基于阶跃恢复二极管(steprecoverydiode,SRD)的脉冲发生器在正弦波激励下输出的脉冲序列具有显著的频域谐波非线性,可为非线性网络矢量分析仪(nonlinearvectornetworkanalyzer,NVNA)和大信号网络分析仪(1argesignalnetworkanaly—zer,LSNA)等非线性网络测量平台提供有效的谐波相位参考信号。进一步开发其互调非线性特性的应用,提出一种基于多音信号激励SRD脉冲发生器的NVNA多谐波/互调相位参考实现方案。该方案可以在原有的各次谐波频点附近提供丰富的互调谱线,为未来的“谐波+互调”非线性微波网络测量研究提供相位参考,有效地拓展NVNA对复杂调制信号的测量功能。实验表明:SRD脉冲发生器具有较强的互调非线性,在三音激励下便可获得不少于七音的可用谐波互调谱线;该方案获得的相位参考信号具有小于±0.6。的相位测量随机不确定度,完全满足NVNA的指标要求;互调谱线的分辨率可以任意设置,从几十MHz到百Hz以下。其灵活性和频率分辨率指标优于目前所有的谐波相位参考。
The step recovery diode (SRD)-based pulse generator is a classical microwave pulse-formation technique, whose the harmonic nonlinearity under sinusoidal stimulus is utilized as the phase reference of nonlinear vector network analyzer (NVNA) and (large signal network analyzer, LSNA). This paper further develops the application ofits inter-modulation nonlinearity and proposes the implementation scheme of an NVNA poly-harmonic inter-modulation phase reference based on the SRD-based pulse generator and multi-tone stimulus. Experiment results show that this method can provide rich inter-modulation components around each harmonic, which are available for NVNA to use; and under three tone stimulus, usable harmonic inter-modulation spectrum lines with not less than 7 tones can be obtained. The scheme has tne resoluhe advantages of small phase noise about + 0.6° and flexible spectrum lition that can be setup from tens of MHz to less than hundreds of Hz.