Hi, I while ago we bought two USRP2. When they came we tested them with the usrp2_siggen and usrp2_fft programs. Also we had two USRP1 and used USRP_oscope to see the waveforms produced by USRP2. Everything seemed to work OK. Then we didn't do anything with the USRP2 for a while. I few days ago I tried using them again and discovered I couldn't transmit or receive anything. I saw in the mailing list that those who got an SD-Card labeled "9/22/08" must update their firmware so I updated the firmware using the images from the site. Now I can receive(?) but I can't transmit. I mean no signal is transmited from the USRP2'santenna because if it where I would see it in usrp_oscope. Samples however are send from the PC to USRP2 because the leds on the Ethernet port light when I run a program like usrp2_siggen or something of my own. Does anyone has any idea about what's wrong? How do I check if the transmit frequency has been set OK? In another message it was mentioned that there is no PGA on USRP2. Then what does set_gain() in a usrp2 sink or source? I also noticed something about the received signal. First the noise variance seems to change when there is a signal and when there is not. Is this normal? Is there some AGC circuit that causes this? If so can I disable it from code. I haven't noticed anything similar in USRP1. Thank you Manolis
on 2008-11-03 13:18
on 2008-11-03 17:09
On Mon, Nov 3, 2008 at 4:03 AM, Matigakis Emmanouil <firstname.lastname@example.org> wrote: > ...so I updated the firmware using the images from the site. There is a new firmware image as of this morning, please update to that. Also, did you update the FPGA code? If not, you'll need to do so. > In another message it was mentioned that there is no PGA on USRP2. > Then what does set_gain() in a usrp2 sink or source? These two functions set the gain on actual daughterboard, if it has a gain control. -Johnathan
on 2008-11-03 18:47
>There is a new firmware image as of this morning, please update to >that. Also, did you update the FPGA code? If not, you'll need to do >so. I did update the FPGA bitstream. I am wondering if it could be a hardware problem. It seems to me that neither of the two USRP2 we have amplify the signal that is received of transmited. I don't really believe that it's probable that two devices malfunction at the same time. That is why I got confused with the set_gain() methods. Has anyone encountered a similar problem when using the USRP2? Thank you for your help Manolis
on 2008-11-14 16:15
Today I updated gnuradio to current svn9988. And while doing that I also downloaded the binary package of mb-gcc and built the firmware- files, successfully thanks to the wiki and a well known search- engine. The new firmware was loaded onto the sd- card successfully(?) is there supposed to be some output from u2_flash_tool, I can't locate the source for it, so I can't check for myself. But since I could run find_usrps with the (probably) new firmware, I guess it went fine. I then tried all the test- programs, and they ran fine (find_usrps, tx_sample, ... from usrp2/host/apps/), before lunch, but when I got back from lunch they didn't. I simply can't transmit according to my hardware oscilloscope. Although I see packages flowing on my eth0- device (using wireshark). And when I try rx_streaming_samples (with a signal- generator as source, generating a 100kHz sine) I suddenly receive a lot of noise. Looking at the fft of the received signal one could say that it _might_ be a sinusoid in there, but very weak. But only after lunch, before lunch the received signal was a noise free sinus of 100kHz... The only thing that is working as expected after I got back is find_usrps. I think I'll never eat lunch again ;) I'm out of ideas of how to solve this. Suggestions of things to try and/or check for, no matter how simple would be appreciated. BR //Mattias Kjellsson
on 2008-11-14 17:00
On Fri, Nov 14, 2008 at 7:14 AM, Mattias Kjellsson <email@example.com> wrote: > Today I updated gnuradio to current svn9988. And while doing that I also > downloaded the binary package of mb-gcc and built the firmware- files, > successfully thanks to the wiki and a well known search- engine. You will also need to either build or download the FPGA firmware. > The new firmware was loaded onto the sd- card successfully(?) is there > supposed to be some output from u2_flash_tool, I can't locate the source for > it, so I can't check for myself. There is no output upon success. You can re-run the same command, but use -v instead of -w to verify the SD card contents match the file you copied into it. -Johnathan
on 2008-11-15 15:06
Hi Kjellsson, we had the same problem a while ago and we still haven't been able to fix it. It seems that USRP2 receives but doesn't amplify the signal so it is very weak compared to the noise. We also can't transmit from the USRP2 at all just like you. Have you been able to do something yet? Manolis.
on 2008-11-17 23:21
It looks like you are both using the wrong software. For transmitting, use usrp2_siggen.py and for receiving use usrp2_fft.py.