调制频率抖动对相干检测的影响及消除算法

介绍了调制频率偏移抖动的起因,并分析了相干检测过程中由于调制频率偏移抖动所引起的误差,对模拟和数字相干调制和解调过程建立了数学模型。基于文中所建立的数学模型,确定了调制频率偏移抖动对模拟和数字相干调制和解调过程的影响,特别是其对离散采样过程的影响关系。最后,提出了一种基于模糊逻辑的隶属函数加权采样算法,并进行了实验。实验结果表明,使用隶属函数加权采样算法后,当调制频率偏移范围小于±9.2%时,相干检测的精度未受影响;而未使用隶属函数加权采样算法时,当调制频率偏移范围大于±3%时,相干检测的精度便会受到影响。结果还表明,调制频率偏移抖动对模拟和数字相干检测过程影响的数学模型在相干检测应用领域很有价值,提出的隶属函数加权采样算法能够有效地消除调制频率偏移对相干检测的影响,其效果已经在应用中得到了验证。

Effect of modulation frequency Jitter on coherent detection and its elimination algorithm

The causation of MFJE (Modulation Frequency Jitter and Excursion) is generally introduced,and the error of MFJE in coherent detection is analyzed at the same time, the mathematic models of MFJE error in analog and digital coherent detection process are built. Based on the mathematic models, the effects of MFJE on analog and digital coherent modulation-demodulation process are identified, especially the effect of MFJE on discrete sampling. Finally, a Membership Weighted Function Sampling ( MWFS ) algorithm is proposed. The experimental result shows that the precision of coherent detection has not been affected in a modulation frequency excursion range of ±9.2% with MWFS , compared with the range of ±3% without MWFS . The result also shows that the mathematic models of MFJE error in analog and digital coherent detection process are valuable in coherent detection application field and MWFS proposed in the paper can eliminate the effect of modulation frequency excursion on coherent detection efficiently, which has been certified in practice.