Re: [Discuss-gnuradio] Capture and plot 802.11 frames (Stratos Keranidis)
Hello Stratos, For capturing 802.11 frames you can take a look here: https://www.cgran.org/wiki/SPAN80211b Unfortunately, that is just for the 802.11b standard. On the other hand, there is one encoder developed for the 802.11g standard, here: https://www.cgran.org/wiki/ftw80211ofdmtx I the last case, I was able to generate 802.11g frames with an USRP2 and detect them with the wifi card in my laptop. That is not what you want but can be a good starting point. Also, I would suggest to take a look to Wireshark (http://www.wireshark.org/) if you want/need to understand all the stuff related with sniffing (i.e, capturing data generated by other equipment). Hope it helps, Mario El 06/10/2011 18:01, discuss-gnuradio-requ...@gnu.org escribió: Re: Capture and plot 802.11 frames (Stratos Keranidis) ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Phase demodulation
Achilleas Anastasopoulos wrote: arctan (imag(out)/real(out)) plus some filtering to remove out of band noise (it would be nice also to make sure you avoid discontinuities inherent in the arctan function)... I would like to add that you should use four quadrant arctan, i.e. add or subtract pi to the above if the real part is negative. Regards /Mikael Olofsson Universitetslektor (Associate Professor) Linköpings universitet --- E-Mail: mik...@isy.liu.se WWW: http://www.commsys.isy.liu.se/en/staff/mikael Phone: +46 - (0)13 - 28 1343 Telefax: +46 - (0)13 - 13 9282 Office: Building B, top floor, corridor A, between entrances 27-29. --- ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] FM Capture
Am 2011-10-06 12:55, schrieb JOSE FELIX HERNANDEZ BARRIO: do you know of any radio capture file of the fm band on internet ? could anyone with access to the required hardware make a capture an upload it to internet? Have a look at the Wiki and the mailing list archive (hint: Google). There used to be great captures by late Michael Gray, KD7LMO, but these seem to be lost. Anyway there are some samples arround, and if you ask on the list for freshly recorded sample I think you will get some. Does it have to be something special like overlaping stations or big sampling rate/band width? You know, these can get big, like one minute of 16bit/S 512KSps is like 480MiB. Regards Patrick -- Engineers motto: cheap, good, fast: choose any two Patrick Strasser patrick dot strasser at student tugraz dot at Student of Telemat_cs_, Graz University of Technology, Austria ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Remote Access to USRP testbed with GNU Radio
I believe people are answering the question but are slightly off target. Create a group on your Linux distribution call USRP, make sure those users you want control the USRP as users (AND NOT ROOT) are in this group. The go read the gnuradio wiki about the other changes granting device permissions etc. This is how remote users gain control of the USRP locally without sudo as well as over SSH whether the machine is accessible over a LAN only or the full internet. Bob On Oct 6, 2011 7:15 PM, Ian Buckley ian.buck...@gmail.com wrote: Remember that you in fact are not required to Login to the USRP at all, it isn't an interactive device, more like a peripheral device to a host computer. Thus your remote access limitation is purely dependent on the remote host you utilize to run GNURadio to interface to the USRP. The main issue you are like to run into is using update intensive GRC graphical tools such as FFT via X or VNC which can be very problematic over WANs. In terms of the USRP itself, if the location is truly remote with no local support then it would be wise to utilize A USRP other than the USRP2 since this model requires the SDCard to be physically replaced to upgrade firmware+FPGA. It would also be wise to have a remote accessible PDU so you can power cycle the USRP if necessary. I've built austere lights out remote satellite ground stations that use USRP's with great success. -Ian On Oct 6, 2011, at 3:31 PM, Kunal Kandekar wrote: I have accessed and used a USRP over SSH before. In fact, I accessed it over the Internet, not just a LAN. Although I was not the one who set it up, as far as I know, nothing additional had to be done to enable this. I simply logged in as the user account under which GNU Radio had been installed. The machine was running Ubuntu, in case it matters. Kunal On Thu, Oct 6, 2011 at 6:04 PM, Guanbo Zheng gbzh...@gmail.com wrote: Hi, all We are interesting to build up a USRP testbed which allowed the guest remote access to do some experiments. I have seen someone's youtube video that they control the USRPs to transmit different signals through SSH access. But I want to double check if it allowed guest control of USRP devices ? Are there any other settings I need to take care of, in order to implement this? Thanks a lot for any suggestions! -- Regards, Guanbo ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Want to help? Here's something....
