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.

Hi Jeremy,

The step jump around 20 MHz is due to differences in noise figure of separate signal paths used in the architecture’s frequency plan. This is not an uncommon artifact of spectrum analyzers when sweeping across wide frequency ranges.

That said, the measurement accuracy remains to our published specifications and we do not believe this should impact your ability to perform EMI measurements.


 

Thanks Massimiliano,

Then how can we understand the spec"Amplitude accuracy at all center frequencies"

Customer have some question about this, I don't know how to explain.

Hi Jeremy,
the specs refer to the amplitude of a input signal, with a Signal-to-Noise ratio > 40 dB.
it is not referred to the noise floor, which is the one affected by the step in EMCVu.