Can I do that through GNU Radio, or is that a configuration I need to make through the USRP (ie Do I need to run the setup for the USRP)?
Paul B. Huter On Nov 23, 2013 10:07 AM, "Tom Rondeau" <t...@trondeau.com> wrote: > On Sat, Nov 23, 2013 at 11:02 AM, Paul B. Huter <paul.b.hu...@gmail.com> > wrote: > > Thanks, Tom. Just to clarify, the 1Msps comes from the sample rate of 50M > > and the decimation of 50, correct? Also, is this going to record 10 > seconds > > of "real-time" data? I was having issues with real-time, due to the large > > data stream, so will this record data from t=0 to t=10, just not in > > real-time? > > > > Paul B. Huter > > If you're not running in real time, then you're dropping samples. The > way these devices work is that they drop packets of samples, which can > be quite a lot of data. So you'll store in your file sink 10 seconds > worth of data, but if you're dropping samples, it won't be 10 > consecutive seconds of data. > > But I just realized something. We've been trying to help you out > constructing your filters and everything, but why are you setting your > input sample rate to 50 MHz only to down-convert in software? The USRP > will do that for you! You can ask the USRP to set the channel and > sampling rate to what you want, then you just take that input and > capture it. It's done it all for you! And since you're talking about > just taking samples for a small amount of time, it's not like you're > trying to use this concept to quickly change channels instantaneously. > So why not let the hardware do the work for you? > > Tom > > > > > On Nov 23, 2013 9:54 AM, "Tom Rondeau" <t...@trondeau.com> wrote: > >> > >> On Sat, Nov 23, 2013 at 10:44 AM, Paul B. Huter <paul.b.hu...@gmail.com > > > >> wrote: > >> > I ran my "record" setup for over 10 seconds, but when I run the data > >> > file > >> > back through my "playback" I only get about two seconds (if that) of > >> > result. > >> > What happened to all the data, and how can I change things next time > to > >> > get > >> > all the data? > >> > > >> > My record setup is as follows: > >> > > >> > Rate: 50M > >> > USRP Source > >> > Low Pass Filter > >> > Decimation: 50 > >> > Cutoff Freq: 15M > >> > Transition Width: 5M > >> > File Sink > >> > > >> > Paul B. Huter > >> > >> > >> Try this. You only want to capture for a certain length of time, which > >> means a certain number of samples. So put a gr::blocks::head block > >> between the filter and file sink. The number of items you'll want is > >> going to be samp_rate (samps/sec) * time (secs) (and we know samp_rate > >> here is 1 Msps). That will store exactly that many samples and then > >> shut down the application. > >> > >> Tom >
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