AD9176: Signal source for phase noise evaluation

Question

Hello,

I have a question from our customer about the signal source for AD9176.
He asks me what signal source was used when evaluating the phase noise of AD9176 of direct clock mode.
The SSB phase noise performance of direct clock mode is indicated in the datasheet Figure 38.

Q1. He wants to know what signal generator was used to get the performance. (for example, Rohde & Schwarz SMA 100B Opt.B711)
Q2. Was AD9176-FMC-EBZ used to evaluate phase noise of direct clock mode? Or another special board for phase noise evaluation to input high frequency(12GHz) clock was used?

Best regards,

y_suzuki

Biao.H · Accepted Answer

Hi y_suzuki, 
 Q1: it's SMA100B with ultra low phase noise option. the key is to ensure phase noise is low enough to ensure the phase noise contribution from clock source can be ignored. 
 Q2, the internal engineering board and AD9176-FMC-EBZ have very minor difference on the phase noise. the customer could use the AD9176-FMC-EBZ for phase noise evaluation. 
 some extra comments. when measuring the phase noise at the DAC output, it's impacted by, 
 1) clock source phase noise. 
 2) power supplies phase noise. especially clock power supply and then analog power supplies. 
 3)DAC itself phase noise. 
 so for the best #3, the #1 and #2 contributions should be minimized with high qualify clock sources and power supplies. 
 hope it helps.

Electronic Design Services - PartnerZone

AD9176: Signal source for phase noise evaluation

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