How to disable NI 5752 anti-alias filter

[Alberto Martin]

Hi all!

I have a question concerning the digitizer NI-5752 which has a anti-aliasing filter of 7.5, 10 or 14 MHz. I was wondering if I can disable this filter for acquiring the data. Considering its 50MSs, we are able to digitize till 25MHz, but if we get this 14MHz filter, we loss a lot of information right?

Thank you for the response.

Regards,

Alberto

[TobiD]

Hi Alberto,

im not sure about the 5752 but for the the NI-51* Series this can be done. See this KB

Please let me know if this works for the 5752 as well

Regards,

Tobias

[dansch]

Hi Alberto and Tobias,

The NI 5752 is a NI FlexRIO™ digitizer adapter module, and so it is a bit different than most 51xx/56xx/59xx digitizers which use NI-SCOPE. Most of the configurable settings on the NI 5752 depend on the TI AFE5801 chip that the NI 5752 is built upon. While you are correct that the Nyquist frequency is 25 MHz, the AFE5801 chip only has options for 7.5, 10, and 14 MHz anti-aliasing filters (AAF). Unfortunately, this AAF cannot be disabled so 14 MHz is the maximum bandwidth of the chip. According to the AFE5801 spec sheet, you will have -6 dB of attenuation @ 20 MHz and -12 dB of attenuation @ 30 MHz with the 14 MHz filter selected. Hope this helps,

[Alberto Martin]

Thank you both Tobias and Daniel. Now everything is clear.

Regards,

Alberto