bodeplot question concerning use channel 1 as reference

[hugocoolens]

I'm measuring a bodeplot for which I have set "use channel 1 as reference". I then export the data as a cvs-file and I see the dB-data in column 2 and 3 as expected. I'm wondering now whether I have to substract the dB-values in column 2 from column 3 to get the real voltage transfer characteristic of the system or are the value in column 3 already "corrected" as such?

 

regards,

hugo

[attila]

Having the "Use Channel1 as reference" checked Channel 2 (3,4) magnitude values will be relative to C1. In other words C2 will show the system transfer characteristics (magnitude/phase).
With low impedance circuit connected to Wavegen this signal, the input for the circuit might be attenuated. But connecting C1 to input and using it as reference C2(3,4) will show the actual system characteristics.
With high impedance circuit where the signal is not attenuated, C1 will be 0dB and C2 relative magnitude will be equal to real magnitude.

[hugocoolens]

Having the "Use Channel1 as reference" checked Channel 2 (3,4) magnitude values will be relative to C1. In other words C2 will show the system transfer characteristics (magnitude/phase).
With low impedance circuit connected to Wavegen this signal, the input for the circuit might be attenuated. But connecting C1 to input and using it as reference C2(3,4) will show the actual system characteristics.
With high impedance circuit where the signal is not attenuated, C1 will be 0dB and C2 relative magnitude will be equal to real magnitude.

​thanks,I thought it was like you explained here above, but just wanted to be sure 100%

kind regards,

hugo