AD9208 acquisition noise has a high noise floor

Hi penny102 ,

I will move this thread to the proper forum. Someone there should be able to assist you.

Regards,

JC

Thanks for your help.

Hi Penny,

Please see Extremely high noise on AD9694 output samples with input disconnected - Q&A - High-Speed ADCs - EngineerZone (analog.com)

Before that, Could you run the ADC test modes to make sure that the JESD links are working reliably. They're available in Register 0x550. These tests can be performed with or without an analog signal (if present, the analog signal is ignored).

Regards,

Alvin

Thanks， We'll try to use test modes to test，and then  give you a  reply.

Hi Brother ：We tried to use test mode and found that JESD couldn't link.

Hi Penny,

Based on your JESD configuration, F=1，M=1，L=8，N=14，N’=16，K=32, I assume you are running 1-channel full-bandwidth mode and no DDC used.
The purpose to run the test mode is to verify whether your JESD interface is good or not.  So, please enable the test mode after link is established.

Besides, could you share your register writing for ADC test mode?

Regards,

Alvin

Register as shown in the figure 

Hi Penny,

I just quick checked the register 0x550 for test mode setting, it is still 0x00, could you confirm which register was be written when you do the test mode test?

Regards,

Alvin

This is assumed to be fixed. Please let us know if you have further question about this.

Regards,

Alvin

We have set 0x03 to the register 0x550, then we got value with -8192 by all channel. In addition, we tried to slow down the sample rate to 1.2G,and we got value  -6000 in range ±100 with no input. and in this condition.