AnsweredAssumed Answered

AD9694 Full Bandwidth Mode operation.

Question asked by SKBY on Dec 14, 2016
Latest reply on Jan 23, 2017 by SKBY

Dear Experts,

 

My customer wants to ask you about the following questions related to "Full Bandwidth Mode" in AD9694. Could you please reply to the following questions?

[Customer's AD9694 usage]:
1) Sampling rate: 250[Msps].
2) ADC channels: 4 channel used.
3) All DDCs: Disabled.
4) ADC bandwidth: DC to 125[MHz].
5) Analog signal bandwidth: The 2nd Nyquist frequency at 125[MHz] to 250[MHz] for RF IF signal.


Q1: When Bit[3:0] in Register 0x0200 is set to "0000"(b) as "Full bandwidth mode" in AD9694, can 4ch ADC sections in AD9694, correctly and individually, work with 250[Msps] for 0 to 125[MHz] as full bandwidth mode?

Let me show you the following reason why my customer asked you about the above question:
* p.57 of AD9694:
- Two 14-bit converters at 500MSPS.


Q2: There is "NSR (21% OR 28% BANDWIDTH)" in "Figure 92 Full Bandwidth Mode" on p.57 of AD9694 datasheet.

What is "NSR"? "NSR" is "Noise Shaping Re-quantization", isn't it?

 

Q3: Moreover, please advise my customer about the meaning of "21% OR 28% BANDWIDTH" in the above NSR block of AD9694..

 

My customer is worried that the NSR might make more bandwidth limitations for "0 to 125[MHz]" with 250[Msps] even in Full bandwidth mode of AD9694.

 

Thanks and regards.

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