IF overload ?

[Ivan Ionov]

Hello,

I set TG44 output to -30dBm 10MHz
input reference is set to -10dBm,
Why I see IF Overload warning in this case? The signal is 20dB lower than upper limit. It appears only around 10MHz and when span is 200KHz and less. Is 10MHz area has some specific limitations in BB60c?

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[Andrew]

Ivan,

The overload could be energy in the entire acquisition band you are currently in. In your case, at 10MHz, the device is using the direct RF path which would account for frequency from 9kHz -> 27MHz. If you increase your span from 9kHz to 27MHz do you still see the overload?

Regards,
A.J.

[Ivan Ionov]

If I increase span to 500KHz or more, this warning disappears. But also I see different noise level on left and right part of the screen (>10MHz and <10MHz different RF path are used).

It looks like the span less than 200KHz tries to use only single RF path (looking at noise, imho this is >10MHz path, it has less noise), and in this case something strange happens with overload warnings.

[Ivan Ionov]

Here is a screenshot with 500KHz span. -11dBm input (much higher than on prev picture), -10dBm reference level (the same as on first screenshot), no overload.

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