digital interface transformer,help

[tomat]

can i directly replace the coupling capacitor on input dac ,usually 0.1uf with digital interface transformer such from audio note?
thanks ,hope anyone can help

cheers

[tomat]

the coaxial input coupled with 0.1uf mylar capacitor to inverter ic tc74hcuo4ap ,i plan to replace that 0.1 mylar with digital interface transfrm
help please

thanks

[Cliff45]

I'll bet this capacitor is simply used for "DC Blocking" in this application, because a excessive amount of DC bias voltage could cause any noise present on the input line to false-trigger the Toshiba TC74HC04AP CMOS inverter chip. I believe that this chip is more than likely being used as a "input buffer" for the S/PDIF input circuit, but I don't have the board schematics to look at so I am just stating the most obvious use of a chip like this one in a digital input circuit.

You should take a look at the web pages on the Scientific Conversion Inc. web site for more information on the various trade-offs of designing circuits with pulse transformers as inter-device coupling isolators. There are three papers in PDF format that are exceptionally good reading on this subject!

http://www.scientificonversion.com/

The links are on the lower part of the column on the left side of the main page.....



HTH-

[tomat]

Thank very much for the info Mr Cliff