深入研究了非理想3×3耦合器对相位解调结果的影响, 理论分析了非理想相位条件下的解调结果。仿真计算了相位偏差在±1~5°均匀分布时解调结果与原始结果的相关系数, 分析了干涉信号存在幅度噪声时对解调结果的影响。对于特定的系统, 相位偏差在解调结果中引入了一个常数系数, 相位偏差在±1~5°均匀分布时常数系数的均值分别为0.9999、0.9996、0.9991、0.9984和0.9975。干涉信号的幅度噪声会明显恶化解调算法的性能, 为保证解调信号与原始信号相关系数在0.99以上, 需要控制干涉信号的幅度噪声水平在6.4%以内。

The impact of non-ideal 3×3 coupler on phase demodulation is studied in depth, and demodulation are analyzed theoretically under non-ideal condition. The correlation between demodulation results and original signals are calculated with uniform distribution of phase deviation in ±1~5°, and the impact of amplitude noise of interference signals are analyzed. For a given system, phase deviation introduces a constant coefficient on demodulation results, phase deviation in ±1~5° correspond to constant coefficients of 0.9999, 0.9996, 0.9991, 0.9984 and 0.9975, respectively. The amplitude noise of interference signals obviously deteriorate the performance of demodulation algorithm. In order to ensure the correlation coefficient between demodulation signal and original signal is above 0.99, the amplitude noise level of interference signals needs to be controlled within 6.4%.