I wonder if there is more going on than simply component spec variations.
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From the Spec Sheet for the Signal Generator mode, it says:
"Level accuracy +/- 2dB up to 800Mhz between -72dBm and -19dBm, less accuracy below -72dBm, even less accuracy below -110dBm"
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This seems to imply that perhaps something changes in the Sig Gen circuitry in the -70 dBm area (and below) that affects accuracy.
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This is right where I was seeing the degradation in the accuracy of the signal output level that I noted in my original post.
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I may try the suggestion to enter an offset to see if that works, especially for the -80 dBm area where it was off by about 3.5 dBm.
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Otherwise, I think I will use the TinySA Ultra+ attenuator down to -60 dBm, and then use external attenuators to achieve lower signal levels.? This seems like it could provide better accuracy at very low signal levels.
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Nelson
