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信号源是物质介电参数测量中的核心设备之一。现代化的介电测量技术要求信号源向高精度、数字化和多功能方向发展。一种对测量结果便于进行数字化处理的相关检测在介电测量中正日益受到重视。在图1所示的一个典型例子中,使用开关型乘法器一类的鉴相电路,将通过样品的被测信号V_s与同频率、幅值为1的参考方波V_r相乘,利用V_s与V_r在时间轴上的前后相关性,给出由V_s的幅值和相位信息所决定的模拟信号。图中的信号源与普通信号源的主要区别是前者应具备移相的功能。即对所提供的正弦信号和参考方波信号在全相位范围内能灵活地改变相位。由廉
The signal source is one of the core devices in the measurement of material dielectric parameters. Modern dielectric measurement technology requires high-precision signal source, digital and multi-functional direction. A related test that facilitates the digitization of measurement results is gaining more and more attention in dielectric measurement. In a typical example shown in FIG. 1, a phase detector circuit such as a switching multiplier is used to multiply the measured signal V_s passing through the sample by a reference square wave V_r with the same frequency and a magnitude of 1, using V_s V_r on the time axis before and after the correlation, given by the V_s amplitude and phase information of the analog signal. The main difference between the signal source and the ordinary signal source in the figure is that the former should have the function of phase shifting. That is, the provided sinusoidal and reference square wave signals have the flexibility to change phase over the full phase range. By Lian