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ad9361_TX Spectrum

Question asked by 王梦达 on May 17, 2017
Latest reply on Jun 6, 2017 by 王梦达

Hello, I am now studying ad9361 data launches.The I data and Q data are generated by matlab.The code is shown below。

      N=16384;

      f0=1*10^6;

      fs=4*10^6;

      t=0:1:(fs/f0)*N-1;

      I=cos(2*pi*f0/fs*t);   Q=sin(2*pi*f0/fs*t);

The filter coefficients are configured as follows:

TX: LVDS, FDD, DDR. The fb_clk is data_clk from the ad9361.The LO is 120M.

Now, thespecturm of  output of AD9361 is as follow.

 

The spectrum has three components : 116M,120M,124M. 

There is two questions.

1.The configured filter coefficients are correct?

2.Why spectrum has three components?

I hope you can give me some advice!Thank you!

 

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