we are using AD9371 eva board, after giving input -5dBm to its input RX1 the overall impedance of the RX1 is out now. i know the max input should be -14 dBm but i gave -5dBm because AGCs were working fine. i am using Network analyzer to check the impedance RX2 is 50-52 ohms but RX1 is 120-140 ohms, i have replaced the balun too but it didn't improve at all, i also replaced 10pF and 82pF capacitors attached with balun to see if they got devalued but nothing changed can you plz suggest me any solution? or this is a permanent damage to AD9371 IC?
Are you using TES or IIO scope GUI?
Are you able to program/initialize the board from GUI?
Please make sure that you are enabling both the Rx1 and Rx2 channels?
Are you seeing any difference in Rx gain between Rx1 and Rx2 channels?
i am using a network analyzer on Eval board,
i have program the board by generating C files from TES GUI and placing them in no-OS files and make .bin file and programmed the FPGA with it, whole system was working just fine before giving -5dBm input.
now the Input impedance is changed what should i do now?
i am not sure about gains, but the sensitivity of both Receivers are changed now, Rx1 (bad impedance) has -43 dBm while Rx2 has -74 dBm (using an external amplifier of 14 dB gain on both receivers).
Can you share the wideband S parameter plots(check the output where you get the best match from the plots)? Also, can you check the insertion loss from antenna port to Balun input? It can be because of some physical damage on the path as it was working previously.
i just talk to RF engineer, they have added a 85 ohms resistor at input to compensate the high impedance,
this is the n/w plot our center frequency is 1.03GHz and its 100MHz spam plot.
without that resistor impedance at this frequency will jump to 100+ ohms (this is RX1).
RX2 is just fine here is the plot of RX2 without any issue
as you can see RX2 slop is quite smooth while RX1 has high variations.
giving -5Bm should not cause any physical damage because AGC were On and did test this hardware before on 0dBm input too.
can you plz suggest anything now?