I would be surprised if a converter of this sort actually existed, but I figured it was worth asking. Basically, I'm looking to hook my PC up to my surround sound receiver. The only open input I have is a digital coax. On my PC, I don't have any sort of digital output besides HDMI, but my receiver wouldn't take that anyway.
What I need is some sort of adapter that can take multiple 3.5mm line-outs and convert them into digital coaxial. I'm guessing it may be rather expensive since it would have to have a decoder built-in, but I'm looking for alternatives to buying expensive sound cards.