For starters, you almost certainly cannot write to your hard drive at 15Msps. You might not even be able to reliably read that fast without underruns.
Reduce the sample rate until things start working. Disable or simplify parts of your flowgraph to see what's causing your problems. Isolate each problem and understand it before moving on. Start simple and validate each part instead of building something complex to start with. Nick On Wed, May 23, 2018, 8:02 AM Yeo Jin Kuang Alvin (IA) <[email protected]> wrote: > Hi all, > > > > Btw in this flowgraph, I’ve noticed there is nothing transmitting out when > I change the file source from repeat to no repeat. Originally, I thought > the waveform stored in file sink is immediately transmitted out from file > source and continue the process till I stop the flowgraph. > > > > When I on the repeat, signal starts transmitting out. Why is this so? > > > > Thank you in advanced! > > > > *From:* Kevin McQuiggin [mailto:[email protected]] > *Sent:* Wednesday, 23 May 2018 11:35 AM > > > *To:* Yeo Jin Kuang Alvin (IA) > *Cc:* [email protected] > *Subject:* Re: [Discuss-gnuradio] Underflow and Overflow > > > > Hi Alvin: > > > > > > > > On May 22, 2018, at 6:38 PM, Yeo Jin Kuang Alvin (IA) <[email protected]> > wrote: > > I want to do a transceiver, so instead of receiving a signal elsewhere out > of the board. I self-generate out a chirp signal internally in USRP B210 > and do a loopback to the receive port and then re-transmit out using > another transmit port. > > > > You will have to be very careful with this. Looping back the USRP output > port back to the input port can blow the front end of the USRP receiver. > Make sure that you use an external attenuator, not just a loopback cable. > I would start with 30 dB. > > > > Please tell the group more about your “transceiver": this is a broad > statement, what are you trying to achieve? There are several different > types of transceivers and the implementation will depend upon the > application you have in mind. > > > > Kevin > > > > > > > > Thank you in advanced! > > > > *From:* Kevin McQuiggin [mailto:[email protected] <[email protected]>] > *Sent:* Wednesday, 23 May 2018 9:03 AM > *To:* Yeo Jin Kuang Alvin (IA) > *Cc:* [email protected] > *Subject:* Re: [Discuss-gnuradio] Underflow and Overflow > > > > Hi Alvin: > > > > Well, for one thing, you are trying to write USRP output samples to a file > at 30 MB per second. That is likely to generate overflows. > > > > Your flowgraph indicates to me that you haven’t fully internalized how > gnuradio works and how it interacts with whatever front-end hardware you > are using. > > > > Don’t take this comment as overly critical, we all (myself included) > started with only basic understanding, and had to build our skills from > there. > > > > I suggest going to the gnuradio web site and following, as a start, the > set of tutorials that have already been recommended by others on the list. > They will help you as you start to climb the learning curve! > > > > Kevin > > Sent from my iPhone > > > On May 22, 2018, at 17:48, Yeo Jin Kuang Alvin (IA) <[email protected]> > wrote: > > Does anyone know this? > > > > *From:* Discuss-gnuradio [ > mailto:[email protected] > <[email protected]>] *On Behalf Of *Yeo > Jin Kuang Alvin (IA) > *Sent:* Tuesday, 22 May 2018 5:42 PM > *To:* [email protected] > *Subject:* [Discuss-gnuradio] Underflow and Overflow > > > > Hi all, > > > > May I know what causes my flowgraph to have so many U’s and O’s, is there > any block that causes this? I am trying to hit a higher sampling rate > possibly 20 MHz or higher. I have searched online and some suggest switching > to a different OS and I did switch from windows to Ubuntu, only a slight > difference. Some say is the computer’s processing speed not fast enough, > thus, changing a better one will help. Others did mentioned that the > flowgraph connection might cause this problem. > > > > I am getting “OOOUOO” when transmit a sine wave sampling at 20 MHz and > receive to a file sink. > > > > I am using USRP B210, running on a Intel Core i7-4700MQ CPU @ 2.40 GHz x > 8, 64 bit computer. > > > > Any help would be appreciated! > > > > <image001.png> > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio >
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