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AD9361 IIP3

Question asked by sanford on Nov 9, 2015
Latest reply on Nov 9, 2015 by tlili

My questions are regarding the AD9361 transceiver IIP3

 

1) Figure 12 of the specification shows the IIP3 vs Rx gain index  as varying between +10 dBm at a gain index of 20 dB to -18 dBm at a gain index of 76 dB with cariers at 1.45 Mhz and 2.89 MHz. The 3rd order IM will be at at either  10 kHz or 4.34 MHz  Is the IIP3 levels in the figure based on an IM inside the 3 dB BW of the Rx TIA LPF and Rx BB LPF, or is outside the 3 dB BW? If it is outside the 3 dB BW,  what is the 3 dB BWs that was used for this data, and how much rejection from these filters does the IM see? If it is inband, then with a -18 dBm IIP3 and a gain of 76, the OIP3 will be 58 dBm or 631 W. This does not sound likely for an inband IM.

2) If the data in Figure 10 is for an OOB IM, what is the IIP3  for an inband 3rd order IM  vs Rx gain index? If a full curve vs gain index is not available a few values in the gain index of 60 to 75 range would suffice.

3) What is the carrier frequency dependency of the IIP3  for an inband 3rd order IM? Is it just a function of the change in gain vs carrier frequency.

 

Sanford

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