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Tx Quad Calibration

Question asked by lnreddy123 on Mar 24, 2015
Latest reply on Mar 27, 2015 by tlili

Hi ,

 

I have followed the steps as described in the following thread.

https://ez.analog.com/docs/DOC-3143

 

I have manually configured the rx_phase value using the following command.

root:/sys/bus/iio/devices/iio:device1> echo tx_quad 14 > calib_mode. The best fit value was 21 and corresponds to the value used in the static int32_t ad9361_tx_quad_calib(struct ad9361_rf_phy *phy, function of ad9361.c file.


I am using the IIO oscilloscope to generate the single tone of frequency kHz. I can see that the best suppression of image is around 40 dB for kHz tones. However for MHz tone , I have seen 50 dB suppression. I have used the LTE profile files (3,5,10 and MHz) for bandwidth and sampling frequency configurations.


Attached are the screen shots of spectrum Analyser plots.Is this best image suppression we can get for IQ phase and gain errors.


The transmit center frequency is 800 MHz and I have used a low pass filter (DC-1GHz) to remove the harmonics on Tx.



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