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针对直接吸收氧气光谱信号噪声较大的问题,开展了光谱信号降噪研究。以气流质量流量测量为例,说明氧气光谱信号的SNR(信噪比)要求较高。在光谱信号的测量过程当中,信号受到信号发生器等多个环节的干扰。经过对信号发生器噪声等信号进行分析,排除了“正弦噪声”的上述来源。采用自平衡检测方法,去除了该“正弦噪声”。通过对降噪后信号进行氧气浓度计算,其结果精度优于1%,证明了该方法的适用性。利用上述研究成果拓展了微小氧气光谱信号的检测能力,其光谱吸光度在10-3量级。
Aiming at the problem of large noise of direct absorption oxygen spectrum signal, the research of spectral signal noise reduction is carried out. Taking the airflow mass flow measurement as an example, the SNR (signal to noise ratio) of the oxygen spectrum signal is required to be higher. In the course of the measurement of the spectral signal, the signal is disturbed by many links such as the signal generator. After the signal generator noise and other signal analysis, excluding the “sine noise” of the above sources. Self-balanced detection method to remove the “Sine Noise ”. By calculating the oxygen concentration of the signal after the noise reduction, the accuracy of the result is better than 1%, which proves the applicability of this method. The above research results have been used to extend the detection ability of micro-oxygen spectroscopy signals with the spectral absorbance of 10-3.