Hi,

I am using AD9208 for one of my application.

The aperture jitter for AD9208 is mentioned as 55 fSecond in the datasheet.

I want to convert this number to phase noise in dBc/Hz.

Once I convert jitter to Integrated Noise, over what band width I should normalize it to get dBc/Hz number?

I am trying to evaluate effect of ADC jitter on the output sampled signal's phase noise.

I am going to use formula

Integrated Phase Noise = 10*Log[ {(Aperture Jitter * 2*PI*Fs)^2} / 2]

Let me know if any modification to the formula is needed.

Regards,

Dwijen

Hi Dwijen,

Ideally you would want to integrate the phase noise as high as you can go, to get the rms jitter number. The 55fs is a derived number that also matches the math we get from simulations. What we do is to do analog input sweeps and then curve fit it into the graph below.

This information is available in the datasheet. Once we have the curve fit, then it is a mere exercise in math to extract out the individual jitter components.

Here is some additional reading that will help

http://www.analog.com/media/en/technical-documentation/application-notes/AN-1386.pdf

Clocking Wideband GSPS JESD204B ADCs | Analog Devices

http://www.analog.com/media/en/technical-documentation/application-notes/AN-756.pdf

Thanks

Umesh