| 摘要 |
PROBLEM TO BE SOLVED: To continuously obtain a clock signals without adding special synchronous information at a sending side and without utilizing an FET operation result at a receiving side by generating a symbol timing clock from a residual high frequency component, performing phase comparison between the both signals of the generated clock and the symbol clock ad controlling an output frequency of a voltage control oscillating means according to the comparison result. SOLUTION: An input orthogonal frequency division multiple OFDM modulation wave is demodulated by multipliers 1 and 2, digitized by A/D converters 3 and 4 and successively processed and demodulated by a guard interval processor 5, an FET.QAM decoder 6 and an output circuit 7. A phase difference detector 8 calculates the phase difference of each carrier from the operation result of the decoder 6, a D/A converter 9 converts the result into an analog value, a loop filter 10 eliminates unneeded noise and a voltage control oscillator 12 which outputs a carrier frequency is controlled. An output of the oscillator 12 is supplied to the multiplier 1 through 90 degree phase shifter 13. |
