Hi, I wanted to understand this API, mainly the third argument.
int32_t ad9361_do_calib(struct ad9361_rf_phy *phy, uint32_t cal, int32_t arg);In documents the description is given as,Performs the selected calibration. Receives as parameters a structure that contains the AD9361 current state, the desired calibration (TX_QUAD_CAL, RFDC_CAL) and for TX_QUAD_CAL, the optional RX phase value overwrite (set to zero). Returns 0 in case of success, negative error code otherwise.What exactly does the third argument used for? On what basis this value is decided. Please shed some light on this.
The second argument specifies the calibration that is selected for running and the third argument specifies the RX phase value that is used for TX quad cal(the phase value is used only if TX quad cal is selected in the second argument. The default phase value is set to zero).
I have reduced the LO leakage and also carrier image component upto 50dBc down using this. Now I am getting a third harmonic image component inside the band which is 30 to 35dBc down which is not expected.
I don't know if this is because of any of the block in the transmitter path that is getting saturated. Digital filters are not being used in the transmit path, they are currently disabled. The transmitter output signal when observed in the spectrum analyzer looks fine but this harmonic peak is disturbing. Output power in analyzer is showing around 7 to 8dBm.
We are using full 12bits swing i.e. we are generating a 12 bit signed signal which is having swing from -2048 to +2047 from a DDS in fpga and then we are feeding it to the transmitt path. Should we do anything additional other than this? like always keeping lsb 4bits to zeros so that instead of full swing it will be reduce by value 16, or should we monitor any overflow flags in transmit path to make sure that no block is getting saturated.
Kindly throw some light on this.
You can readback the overflow registers(0x5E-0x5F) or you can try by decreasing the amplitude of the signal to check if the path is getting saturated or not.