Spectrum analyzer RSA306B "unstable test data" at no input signal

Hello all,

updated the question in the document below.

Just had the chance to check with customer yesterday.  the key point is why the curve will rise or drop suddenly without any input signal.  we found the curve was not come out when all the test is finish.  it seems depend on the stop frequency. the data may be acquired several times,and the rise or drop happens between the acquision.

attached please find the document for the detail.