On 10/03/2011 11:32 AM, Tom Rondeau wrote: Hello everyone, Here's a general call for help on the GNU Radio project if you are so inclined. If you've wanted to contribute back to the code, but weren't sure how to make a difference, there are lots of little things to look at. We've set up a Jenkins continuous integration server that keeps track of the code issues, including enumerating all TODO and FIXME comments through the source code. It also tests and graphs the test code we've put in there. You can see these results here: http://www.gnuradio.org/jenkins/job/GNURadio-master/ How often does this update? Philip ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Remote Access to USRP testbed with GNU Radio
http://gnuradio.org/redmine/projects/gnuradio/wiki/UbuntuInstall has configuring USRP support. Following these instructions will allow users in the USRP group to run the hardware without root access. Bob On Fri, Oct 7, 2011 at 7:01 AM, Robert McGwier rwmcgw...@gmail.com wrote: I believe people are answering the question but are slightly off target. Create a group on your Linux distribution call USRP, make sure those users you want control the USRP as users (AND NOT ROOT) are in this group. The go read the gnuradio wiki about the other changes granting device permissions etc. This is how remote users gain control of the USRP locally without sudo as well as over SSH whether the machine is accessible over a LAN only or the full internet. Bob On Oct 6, 2011 7:15 PM, Ian Buckley ian.buck...@gmail.com wrote: Remember that you in fact are not required to Login to the USRP at all, it isn't an interactive device, more like a peripheral device to a host computer. Thus your remote access limitation is purely dependent on the remote host you utilize to run GNURadio to interface to the USRP. The main issue you are like to run into is using update intensive GRC graphical tools such as FFT via X or VNC which can be very problematic over WANs. In terms of the USRP itself, if the location is truly remote with no local support then it would be wise to utilize A USRP other than the USRP2 since this model requires the SDCard to be physically replaced to upgrade firmware+FPGA. It would also be wise to have a remote accessible PDU so you can power cycle the USRP if necessary. I've built austere lights out remote satellite ground stations that use USRP's with great success. -Ian On Oct 6, 2011, at 3:31 PM, Kunal Kandekar wrote: I have accessed and used a USRP over SSH before. In fact, I accessed it over the Internet, not just a LAN. Although I was not the one who set it up, as far as I know, nothing additional had to be done to enable this. I simply logged in as the user account under which GNU Radio had been installed. The machine was running Ubuntu, in case it matters. Kunal On Thu, Oct 6, 2011 at 6:04 PM, Guanbo Zheng gbzh...@gmail.com wrote: Hi, all We are interesting to build up a USRP testbed which allowed the guest remote access to do some experiments. I have seen someone's youtube video that they control the USRPs to transmit different signals through SSH access. But I want to double check if it allowed guest control of USRP devices ? Are there any other settings I need to take care of, in order to implement this? Thanks a lot for any suggestions! -- Regards, Guanbo ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio -- Bob McGwier ARS: N4HY ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Remote Access to USRP testbed with GNU Radio
On 07/10/2011 8:53 AM, Robert McGwier wrote: http://gnuradio.org/redmine/projects/gnuradio/wiki/UbuntuInstall has configuring USRP support. Following these instructions will allow users in the USRP group to run the hardware without root access. Bob Also, the build-gnuradio script takes care of this for the calling user (but not any others). I want to add that as a possible feature--perhaps prompt for the userids you wish to be added or something. Or maybe have it add all the ordinary users. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Want to help? Here's something....
On Fri, Oct 7, 2011 at 7:40 AM, Philip Balister phi...@balister.org wrote: On 10/03/2011 11:32 AM, Tom Rondeau wrote: Hello everyone, Here's a general call for help on the GNU Radio project if you are so inclined. If you've wanted to contribute back to the code, but weren't sure how to make a difference, there are lots of little things to look at. We've set up a Jenkins continuous integration server that keeps track of the code issues, including enumerating all TODO and FIXME comments through the source code. It also tests and graphs the test code we've put in there. You can see these results here: http://www.gnuradio.org/**jenkins/job/GNURadio-master/http://www.gnuradio.org/jenkins/job/GNURadio-master/ How often does this update? Philip Right now, it's once a week. Early Monday morning for the master branch and early Tuesday morning for the next branch. If this becomes a really useful tool that people are using constantly, I could be easily persuaded to go to nightly builds. At that point, though, we'll want to launch a new machine to handle the compilations and not over-burden our web server. Tom ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Cheap portable antenna for SSB + CW w/ USRP1?
