I have a SB Audigy card that has a digital SPDIF output pins on the AUD_EXT header and I want to use that to connect to my speakers which have a digital coaxial jack. The cabling is a non-issue, but I will need to make a small op-amp circuit to attenuate the 0-5V TTL to -0.5V to +0.5 coaxial customary levels. I will be base my work off of the example on the following page: http://www.andrewkilpatrick.org/mind/spdif/ (scroll about half way down)
I'm just curious why do I need the combined current output from the 3 driving op-amps. My guess is that it has to do something with the 75-ohm impedance of the transmission line (coax). I'm not afraid of math, physics or electrical engineering so feel free to be as technical as you need to be in order to explain this clearly. Thanks.
I'm just curious why do I need the combined current output from the 3 driving op-amps. My guess is that it has to do something with the 75-ohm impedance of the transmission line (coax). I'm not afraid of math, physics or electrical engineering so feel free to be as technical as you need to be in order to explain this clearly. Thanks.