| 摘要 |
PURPOSE: A process and a device are provided to directly modulate an RF carrier with a quadrature signal by using amplitude and phase error compensation. CONSTITUTION: The correction operations is performed at a DSP processor(501) level. The inputs and outputs of the signals of the DSP are effected by way of analogue/digital and digital/analogue converters. In this processor, the useful signals are generated in a known coding system(502) and then sent to a generator of the signals I and Q(503) which simultaneously performs the modulation error correction on the basis of an error signal obtained in the manner described hereinbelow. The signals I and Q, which are in baseband, are then filtered in a filtering module(504) so as to obtain the spectrum. An LF(Low-Frequency) reference subcarrier is generated by a generator(505). It is then inserted with the aid of a switch(506) alternately into the signals I and Q by summators(507,508). The tempo is determined by a clock signal delivered by a sequencer(522), so as to obtain the desired compensation tempo.
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