My goal is to convert optical audio signal – Toslink – to S/PDIF coaxial input signal. The frequency is up to 96 KHz. I'm thinking about Toshiba TORX179L optical receiver. According to the datasheet, the output of TORX179L is 0,2V low, and 4V high level voltage. My question is – do I have to use some repeater like 74HCU04 here:
Or can I directly connect TORX179L to S/PDIF coaxial input? The circuit will be built inside the player.
Best Answer
The schematic shows a TORX173/176 which is confusing.
It also makes it look like the TORX modules have more than 3 pins yet these modules have only 3 pins: vdd, data and gnd, also confusing !
I believe the TORX modules already have some inverter like circuits build-in so adding inverters (the 74HCU04) seems somewhat pointless to me.
I build such a thing once, I did not include the inverters but I did include a 100 nF capacitor (using 3 x 47 nF is silly) and the resistive divider. As long as you do not have a very long Coax cable between this circuit and the SPDIF input, I expect this to work fine. Mine did anyway :-)