Hypex at your service
I hooked up my UcD to an oscilloscope and I see some HF sine wave at about 400 kHz. Is this normal?
The 400kHz signal observed at the output of the amplifier is a residue of the switching nature of Class D amplifiers. This is completely normal and poses no harm. For more information, please refer to our EMI application note.
https://www.diyclassd.com/FAQ-Hypex/Technical-support/I-hooked-up-my-UcD-to-an-oscilloscope-and-I-see-some-HF-sine-wave-at-about-400-kHz.-Is-this-normal