kerin.liu wrote: Thank you for your reply! Can I understand that? The sound card will automatically convert TS signal into TRS signal. Suppose that if there is noise on the ground wire during the conversion, the analysis results will be affected after the conversion, right?
the input buffers expect differential signals. so the servo balanced stage will do:
Input+ = (Hot - Cold)/2 + bias
Input- = - (Hot - Cold)/2 + bias.
You need to make sure cold is connected to the ground. leaving that floating will cause noise in the conversion. The manual states that very clearly.
Also unbalanced signal is prone to have ground loop and interference, which make such signal nosier.