| 摘要 |
According to the present method, the audio signal AS to be transmitted under SSB is sampled SH, digitised ADC, filtered by means of a complex filter CF carrying out rejection of the undesired side band, the coefficients of the filter determining the selection of the upper or lower band. Then the real part (channel I) and the imaginary part (channel Q) of the complex signal are converted (DACI, DACQ respectively) to analogue, shifted (MI, MQ respectively) to the frequency of transmission on the two quadrature channels and recombined AD by addition to give the modulated signal SSB within the desired side band. The purely digital functions can be carried out advantageously by a signal processor capable of working in complex mode. Application: SSB or LLB signal modulation. <IMAGE>
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