| 摘要 |
PROBLEM TO BE SOLVED: To impose digital orthogonal modulation on an information quantity at a sampling frequency which is a half as high as before and to perform transmission by converting four pieces of output data of a shift register from digital to analog at the frequency which is a twice as high as the sampling frequency and outputting 2N pieces of digital orthogonally modulated data. SOLUTION: A conversion output of an inverse fast Fourier transformation(IFFT) part 13 is rearranged by an Even/Odd data selector 14 so that even trains and odd trains are outputted at the same time, and the rearranged signal trains are outputted at a sampling frequency Fs/2. Then the output data are supplied to and processed by a multiplier 15 and then supplied to a shift register 16. Four pieces of output data of the shift register 16 are inputted to a data selector 17, takes out of the data selector 17 on order at the frequency twice as high as the sampling frequency, and converted by a D/A conversion part 18 at the frequency twice as high as the sampling frequency Fs, so that 2n pieces of digital orthogonally modulated data are outputted.
|
