| 摘要 |
<p>The invention is related to a method and modulator for modulating a digital signal to an analog intermediate-frequency signal. A baseband digital signal (I, Q) is taken to a digital-to-analog converter (71, 710) in which it is sampled at a certain sampling frequency (fin) and converted to an analog signal. The conversion produces a baseband signal (fsig) and signals (N*fin, fNi) at multiples of the sampling frequency (fin). The sampling frequency is increased, advantageously according to a sigma-delta D/A conversion, and one of the signals (N*fin, fNi) at multiples of the sampling frequency (fin), produced by the conversion, is selected as the output signal (fIF), advantageously a multiple (N*fin, fNi) of the sampling frequency that is directly at the intermediate frequency or transmission frequency. <IMAGE></p> |
