AnsweredAssumed Answered

LO leakage in AD9364 Tx test

Question asked by jinojs on Nov 3, 2014
Latest reply on Nov 10, 2014 by DragosB

Hi,

 

I'm performing the Tx tests using the No-OS reference design of AD9364.

 

I have configured LO frequency to 700MHz and sinewave (DDS) at 2MHz, but at the spectrum analyzer, the observed tones are at 1MHz apart from the center frequency. Expected at 702 and 698MHz but observed at 701 and 699MHz.

Screen_500_0006.png

 

Sinewave is configured to 2MHz using below line in dac_init function:

case DATA_SEL_DDS:

  dds_default_setup(phy, DDS_CHAN_TX1_I_F1, 90000, 2000000, 250000);

  dds_default_setup(phy, DDS_CHAN_TX1_I_F2, 90000, 2000000, 250000);

  dds_default_setup(phy, DDS_CHAN_TX1_Q_F1, 0, 2000000, 250000);

  dds_default_setup(phy, DDS_CHAN_TX1_Q_F2, 0, 2000000, 250000);

 

LO frequency is configured to 700MHz using below lines in 'AD9361_InitParam default_init_param = {' in main.c

/* LO Control */

  700000000UL, //rx_synthesizer_frequency_hz *** adi,rx-synthesizer-frequency-hz

  700000000UL, //tx_synthesizer_frequency_hz *** adi,tx-synthesizer-frequency-hz

 

This is observed for different combinations of LO (700MHz, 830MHz) and sinewave (500KHz, 1MHz, 2MHz) frequencies.

Please guide me how I can fix it.

 

Thank you,

~Jinoj

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