuation width of the oscillation frequency exceeds a carrier frequency interval can be used as the local oscillator on a transmission side and a reception side.