I'm trying to fit slightly overmodulated CW spectra of a single line with pepper. I wanted to include ModAmp in Exp parameters but apparently, with my data (recoded as 1st harmonic) Harmonic was set to 0 and when I'm trying to fix it as 1 it wants additional strains (that I don't have) to be added. What is the problem? The only parameters I want to vary during fitting are g and lwpp. Please, help!