Magnus Danielson wrote: > J.D. Bakker skrev: > >>> Maybe I lost track and missed something, but I don't think I ever saw >>> more on the subject of specific high-end sound cards that might be >>> useful for nutty measurements. >>> >> From an earlier list message: >> >> >>> [F]or best noise/jitter-performance an external ADC should be used, >>> connected through a digital link to a PC sound card. One could do a >>> lot worse than the TI PCM4222 eval board >>> (http://focus.ti.com/docs/prod/folders/print/pcm4222.html), which >>> accepts an external clock if so desired. At $149 (plus a tenner or >>> two for the sound card) this will likely be much cheaper than an >>> equivalent FireWire-device. >>> >> The digital link in question is S/PDIF; with the current popularity >> of Home Theater systems cheap cards with digital I/O have become >> quite prevalent. As an added bonus, S/PDIF can be run over both >> coaxial and optical media, the latter being attractive in further >> isolating PC noise from any measurement setup. And of course, a >> manufacturer's evaluation board is much better documented and more >> suited to measurement-specific mods than a random sound card. >> > > The optical link commonly being used for S/P-DIF is TosLink and it seems > like it can be the cause of many problems. It seems like some care in > doing the optical link setup is needed. I have never digged into why the > optical links have that problem. I can only guess, but bad optical > coupling seems reasonable. The multimode "fiber" seems to be leaving one > or two things to ask for. > > Cheers, > Magnus > > Hej Magnus
Relatively high jitter being one problem. Limited sampling rate being another. If one has a cheap 16 bit sound card what will it do with 24 bit data from an external ADC? Bruce _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
