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
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