Dear Justin,

Thanks for the indication. I will look into the stuff that you mentioned and probably think of implementing the I/Q data acquisition as well!

Dear Andrew,

Thanks for the answer! It’s a bit unfortunate that I will not be able to precalculate the bin size, but the SA124B is still a great spectrum analyser!

A follow-up and probably related question regarding the start frequency and center frequency. For a sufficiently large RBW, I find it difficult to get the exact center frequency that I set through saConfigCenterSpan. Although as far as I know, it’s usually within a bin size distance away from the one I set through saConfigCenterSpan. Is this always the case that I will never be able to set it to the exact center frequency that I want?

Hi Andrew,

Thanks for the quick reply! Thanks for reminding that the window function also plays an important role in it. I’m quite new in this spectrum analyser stuff, my initial thought would be that the bin size is the same as rbw but apparently, it’s not.

It still makes sense to me that the bin size has to be smaller than the rbw in order to make sure that there will be at least one bin that captures the full amplitude of the signal (is this correct?). But it’s still not so clear to me what will be the exact relation between rbw and bin size in the case where a flat-top window is used. Could you please explain this part in more detail?

The motivation behind this question is that I would ideally like to provide the SA124B with a frequency array that I generate myself (thus a particular bin size of my preference). Since I don’t see any way to change the bin_size directly from the provided API, I hope to be able to influence this bin_size setting through the rbw setting.

Speaking of rbw limitation, the limits I found in the SA44B-User-Manual.pdf (your link) is different from the one in https://signalhound.com/sigdownloads/SA44B/SA-API-Manual.pdf
In Page 39 Appendix: RBW and VBW, the first point of the list basically says that only 0.1Hz <= rbw <= 100KHz AND rbw=250KHz are allowed.
This is not consistent with one listed on the SA44B user manual where rbw from 0.1Hz TO 250 KHz as long as the frequency span and start frequency requirement is satisfied.

Thanks!

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