无源互调测试系统接触点的误差评定

Error evaluation for contact points of passive inter-modulation measurement system

随着通信系统快速发展,对无源器件互调值精确度的要求不断提高,无源互调测试系统中原本被忽略的接触点的相互影响造成被测器件互调值偏差这一问题变的日益重要。针对该问题,把接触点的相互影响简化为多个连接器相连(接触)的模式,根据多连接器相连接的数学模型,建立起了无源互调系统接触点导致的误差分析模型。采用工作在900 MHz频段的2台互调仪,分别对8个被测件,每增加1个DIN7/16的连接器做20次测试,直到连接器增加至7个。测试结果表明,由于连接器的接触点的影响将导致被测件互调指标测试结果远远超过标称值,采用所建立的误差分析模型进行修正,可以使被测件的互调指标控制在无源器件所要求的精度内。

With the rapid development of communication system, the requirement for the accuracy of passive intermodulation values is increasing. The interaction between contact points causes the deviation of PIM of the device under test; the problem that was neglected becomes increasingly important. Aiming at this problem, this paper simpli- fies the interaction among contact points as a model of multi-connectors connected （contacted） each other. Based on the mathematical model of connected multi-connectors, we have established an error analysis model of contact points in passive inter-modulation test system. We use two inter-modulation analyzers working in 900 MHz band and meas- ure eight pieces of DUTs. Each time when one DINT/16 connector is connected 20 tests are carried out until the number of connectors reaches to seven. Test results show that due to the impact of the connector contacts, the inter- modulation test result of DUTs is far beyond the norminal value. Using the proposed model of error correction, the PIM of DUTs can be controlled within the required accuracy range of the passive components.