基于线性扫频的频率搅拌混响室搅拌参数选取

Stirring parameters selection for frequency-stirred reverberation chamber base on linear sweep mode

针对混响室线性扫频频率搅拌方式下的扫频间隔与搅拌带宽选取问题,在分析扫频搅拌混响原理的基础上,根据混响室测试常用的"过采样"原则与独立样本数的计算公式,给出了扫频间隔选取的上限值;并从测试精度的角度出发,利用电场均值置信区间与独立样本数之间的关系,得出搅拌带宽下限值附近独立样本数的最低要求.在某大型混响室内,通过对200MHz、500MHz及1GHz起始频率下的测试数据进行处理,验证了选取方法的合理性,并得出随频率升高,搅拌间隔与搅拌带宽的选取减小,非零带宽对测试结果的影响降低等结论.

In order to investigate the selection criteria of sweep interval and stirring bandwidth in a linear-sweep frequency stirring reverberation chamber,the stirring principle of linear-sweep mode is analyzed.Based on the over sampling principles in reverberation chamber(RC)test,the upper limit of sweep interval is determined by calculating the number of independent samples in a given bandwidth.Besides,the lower limit number of independent samples in a stirring bandwidth is given by considering the relationship with confidence interval of average field.In a large dimension RC,the S21parameters are measured at 200MHz,500MHz and 1GHz.By dealing with the data,the appropriate sweep interval and stirring bandwidth are given.Finally,the data in different stirring bandwidth are averaged,and the compared results show that the selection method is reasonable.Additionally,it is also proved that with the frequency increasing,the sweep interval and optimal stirring bandwidth is reduced.