摘要 |
Multiple carriers are generated, modulated by data to be transmitted, as shown by oscillators and modulators (or using Fourier transform techniques). They follow two paths. One path via an adder takes a set of carriers at integer multiples of a windowing frequency where the odd carriers have some reference phase and the even carriers are in phase quadrature. The other path via an adder takes a second set of carriers, again at integer multiples of the windowing frequency. The even carriers have a reference phase and the odd carriers are in phase quadrature therewith. In the first path, the signal is multiplied by a windowing function with a period equal to the reciprocal of the windowing frequency. In the second path, the signal is multiplied by a similar function which is time-shifted (by a delay) by half of the period.
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