Thanks Marcus, I realize I'm asking for the impossible at a certain level—adequate but not stellar should be fine :) Glad to know that the roll-off is not so steep as to make 30MHz / 50MHz unusable as well… Btw, I finally managed to get UDP between my external app and GnuRadio up running—thanks again for all the help! Cheers, Mark -- mark.cetilia.org | mem1.com | reduxproject.com On Oct 7, 2011, at 12:03 AM, Marcus D. Leech wrote: On 06/10/11 11:51 PM, Mark Cetilia wrote: Hi all, Just curious if anyone might have some suggestions for a cheap (ideally $100) portable antenna for receiving (not transmitting) SSB + CW? Something that can easily fit into a carryon bag, can be used indoors and set up / broken down quickly would be great. It would be nice to cover as much of the LFRX's range as possible—160 to 6 meters I guess? The Ettus site mentions DC to 30 MHz, but the board has DC to 50 MHz silkscreened onto it—not sure which is correct? The LFRX has a not-very-steep roll-off above 30MHz, so it's usable above 30MHz. I've got my eye on an MFJ-1622 right now, which supposedly covers 40 to 2 meters. Not completely optimal, but it's looking decent for the price + form factor… Anybody out there have experience with that antenna? Other possible leads would be greatly appreciated as well. Thanks so much! The MFJ-1622 is probably adequate, but not stellar. Its hard to make an antenna that is both a good match, *and* a good radiator over wide frequency radiators, *and* is physically compact. -- Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Phase demodulation
Just to make a note on the more theoretical aspect of this problem:
If you want to avoid all complications arising from the discontinuous
arctan, you can (and technically/theoretically you should)
work with the actual incoming signal r(t)=exp(j theta(t)) + n(t)
and its hypothesized estimate s_hat(t) = exp(j theta_hat(t)),
and minimize their Euclidean distance (over a horizon T) under the
constraints (bandwidth) of your signal theta_hat(t).
What this boils down to is:
find theta_hat(t) satisfying the BW constraints that maximizes
the quantity sum_{t=1}^T |r(t)| cos[arg(r(t))-theta_hat(t)].
BTW, the fine point above is that you cannot set theta_hat(t)=arg(r(t)),
because this assignment does NOT satisfy the BW constraints of your
initial signal theta(t) or theta_hat(t).
This maximization problem is solved APPROXIMATELY using a PLL which is
implemented in gnuradio in various forms.
Also the algorithms suggested earlier (evaluate arctan() and smooth it)
can be thought of as approximate solutions of the above problem.
Achilleas
On 10/7/2011 5:40 AM, Mikael Olofsson wrote:
Achilleas Anastasopoulos wrote:
arctan (imag(out)/real(out)) plus some filtering to remove out of band
noise (it would be nice also to make sure you avoid discontinuities
inherent in the arctan function)...
I would like to add that you should use four quadrant arctan, i.e. add
or subtract pi to the above if the real part is negative.
Regards
/Mikael Olofsson
Universitetslektor (Associate Professor)
Linköpings universitet
---
E-Mail: mik...@isy.liu.se
WWW: http://www.commsys.isy.liu.se/en/staff/mikael
Phone: +46 - (0)13 - 28 1343
Telefax: +46 - (0)13 - 13 9282
Office: Building B, top floor, corridor A, between entrances 27-29.
