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AD9361 - LMT detector level

Question asked by idan_ar@eyal-emi.co.il on May 28, 2014
Latest reply on Jun 2, 2014 by tlili

I'm trying to config the LMT detector of the AD9361 - on the AD-FMCOMMS3-EBZ mounted on ZC-706REV 1.2 board.

I familiar with the calculation formula for the level detect:

 

                        ℎ      ℎ      (            )= 16     ×(                        ℎ      ℎ      [5:0] +1)

 

 

when translate to dBm there is an issue with the translation.

I'm working with gain 70 dB and 18 MHz RF BW. I set a signal 40MHz higher and set the large LMT overload to 100 mV RMS - Translation to dBm is -10 dBm.

LMT gain should be 49 dB - ~10 (TIA filtering)= ~39 dB.

 

The overload large LMT 100mV. The large overload LMT  indication indicate to "1" with input power of -48 dBm. up now everything is OK.

 

Please explain the 6 Bit register 0x107, 0x108 - the max. val can be 1.024V => ~28 dBm. Does the AD9361 LNA and mixer support those levels?

 

  1. Is it safe to set the limit so high and what is the max. input power out o band for the LNA and mixer.
  2. Can you please provide typical TIA filter shape? for each BBBW...

 

Thanks,

Idan.


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