DAC5681: Measure SNR

Valentin,

We are looking into this.

Regards,

Jim

Valentin,

SNR should be calculated using a noise spectral density measurement (NSD). For this data sheet, the NSD value is called out as "Noise floor". The noise value needs to be converted to dbc/Hz then integrated over the Nyquist bandwidth. The SNR value shown in the data sheet may or may not include the spurs over this range. 

Regards,

Jim 

jim s said:

The noise value needs to be converted to dbc/Hz then integrated over the Nyquist bandwidth

Is anywhere an example how it can be calculate?

Valentin,

See attached documents.

Regards,

Jim

DAC basics.pdfDAC Concepts.pptx

I apologize in advance, but I did not find the right formula. Could you show it?

In the DAC Basic Concepts document, this is in section 2 starting at the bottom of page 3.

Jim  

So If I use this formula SNR = 10log10(-5/-95)=12.8 dB. I think that it's incorrect result and use only this formula is wrong.