Analysis of the Influence of Low Noise Amplifier Position on Small Signal Results

In EMC testing, it was found that changing the installation position of low noise amplifier would make a difference in the test results. The influence of the noise factor on the SNR of the system is demonstrated, and the reasons for the influence of the low noise amplifier installed in different positions are analyzed. The correctness of the analysis is verified by the method of the test, and the basic rules of low noise amplifier when testing small signal are summarized. This paper can guide engineers to apply low noise amplification correctly, and avoid the unsatisfactory measurement results due to the unusable position.