OT - VAC resampling, killing I/Q phase relationship?
Posted: Wed Apr 25, 2018 5:42 pm
OT, but not sure where else to ask:
I have an audio-rate I/Q test "sink" that I use when working with "sound card sampling" I/Q stream sources.
I thought it would be useful to set up VAC, so that I could use multiple "sink" (input/receiving) programs at the same time for comparison.
I've tried both Eugene's VAC and VB cables with the same results. Everything is running at 96K both in and out, so no resampling is explicitly required, except perhaps for clock-matching.
The problem I'm having with this is that when I look at the spectra from a 96K I/Q stream that's come across the VAC cable, I see it's been band-limited to 48K and the I/Q relationship has been spoiled. Again, I have both source and sink set to sample at 96K, and am using 16-bit signed samples on both ends as well. I've looked at available options for the VB cables at least and haven't seen anything relevant beyond setting the "internal" rate to 96K, which I did.
Any ideas? I'm hoping it's something I'm doing, I'd like to have all my test apps running in parallel.
Thanks,
Jim N7CXI
I have an audio-rate I/Q test "sink" that I use when working with "sound card sampling" I/Q stream sources.
I thought it would be useful to set up VAC, so that I could use multiple "sink" (input/receiving) programs at the same time for comparison.
I've tried both Eugene's VAC and VB cables with the same results. Everything is running at 96K both in and out, so no resampling is explicitly required, except perhaps for clock-matching.
The problem I'm having with this is that when I look at the spectra from a 96K I/Q stream that's come across the VAC cable, I see it's been band-limited to 48K and the I/Q relationship has been spoiled. Again, I have both source and sink set to sample at 96K, and am using 16-bit signed samples on both ends as well. I've looked at available options for the VB cables at least and haven't seen anything relevant beyond setting the "internal" rate to 96K, which I did.
Any ideas? I'm hoping it's something I'm doing, I'd like to have all my test apps running in parallel.
Thanks,
Jim N7CXI