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一、引言 远红外(FJR)激光干涉仪广泛用于等离子体电子密度测量。探测光束通过等离子体产生相移,参考光束不通过等离子体,两道信号由TGS热释电探测器分别接收,两者的相位差就是被测物理量,它与线电子密度成正比。目前,国内外此类干涉仪都用模拟或数字电路的相位计过零比较信号相位差。这种硬件相位计性能指标不稳定,制作费用昂贵。我们提出一种数值方法,通过软件计算相位差,这种方法可提高信号的时间分辨率。
I. Introduction Far-infrared (FJR) laser interferometers are widely used in plasma electron density measurement. The probe beam produces a phase shift through the plasma, the reference beam does not pass through the plasma, and the two signals are received separately by the TGS pyroelectric detector. The phase difference between the two is the measured physical quantity, which is proportional to the linear electron density. At present, such interferometers at home and abroad use analog or digital circuit phase meter zero-crossing signal phase difference comparison. This hardware phase meter performance indicators of instability, the production cost is expensive. We propose a numerical method to calculate the phase difference through software, this method can improve the time resolution of the signal.