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ADL5380 spur issue

Question asked by yckim on Mar 12, 2018
Latest reply on Apr 25, 2018 by dmailloux

Hello,

I'm using ADL5380ACPZ for downconversion RF signal as 1~6GHz to Baseband signal 5~80Mhz. It's direct conversion.

When I tested EVAL board as A02029C-7. Sometime I need to move RF from LO frequency over 500Mhz. Because I have to measure adjacent channel that it would be noise floor or other channel. And there is some problem... there is 20Mhz spur. I'm using RF signal that modulated OFDM.. I can see OFDM sub carrier.....

ex... LO frequency is 5795MHz and RF is 4000MHz (802.11ac BWW40MHz OFDM) 

IF shoud be clear... but offset 20MHz... there is OFDM sub carrier.. plus It's happend only upper BW40MHz or 80MHz.

BW 20Mhz doen's make spur.... of course It's very small signal... If I make Rx spectrum mask, so need to measure noise floor. It could be a problem...

If you have any information. Please let me know.

 

Thank you.

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