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AD9361 Rx Signal Harmonics

Question asked by semion_z on Dec 20, 2016
Latest reply on May 2, 2017 by Vinod

Hello

 

I work with 2 AD9361 devices using No-OS drivers.

When I inject a 600 KHz CW signal to AD9361 Rx channels from external signal generator I see many harmonics of this signal as can be observed on the following figure: 

 

The following are the relevant system parameters:

 

1. RF Frequency=2920 MHz

2. Signal input power=-40 dB

3. Rx gain=20 dB

4. FIR Filter is used and defined as following:

 

 

AD9361_RXFIRConfig HB_rx_fir_config = {

                3, // rx;

                0, // rx_gain;

                1, // rx_dec;

            {5236,-16972,17634,-5964,-5070,3152,-60,-3023,-306,46,-1742,-1053,-70,-782,-649,362,445,539,1503,2091,2338,3199,4047,4415,5110,5972,6341,6763,7436,7664,7723,8058,8058,7723,7664,7436,6763,6341,5972,5110,4415,4047,3199,2338,2091,1503,539,445,362,-649,-782,-70,-1053,-1742,46,-306,-3023,-60,3152,-5070,-5964,17634,-16972,5236},

                 64 // rx_coef_size

};

 

 

The Tx signal generator signal has been checked using spectrum analyzer and has been found as very clean one.

 

What can be reason for this issue and how can it be solved?

Thanks in advance.

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