On 04/03/2011 2:46 PM, Jeffrey L. wrote:
sample rate of something like 25.334 MHz. I repeated the experiment
using 8 bit samples and the number improve to a more respectable 32
MHz. This seems to suggest that interleaving is still being done; the
o-scope display suggests that half of the data stream from the USRP is
still discarded (very possibly from buffer overflows?). Why am I
getting these results? Does disabling the NCO remove I/Q interleaving
and provide only real values over USB to the host?
If anyone could answer I would greatly appreciate it; I am trying to
get the highest sample rate possible from the USRP into a PC for
capturing some very short (nanosecond scale) pulses.
9000ft view here.
The USRP1 ADC runs at 64Msps, and the highest data rate you can
reasonably push over USB using the standard USRP “framing” is about
which for 8-bit samples tops out at 16Msps. If you go to 4-bit
samples, you can reasonably push 32Msps over the USB, and at 2-bit
samples, you could get to
64Msps, but it’ll require some work on the FPGA image.