On 26.02.2011 11:36, Patrick Strasser wrote: > Just putting USB Audio Class 1 on USB 2.0 would not work, because blocks > are structured different between 1.1 and 2.0.
That was my hope, but I didn't check the specs if it would be possible. > But back in 2005 USB Audio Class 2 (UAC2) was adopted, offering notably > higher sampling rates and bit depths. Apple introduced a UAC2 in Mac OSX .. > The SDR widget people sounded every possible combination for the > mentioned OSes, with lots of tricks to get the very best out of every > driver (especially Windows UAC1). They have different firmware for UAC1 > and UAC2. UAC2 with USB3 would be a good combination. With the "usb3" "uac2" keywords in Google you find some developments for a "USB Super Speed patch" in USB3 audio drivers. I think it's realistic because UAC2 is supported in Linux and USB3 is now common in modern PC. With about 5 Gbit/s it allows broadband SDR solutions, hopefully also low-cost ones. > You can set every integer sampling rate you like withing the capacity > limit, but most drivers expect the common sampling rates. The drivers > are the limiting factor. At least in Linux you can tune the drivers if you want. > And still synchronization of clocks is a big problem. Sync problems? I thought, the "audio" devices implement a fixed sampling clock and the USB transmission is buffered to achieve a continuous stream without gaps or clock variations. Only the PC audio output has a different clock, but that problem occurs with other external sources too, like the USRPs. _______________________________________________ Discuss-gnuradio mailing list [email protected] http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
