Pocket DI is small passive based Direct injection box. It’s used for mainly matching impedance between electronic musical instruments and mixer.
But this box have been designed as to separate the grand between PC and USB based musical instruments.
When you have trouble about digital noise comeing from PC that connected by USB, you can reduce it using this box for the output of your musical gear.

This DI box don’t need extra power source that called phantom from mixer. You can use it for your simple mixers.

In the case of Pocket miku that’s released from Gakken last month, you can reduce it’s noise almost over 30db. I think that you can’t hear the noise coming from PC when you operate another stuff in DTM. it may keep your concentration high! Get clear sound from your gadget.
next figure shows noise and sound rate. red line shows miku voice and green line shows no sound. “Before” shows “direct connecting”. “After” shows less noise than before using Pocket DI.