I have to make measurements of the RF power which a circuit is delivering, and I am using an RF spectrum analyzer for that purpose. I am a beginner in this topic, so I apologize if the question is too silly.
So, I am using a 30dB attenuator before the Spectrum Analyzer input in order to ensure that the power levels entering the instrument is well within the design limits of the device.
When I obtained the RF power spectrum, I noticed that there was a setting in the Spectrum analyzer called 'Attenuation', which I could change by using the various knobs provided in the control. When I made the measurement, the 'Attenuation' setting was on 10dB.
So, my question is, have I done a mistake by using the 10dB attenuation setting when I was actually using a 30dB attenuator externally? Or does the attenuation setting mean that an additional 10dB of attenuation is provided inside the spectrum analyzer?
To sum it up: So, using my current setup, with a 30dB external attenuator and a 10dB 'Attenuation' setting in the oscilloscope, if I read a power level of 'x' at a frequency of interest, what is the actual absolute power which is being measured? Is it x+20dB? Or x+40dB?
Also, can you please explain what the attenuation setting in a Spectrum Analyzer does?