本振相位噪声对解调损失影响的评估方法研究

针对频率源的相位噪声随着频偏变化难以准确取值以致无法实现其对解调损失的影响进行评估的问题,提出了采用相位噪声等效面积法替代单点取值的方法。通过对相位噪声曲线分段计算面积再积分的方式计算相位噪声总功率,并以面积等效计算平均相位噪声功率。以计算的平均相位噪声功率为输入,在MATLAB中仿真PCM/BPSK调制解调过程受相位噪声的影响,并与相同条件下实际设备上的测试结果进行对比,两者在相同误码率水平下的E_(b)/N_(0)相差在0.7 dB范围内,扣除高斯白噪声下的解调损失后最大相差0.3 dB。对比试验表明,该方法可用于实际测试。

Research on evaluation of demodulation loss due to phase noise of OCXO

To acquire the optimum value of the phase noise of signal source which is changing with the deviation of frequency from the carrier, area equivalent algorithmic is proposed to replace single-point method. The average power of phase noise is calculated by area equivalent algorithmic which utilize integration of area assuming the acquisition interval as a rectangle. Simulation was carried out using the average power of phase noise as only inference in the PCM/BPSK demodulation process, and the difference between the results of experiment in the same condition and simulation is no more than 0.7dB termed as Eb/N0 in the input, which is within 0.3dB compare to the demodulation loss acquired in white Gaussian noise. Experiments results prove that it is a practical method in test.