Hello EEVblog people!
I'm trying to characterize the audio performance such as SNR, THD etc. of a filterless class-D amplifier. I have read application notes on how to do this, where you low pass filter the high frequency voltage waveforms and analyze it with an audio analyzer. I also have a simulation environment up where I can do these things with an FFT. The paradox is, that is get different results when analyzing the voltage waveform vs. the current waveform in the speaker inductor(coil). I'm not sure what is most correct here. It seems that in the literature you analyze the voltage, however isn't it the current that actually moves the speaker?
What are your thoughts on this? Is it the current in the speaker that defines the 'sound' or the differential voltage across it?
Regards
Chosee