Re: [LAU] USB cable with ferrite core

From: Clemens Ladisch <clemens@email-addr-hidden>
Date: Fri Dec 30 2016 - 08:12:34 EET

Ralf Mardorf wrote:
>Saw + pincers = ferrite core removed = no xruns anymore

Thank you for doing the experiment.

>>2) Unfortunately, USB is inherently noisy. Using a ferrite to reduce
>>common-mode currents in the cable is, in principle, a good idea.

Using a common-mode choke works only for differential signals.
But USB also uses common-mode signalling for certain states.
Ferrites on a USB cable should be one per data line, and sized so that
only frequencies higher than the USB signalling rate are filtered out.

I would guess that that cable was (originally) intended for low speed only.

Regards,
Clemens

_______________________________________________
Linux-audio-user mailing list
Linux-audio-user@email-addr-hidden
http://lists.linuxaudio.org/listinfo/linux-audio-user
Received on Fri Dec 30 08:15:02 2016

This archive was generated by hypermail 2.1.8 : Fri Dec 30 2016 - 08:15:02 EET