I've been trying for a few days to convert an experimentally obtained (frequency against magnitude and frequency against phase) graphs to a bode plot and then construct a transfer function from the bode plot
I constructed a table:
1) Converted each frequency from Herts to Rad/s by multiplying it by 2*Pi
2) Converted each magnitude to db by multiplying it by 20log(magnitude)
Note: As seen in the original graph, all the magnitudes are negative. When converting to db, you cannot take the log of a negative number so I assumed it to be positive. Am I correct? will this affect my bode plot?
I understand that my transfer function will be a first order because the phase shifts 90 degrees meaning the highest power of the denominator will be 1. in other words, there will be 1 pole in the denominator.
In summery, my questions:
1) Was I correct in converting the negative magnitude to db by ignoring the negative value? 2) What will be the final transfer function of the constructed bode plot?