AD7176-2 has unknown noise in sample data.

Hi ADI,

I got EVAL-AD7176-2SDZ (Rev-A), and I use it to test audio signal.

I use AD7176-2 to sample a pure 12.5 kHz 0.1 Vrms sine wave, and sample rate is 125kHz.

But there is a stable low frequency noise as below picture, so it make the wave envelope is unstable.

I

My setting as below:

The attachment is my test data.

Do you have any idea about this problem?

Thanks.

Homeway

12.5kHz.csv.zip