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AD9912 SYSCLK connection for best perfomanse

Question asked by AlexandrBAM on May 20, 2016
Latest reply on Jun 2, 2016 by JLKeip


I use AD9912 on mine evaluation board. As system clock i use crystal generator AOCJY-A 38,4 MHz. Unlike to recomended Vectron generator it has no differential output.

I tried to connect it in different ways: thru transformer ETC1-1-13, without transformer just to SYSCLK line, and connected SYSCLK and SYSCLKB with 100 Ohm resistor.

Anyway, it work's, but what connection is best? In my opinion, connection thru transformes is best.

Besides, i have very strong mirror signals, separated on 38,4 MHz from main signal. Should filter between generator and SYSCLK line solve this problem?

Why could be so high noise level near main signal?

I attach few measurement files. Signal measured on out of 400 MHz reconstruction filter.

Best regards, Alex.