对瞬时信号波长的相频检测

Phase-Frequency Detection for Instantaneous Signal Wavelength

首先,将短基线相差测向严格解和多普勒频移方程联解,获得基于相差测量的频移表达式;然后,利用中心频率、瞬时测频值和多普勒频移间的关系,将频移表示式化为一个仅包含未知信号波长的一元三次函数方程,从中可导出基于瞬时测频和相差测量的信号波长解析公式。在此基础上,还通过模拟比较,采用合并等值项的方法对解析公式进行了简化。对简化解的误差分析表明,对于分米波信号,且在瞬时测频的测量误差大于数兆赫的情况下,由基于短基线相差测量所得到的波长测量误差可小于1mm。所提出的新方法可能是至今为止最具有工程应用价值的。

After using the combined solution between the strict solution of phase difference DF based on short-baseline and Doppler shift equation, an expression of Doppler shift is obtained. Then according to the relationship between centre frequency, instantaneous frequency measurement and Doppler shift, a simple cubic equation which only contains an unknown signal wavelength is given and the analysis formula of signal wavelength is derived by measuring for instantaneous frequency and phase difference. The analysis formula is predigested by comparing and combining equivalent item. The error analysis for reduced form equation shows that the wavelength measurement error obtained by new method based on short-baseline phase difference measurement may be less than 1 mm when the measurement error for measured frequency is larger than several megacycles for decimeter wave signal. This may be the best method which can apply to engineering design up to the present.