Products In This Thread

AD9208 Recommended for New Designs
The AD9208 is a dual, 14-bit, 3 GSPS analog-to-digital converter (ADC). The device has an on-chip buffer and a sample-and- hold circuit designed for low...
Datasheet
AD9208 on Analog.com

AD9208: Harmonic of Decimated FS mixes with NCO

Dwijen.Pandya

on Dec 19, 2017

Hi,

I am using AD9208 for one of my application. I am using AD9208-3000EBZ+ADS7-V2EBZ for the evaluation

In my setup Fs is 3GHz

Decimation Rate is 8

Decimated Fout (Decimated Fs) is 375MHz (3GHz/8)

NCO is 702MHz

RF In to the ADC is 800MHz

I have observed that there is spur in the output spectrum that is arising from mixing of the harmonic of Fout with NCO.

For the above setup there is spur at 48MHz.

2*375MHz - 702MHz = 48MHz

The snapshot of the ACE setup and the output spectrum is attached.

Is this spur expected? What can be done to minimize this spur?

Regards,

Dwijen

Parents

UmeshJ
on Dec 20, 2017 10:41 PM
Hi Dwijen,

Can you please give me some more information on your test setup? You are using the MXG to generate the tone. Are you using any filter in between the MXG and the ADC's input? If so what is it?

Can you also send me a screenshot of the same signal with the DDCs bypassed (full BW mode)? The setup for that is shown below. You can also find the setup in the wiki user guide.

Thanks

Umesh
Cancel
Up 0 Down

Reply

Cancel

Reply

UmeshJ
on Dec 20, 2017 10:41 PM
Hi Dwijen,

Can you please give me some more information on your test setup? You are using the MXG to generate the tone. Are you using any filter in between the MXG and the ADC's input? If so what is it?

Can you also send me a screenshot of the same signal with the DDCs bypassed (full BW mode)? The setup for that is shown below. You can also find the setup in the wiki user guide.

Thanks

Umesh
Cancel
Up 0 Down

Reply

Cancel

Children

No Data