Hello everyone.I read about this on Keysight's website,but I can't figure out the window expansion factor.If I use different window to take spectrum analysis,the ADC record size will change(window expansion factor is different for different window).I want to know how to calculate the window expansion factor.Thank you!

No real way to exactly calculate it, it is in the FW code. I'll see if I can get a table posted. This comes from the fact that each window has a different relative length (compared to no window) to achieve an equivalent BW. Due to the finite way this is done (uses integer values rather than floats, as ADC readings are integers) the normal references are slightly off and are "hand-tweaked" to make the RBW as exact as possible (can't make it exactly correct with limited ADC resolution, of course). But, you can run some examples and see what the numbers come up and infer the value from that. We might also slight tweak values at wider RBW to account for some hardware filter effects narrowing the RBW value. Tricky stuff those little bits to get everything exact. Which is why we provide you with the ADC bits (record size) directly, so there is not need to try to compute it.