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本文从功率效率和带宽效率两个方面,对量化脉冲位置调制体制(QPPM调制体制)进行粗浅地探讨,并给出了相干检测方式,QPPM调制体制的误字概率公式和带宽效率公式。分析结果表明,QPPM调制体制在小信息率传输情况下,对某些带宽不受限的理想信道,可以获得一定的功率效果。但是,小信息率传输不仅与当前日益发展的大容量要求不相容,况且带宽不受限的理想信道实际上也不存在。因此,工程上运用QPPM调制体制非但得不到功率效率提高的长处,反而较之当前普遍采用的最佳体制也稍有逊色。或许这就是QPPM调制体制在国内外通信、卫星通信、遥测中得不到采用的原因。
In this paper, we discuss the QPM (pulse position modulation) system in terms of power efficiency and bandwidth efficiency, and give the coherence detection method, the error probability formula and the bandwidth efficiency formula of the QPPM modulation system. The analysis results show that the QPPM modulation system can obtain certain power effect for some ideal channels with limited bandwidth under small information rate transmission. However, the transmission of small information rates is not only incompatible with the current growing demand for large capacity, but also the ideal channel with unlimited bandwidth actually does not exist. Therefore, the use of QPPM modulation system in engineering not only failed to improve the power efficiency advantages, but rather than the current generally adopted the best system is also slightly less. Perhaps this is why the QPPM modulation system can not be used in communications, satellite communications and telemetry at home and abroad.