Ian: Thank you for your detailed response. If I stick with eight bits and increase to 50Msps, will that solve the decimation rate problem? I realize this would result in a decimation rate of two, which would not be ideal. I may decide to only grab 25MHz, not the full 30, to keep the decimation rate at four. Thank you, again. Paul B. Huter Ian Buckley <email@example.com> wrote: Paul, With (the default) 16bit complex sample format the maximum sample rate supported on USRP2 is 25Msps, simply because that is pretty much as much data as you can get over 1G Ethernet in one direction. 50Msps is supported if you use 8bit complex samples and loose some dynamic range. The decimation rate must be an integer, thus 25Msps is a decimation rate of 4 from the raw ADC converter clock of 100MHz. Also, since the receive DSP chain cascades 2 Halfband FIR filters (each with fixed decimation of 2) before a CIC filter (With arbitrary integer decimation), it is preferable to always use decimation rates that factor by 4 so that both half band filters are active which results in the flattest passband. UHD will automatically use the half band filters in preference to the CIC when possible with the specified decimation. -Ian
on 2013-10-24 01:45
on 2013-10-24 02:00
On 10/23/2013 07:44 PM, Paul B. Huter wrote: > Paul B. Huter Keep firmly in mind that your computer will need enough "grunt" to deal with the resulting torrent of samples from the USRP. Even if you're only recording them, you'll need a minimum of 100Mbyte/second sustained write speed to your disks. If you're actually *doing something* with the samples, in the mathematical sense, you'll need lots of aggregate GFLOPS to keep up.
on 2013-10-24 02:07
Thanks, Marcus. I am just saving the data into a data file for later analysis. I only plan to save about a minute of data at a time. I intend to start small, though, and work my way up to see if my computer can handle things.