Converting Coax to AES?

Also the impedance difference will mess up the waveform.

Here is one solution, for $98, although I suspect that with a little looking you'll be able to find something less expensive (this one can handle two signals, which you don't need):

http://www.bhphotovideo.com/c/product/395533-REG/Hosa_Technology_CDL_313_CDL_313_Data_Link.html

Regards,
-- Al