NI-PXIE-FGEN 5451 Dynamic performance

[sagar7077bishwas]

Hi team,

Below image is the spectrum for 10MHz sine wave from NI-PXIE-5451 form the datasheet,here the noise floor is below -70db.

below images are the loop back spectrum of FGEN -5451(generating instrument) NI-PXIE-6363-AI (capturing instrument for the frequencies of 10khz,20khz and 50khz.

from the loop back spectrum spurs are observed near -75db for this much less frequencies (10khz,20khz and 50khz) from the 80Mhz generating instrument.

could you please help to identify the what could have gone wrong for this worse noise floor?

Regards,

Muhammed Esa A

[santo_13]

Now, the question is whether 6363 has a better noise floor to measure that of 5451. I don't see any of the AC signal specs at 6363 datasheet.

You always need a better instrument than what you're trying to measure. Please measure the noise floor of 6363 with shorted AI channel to AIGND, this must be better than what you're trying to measure.