Using Tina-Ti Fourier Series analysis

Hello

I have Tina-Ti, with all types of analog circuits simulations, wen I use the Fourier Series analysis it give wrong values since it give mostly between 7% and 50% of distortions reading, I did compared those distortions numbers of my circuits by making prototypes using my HP distortion analyser and the number are a allways under .01% of distortion with my HP.

I include an image of test circuit on Tina-Ti.

Do I made any errors in my use of the Fourier Series ?

A helps are welcome.

Thank you

Bye

Gaetan

At audio frequencies, assuming you change C1 to a much larger value, the distortion goes way down, 0.0025xxxxxx%.

What is your objective?

Hello

That circuit was a test for a treble booster.

Thank

Bye

Gaetan

If your signal of interest is treble frequencies and above, you could have used a high pass filter like the one in the attached file.