---
___
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Re: [Discuss-gnuradio] Unable to find USRP[0] issue
Hi Josh, Thanks a lot for the reply. The thing is, I was able to run the benchmark_rx.py and benchmark_tx.py codes in another UHD upgraded daughterboard. That daughter-board module is XCVR2450 transceiver. Unfortunately, I could not run the benchmark programs in the FLEX-400 daughterboard (enabled with Gigabit Ethernet). In both cases, I used the uhd_003_002_001 image. Therefore, does the compatibility issue vary from one daughter-board to another? We need to run the benchmark_rx and benchmark_tx.py programs for our experiments and mostly we have access to FLEX-400 daughterboard. Any suggestion will be highly appreciated. Thanks a lot for the help. Nazmul -- Muhammad Nazmul Islam Graduate Student Electrical Computer Engineering Wireless Information Networking Laboratory Rutgers, USA. ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] USRP1 Ext Clock
What frequency does the USRP1 want to see on its ext clk input? 10 MHz or 64 MHz? @(^.^)@ Ed ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] USRP1 Ext Clock
10-64 MHz http://gnuradio.org/redmine/projects/gnuradio/wiki/USRPClockingNotes -JM On 10/07/2011 09:18 AM, Ed Criscuolo wrote: What frequency does the USRP1 want to see on its ext clk input? 10 MHz or 64 MHz? @(^.^)@ Ed ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Remote Access to USRP testbed with GNU Radio
Thanks a lot for all the replys! Sorry that I forgot to mention I am using USRP2. I think the link is for USRP which create a usrp group for non root control. Best, Guanbo On Oct 7, 2011, at 6:01 AM, Robert McGwier rwmcgw...@gmail.com wrote: I believe people are answering the question but are slightly off target. Create a group on your Linux distribution call USRP, make sure those users you want control the USRP as users (AND NOT ROOT) are in this group. The go read the gnuradio wiki about the other changes granting device permissions etc. This is how remote users gain control of the USRP locally without sudo as well as over SSH whether the machine is accessible over a LAN only or the full internet. Bob On Oct 6, 2011 7:15 PM, Ian Buckley ian.buck...@gmail.com wrote: Remember that you in fact are not required to Login to the USRP at all, it isn't an interactive device, more like a peripheral device to a host computer. Thus your remote access limitation is purely dependent on the remote host you utilize to run GNURadio to interface to the USRP. The main issue you are like to run into is using update intensive GRC graphical tools such as FFT via X or VNC which can be very problematic over WANs. In terms of the USRP itself, if the location is truly remote with no local support then it would be wise to utilize A USRP other than the USRP2 since this model requires the SDCard to be physically replaced to upgrade firmware+FPGA. It would also be wise to have a remote accessible PDU so you can power cycle the USRP if necessary. I've built austere lights out remote satellite ground stations that use USRP's with great success. -Ian On Oct 6, 2011, at 3:31 PM, Kunal Kandekar wrote: I have accessed and used a USRP over SSH before. In fact, I accessed it over the Internet, not just a LAN. Although I was not the one who set it up, as far as I know, nothing additional had to be done to enable this. I simply logged in as the user account under which GNU Radio had been installed. The machine was running Ubuntu, in case it matters. Kunal On Thu, Oct 6, 2011 at 6:04 PM, Guanbo Zheng gbzh...@gmail.com wrote: Hi, all We are interesting to build up a USRP testbed which allowed the guest remote access to do some experiments. I have seen someone's youtube video that they control the USRPs to transmit different signals through SSH access. But I want to double check if it allowed guest control of USRP devices ? Are there any other settings I need to take care of, in order to implement this? Thanks a lot for any suggestions! -- Regards, Guanbo ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] N210 non-uhd?
Can I burn the USRP2 non-UHD firmware on an N210? ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Capture and plot 802.11 frames (Stratos Keranidis)
Hello Mario, thank you very much for your helpful reply. I will try to use the info you provided and infrom you about my progress. Best, Stratos. On Fri, Oct 7, 2011 at 11:00 AM, Mario Gmail mario.ruzr...@gmail.com wrote: Hello Stratos, For capturing 802.11 frames you can take a look here: https://www.cgran.org/wiki/SPAN80211b Unfortunately, that is just for the 802.11b standard. On the other hand, there is one encoder developed for the 802.11g standard, here: https://www.cgran.org/wiki/ftw80211ofdmtx I the last case, I was able to generate 802.11g frames with an USRP2 and detect them with the wifi card in my laptop. That is not what you want but can be a good starting point. Also, I would suggest to take a look to Wireshark (http://www.wireshark.org/) if you want/need to understand all the stuff related with sniffing (i.e, capturing data generated by other equipment). Hope it helps, Mario El 06/10/2011 18:01, discuss-gnuradio-requ...@gnu.org escribió: Re: Capture and plot 802.11 frames (Stratos Keranidis) ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] N210 non-uhd?
