Waveforms Spectrum Multiple Issues with Noise Density

[DTM_RD3]

Hi!

Please See attached Waveforms Project. Im using the ADP5250. I'm having some troubles when selecting voltage noise density v/sqrt(Hz) as units:

1. A marker wont set onto the trace:
   
2. Average Measurement always displays 0:
   
3. I cant't get rid of two spikes, they seem to come from inside the ADP5250.
   

The spikes from the last point would be tolerable if I could somehow make a base noise measurement and then subtract it from my noise measurement. However, I haven't figured out how to make mathematical calculations with ref traces in spectrum view. Keep in mind that I'd need to subtract it under square root, because thats how noise densities are summed up.

Regards,

M.

buggy_AD_PRO.dwf3work

Edited January 23 by DTM_RD3

[attila]

Hi @DTM_RD3

The marker and some measurement magnitudes are rounded to 3 decimals, so smaller values are displayed as 0s.

Thank you for the observation. It will be fixed in the next version.

[DTM_RD3]

Excellent Response Time! Thank you for fixing this!

Is there any way to enable me to make a arbitrary mathematical operation between two traces in FFT?

For instance, if I measured system noise and stored it in a reference trace ref1,  I could get the DUTs noise from a measurement on channel C1 by doing:

dut_noise_density = sqrt(pow(C1,2) - pow(ref1,2))

In the FFT window i'm somewhat missing the math flexibilty i'm used from the scope window.

Edited January 23 by DTM_RD3

[attila]

Hi @DTM_RD3

The next version will add Math to Spectrum.

[DTM_RD3]

This is incredible support. Thank you a lot!!