| 摘要 |
<p>It is an object of the present invention to provide a method and an apparatus for multi-level quadrature amplitude modulation system, in which the DC level of the output is "0" even when the modulation multi-level number is varied and mean electric power becomes almost the same, and the multi-level quadrature amplitude modulation system of the present invention is capable of modulating at different modulation multi-level numbers and comprises the steps of converting all of the input bit numbers into the same bit number based on a prescribed conversion rule for each orthogonal channel irrespective of the modulation multi-level number of the multi-level quadrature amplitude modulation system, filtering the converted signal by means of a digital filter, converting the output of the digital filter into an analog signal by means of a D/A converter, and modulating the analog signal by means of a quadrature modulator. <IMAGE></p> |
