Oscilloscope for PC

I need advice on choosing an accessory for a PC, which I would replace a large oscilloscope for space reasons. The difference between analog and digi is clear, area of ​​use as well. But it makes sense to solve the oscilloscope with an additional device to the PC, when the PC produces quite a lot of interference?

If you have experience, please advise me. Does the BITSCOPE project tell you something??

Thanks to Franta OK2VFS fstepan@spsefren.cz