I am facing another problem in (fsk_tx.py, fsk_rx.py) , At receive end it do not always write the received data to file. Although it always receive signal which I can see from fft window and received 'seqno' are also printed on command prompt but when I check the received file I find it empty.
What can be the problem....??????? Kaleem Ahmad Firas A. wrote: > > Hi, > > > 1) See : > http://gnuradio.org/trac/wiki/UsrpFAQ > http://gnuradio.org/trac/wiki/UsrpFAQ/Clocking > http://gnuradio.org/trac/wiki/UsrpFAQ/Gen > > 2) To make nearly 0 Hz frequency shift between your TX and RX you have to > use a third device Spectrum analyzer or third USRP (no need to warry about > its calibration since the error will be the same for both) as follows: > > a) Start transmitting single tone from TX USRP (using usrp_siggen.py) > > b) Observe and record spectrum analyzer received tone frequency. > > c) Stop TX USRP. > > d) Start transmitting single tone from your RX USRP (using > usrp_siggen.py). > > e) Observe spectrum analyzer received tone frequency. Adjust your > transmitting frequency from your RX USRP until you get exactly the same > value found in step-b > > > 3) I appolagize about my previous post so many spelling errors!. > > > Regards to all, > > Firas > > > --- On Thu, 7/24/08, kaleem ahmad <[EMAIL PROTECTED]> wrote: > From: kaleem ahmad <[EMAIL PROTECTED]> > Subject: Re: [Discuss-gnuradio] FSK with RFX2400 > To: Discuss-gnuradio@gnu.org > Date: Thursday, July 24, 2008, 5:07 PM > > Hi, > > Can some one explain in a little bit detail about where is the clock or > oscillator (on daughter board or on mother board) and how much is its > resulution for RFX2400 daughter board. > > I tried to solve the problem of frequency mismatching by calculating the > frequency shift at receiver end by using usrp_fft.py and then by > adding/subtracting that frequency from RX USRP frequency as explained by > Firas and Patrick. But it dont solve the problem although it improves the > quality of data but because of this effort at least I understand that the > problem is really some where because of frequency mismatching. > > So it will be helpful for me if some one either give some good document of > USRP explaining clock/oscillator or just explaing the fuctionality of it > by > him/her self. > > Thanks > > > > Firas A. wrote: >> >> Hi Kaleem, >> >> Each USRP has its on reference crystal oscillator. This oscillator may >> have maximum +/- 50 PPM ( Matt said the new USRPs has maximum 20 PPM) >> frequency error. Lets assume the error is 10 PPM in each USRP. This >> means, >> that at 2500 MHz (2.5 GHz) the error = 2500 * 10 = 25000 Hz = 25KHz. >> >> Now imagine that the first USRP has +25 KHz frequency deviation error and >> the second one has - 25KHz frequency error. This means + 50 KHz frequency >> mismtch between your TX and Rx Frequencies. This is probably what is >> causing this high error rate that you see. >> >> To solve this problem you simply do : >> >> 1) Use usrp_siggen.py to send single tone at F1 frequency (For example, >> use F1 = 2475 MHz) from your TX USRP. The best thing is F1 be the >> frequency used in your FSK experiments. >> >> 2) With your RX USRP, start usrp_fft.py with frequency F1 and decimation= >> 128 (or 256). You should see your transmitted tone but may be it's >> frequency is shifted. Calculate this frequency shift. >> >> 3) Add/subtract this frequency shift to your RX USRP frequency tunning >> function. >> >> 4) Now your two USRPs frequency mismatch should not be the problem. If >> the >> errors is still there, then you have to search for another reason. >> >> Regards, >> >> Firas >> >> >> >> --- On Wed, 7/23/08, kaleem ahmad <[EMAIL PROTECTED]> wrote: >> From: kaleem ahmad <[EMAIL PROTECTED]> >> Subject: Re: [Discuss-gnuradio] FSK with RFX2400 >> To: Discuss-gnuradio@gnu.org >> Date: Wednesday, July 23, 2008, 5:23 PM >> >> I have just provided the information which can be helpful for you, and >> the >> code is also attached with it and a sample received file is also there >> along >> with actual sent file. >> >> Please just scroll up and you will find my message with all this >> information. Additionally OS is 'openSUSI' a favour of Linux. But > if >> you >> still need some more info then please let me know. >> >> Thaks >> >> >> >> Patrick Strasser wrote: >>> >>> kaleem ahmad wrote am 2008-07-23 11:38: >>>> Dear All, >>>> >>>> Can anyone also address the first part of my question aslo, I mean > how >> to >>>> improve the quality of received data. I mean is it normal with GNU >>>> Radio/USRP that we receive so currupt data or I am doing something >> wrong. >>>> Any suggestion please >>> >>> Before you wrote >>> >>>> after using tune >>>> to set the proper ferquency I was able to run transmitter and > receiver >>> > sussfully. I didnt change anything else in the example. >>> > The problem is data >>>> which I receive is too much corrupt (lot of data errors).. >>> >>> Your description is not very exact. You could help us to help you with > >>> more information: >>> >>> What is your setup? OS, distribution, used version of packages, GNU >>> Radio, hardware setup, used parts (cable, antennas), environment. >>> What do you do? Which code do you use? >>> What did you change? >>> What did you get? Error messages? (add _exact_ transcripts of errors) >>> What did you expect? >>> Please provide exact information, code should be attached. If you >>> changed something, mark the changes so helpers will find it easier. >>> >>> If you have recorded samples of a good and bad transmissions, send us > a >>> representative part of it. If you need to show more than a hand full > of >>> kilobytes, put them on a web server or ftp server and provide a link. >>> >>> Are you sure to have read the FAQ and introducing documentation? >>> >>> Patrick >>> -- >>> Engineers motto: cheap, good, fast: choose any two >>> Patrick Strasser <patrick dot strasser at student dot tugraz dot > at> >>> Student of Telematik, Techn. University Graz, Austria >>> >>> >>> >>> _______________________________________________ >>> Discuss-gnuradio mailing list >>> Discuss-gnuradio@gnu.org >>> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio >>> >>> >> >> -- >> View this message in context: >> http://www.nabble.com/FSK-with-RFX2400-tp18587205p18611871.html >> Sent from the GnuRadio mailing list archive at Nabble.com. >> >> >> >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> _______________________________________________ >> Discuss-gnuradio mailing list >> Discuss-gnuradio@gnu.org >> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio >> >> > > -- > View this message in context: > http://www.nabble.com/FSK-with-RFX2400-tp18587205p18632632.html > Sent from the GnuRadio mailing list archive at Nabble.com. > > > > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > _______________________________________________ > Discuss-gnuradio mailing list > Discuss-gnuradio@gnu.org > http://lists.gnu.org/mailman/listinfo/discuss-gnuradio > > -- View this message in context: http://www.nabble.com/FSK-with-RFX2400-tp18587205p18652907.html Sent from the GnuRadio mailing list archive at Nabble.com. _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
