This post is for the archive. This post was addressed in some later posts: http://lists.gnu.org/archive/html/discuss-gnuradio/2018-05/msg00059.html http://lists.gnu.org/archive/html/discuss-gnuradio/2018-05/msg00194.html http://lists.gnu.org/archive/html/discuss-gnuradio/2018-04/msg00207.html
Inkyu, if you still have any outstanding questions, then please start a brand-new thread. --​Neel Pandeya On 3 May 2018 at 20:49, Inkyu Bang <[email protected]> wrote: > Hi, all > > I am trying to calibrate frequency offset between Tx and Rx (USRP B210) by > manually using GRC. > > First, I have checked self RF-calibration UHD functions but it seems B210 > does that internally. > ref: http://lists.ettus.com/pipermail/usrp-users_lists. > ettus.com/2016-June/020750.html > > > *Q1) How can we compensate some frequency offset between Tx and Rx devices > using GRC?Is there any simple way to do this?* > > For this, what I have tried is to send simple sine wave and then checked > how the frequency of sine wave is changed at the receiver side. > > For example, I sent "sin(f0)" using a carrier frequency "fc" and I > received "sin(f0+f_delta)" > > I can clearly see f_delta using QT_GUI_TIME_SINK block. > sampling rate: 5MHz > center frequency (fc): 5.89G > signal frequency (f0): 5000Hz > tx signal (5 peaks): https://imgur.com/r8BXGI2 > rx signal (6 peaks): https://imgur.com/NO462Vd > > To figure out the f_delta, I tried to use FFT (QT_GUI_FREQUENCY_SINK) but > it's hard to figure out f_delta for me (I used 8192 FFT size). > > *Q2) Can anyone help to solve this problem?* > > The last question, > > I transmit simple sine wave using different USRPs (separately). > it shows different received signals. > (i.e., USRP1 to USRP_rx or USRP2 to USRP_rx) > > *Q3) Is it simply due to different tx frequency offset between two devices > (USRP 1/ USRP 2)?* > > sampling rate: 5MHz > center frequency (fc): 5.89G > signal frequency (f0): 500Hz > tx signal (USRP1): https://imgur.com/SCW8dAX > rx signal: https://imgur.com/AvplL8O > > tx signal (USRP2): https://imgur.com/SCW8dAX > rx signal: https://imgur.com/w5ER332 > > Thank you, > Regards, > > Inkyu > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio > >
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