No, it won't work. I would strongly suggest you switch to UHD. If that isn't possible, we have some USRP2s which we can sell you. Matt On Fri, Oct 7, 2011 at 10:50 AM, Brett L. Trotter br...@webtrotter.comwrote: Can I burn the USRP2 non-UHD firmware on an N210? ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] New Product Announcements from Ettus Research
On Tue, Oct 4, 2011 at 6:25 PM, Jeffrey Gregory jagre...@umich.edu wrote: The B100 looks appealing for an upgrade from my USRP1, but I have some questions. Since the B100 can accept 10MHz and PPS reference, is it compatible with the GPSDO module? It can accept 10 MHz and PPS from a GPSDO, but it doesn't have a serial port for position and time info. You will also need to mount it externally. So yes, you can use them together, but with some limitations. Also, the Spartan 3A-1400 looks to be roughly twice as big as the cyclone FPGA on the USRP1, is that correct? The two main limitations of the USRP1 for me are the clock stability (minor) and the the FPGA size (more significant). The S3A-1400 has twice as many logic cells. An even bigger difference is that it has 32 hard multiply units, while the cyclone had to use a lot of general logic resources in order to do multiplies. So the capability is more like 3x. The B100 will have much better clock stability (~2.5ppm over temperature) even without the GPSDO. Matt ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] Updated build-gnuradio
One of my users in Guatemala found an issue with the build-gnuradio script. If your system is configured for anything other than English, the script fails, because it's parsing the output of ls -l, and looking for a Not found error message. Which of course, will only happen if the systems message library is set for English. Fixed. Who knew? -- Marcus Leech Principal Investigator Shirleys Bay Radio Astronomy Consortium http://www.sbrac.org ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
Re: [Discuss-gnuradio] Cheap portable antenna for SSB + CW w/ USRP1?
On Oct 7, 2011, at 11:01 AM, discuss-gnuradio-requ...@gnu.org wrote: [Discuss-gnuradio] Cheap portable antenna for SSB + CW w/ USRP1? Since you are only interested in RX, a loop would probably work well. You could probably rig up compact, muti-turn wire loop that could be broken down and folded. A simple passive loop requires a high-Q, variable plate capacitor you must tune for resonance, so it is inherently narrow band, but that also gives you rejection. They are lossy too, but HF is dominated by atmospheric noise so noise figure is not a prime concern. MFJ-952 is a mini-loop tuner; just add your own wire. There are active loops too. This is a list: http://homepages.tig.com.au/~vk5vka/antnews.htm Active loop design: http://sivantoledotech.wordpress.com/2010/09/18/a-tuned-active-receiving-loop/ ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
[Discuss-gnuradio] file source/sinks and named pipes
I have tried the following experiment that generated a couple of puzzling questions for me... A graph consisting of a sinusodial source, a file sink and a graphical fft sink (connected to the source). NO THROTTLE is present in this graph A separate graph with a file source, a THROTTLE at 100K and a graphical fft sink I creat a named pipe with mkfifo myfifo and both tx and rx are writting/reading to/from this pipe. I run first the rx file and then (in a separate shell) the tx file. Everything works as expected, ie both graphs seem to be working at the same rate. The reason (as I understand it) is the the rx file (containing the throttle) consumes data from the fifo at 100K and this INDIRECTLY sets the rate of the tx due to blocking of the tx when the fifo fills up (I read that Linux has a 64K buffer for the fifo). This is also evident from the system load which stays relatively low. Q1: Is this the reason the two grahs are synchronized, or is it that the throttle in the rx DIRECTLY sets the rate for the tx? Now I do the following: I stop the rx for roughly 10seconds and then I restart it. During those 10 seconds the system load shoots to 100% which is to be expected since the tx does not have any throttle... However I would ALSO expect that during those 10seconds the pipe buffer fills up and it blocks the tx, and so the tx eventually stops and waits for the rx to be restarted and start consuming samples from the pipe, which is somethig I do not observe!!! Instead what I see is that the moment I restart the rx the load drops somewhat for about 90seconds and then drops furthermore to the original levels (observed when both rx and tx are running). Q2: what happens to the tx and the named pipe when i stop the rx? and why does in not fill and stop? Thanks Achilleas ___ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
