USB 6259 Anti Aliasing filter

[fsouto]

Hello, I am trying to acquire analgo data from 9 different channels using the USB 6259 DAQ system. I am interested in a low frequency ( 500Hz) band and my sampling frequency is 5000 samples per second. I want to filter the analog input to avoid aliasing frequencies.

I am a little short on time, and I dont have time to design an anti alias filter my self. Is there an external anti alias filter i can get for the USB 6359?

I found the NI SCC signal conditioning system, but not sure if it will work with the USB 6259?

Thank you for your time and attention  

[Andrew_B]

Hello fsouto,

This is Andrew Brown, an Applications Engineer from National Instruments. The SCC system is absolutely an option to perform external anti-aliasing filtering wth your USB 6259 (an M Series module). You will also need a SH68-68 or related cable.

Another option you can consider is software filtering the signal using LabVIEW or SignalExpress. One example functions that would perform this purpose include the Filter Express VI.

Please let me know if you have additional related questions.

Regards,

Andrew Brown

[fsouto]

Hi Andrew, 

thank you very much for your quick response. I read the recommended articles, but i forgot to mention the USB 6259 I am using is the BNC terminated version. 

Would the SCC system still work if we make a cable that will bunddle up all the BNC terminals and connect them to a mass termination output?

Again, thank you for your help and time.

Regards,

Fernando 

[Andrew_B]

Hello fsouto,

In this case, the mass-terminated version of your USB 6259 is the only recommended option for using with a SCC system. I am not aware of any workarounds to this with M-Series USB devices. Part of this is I am not aware of any examples of the cable you are describing. I again reference the SCC page for the different options that are available for use with SCC systems.

Regards,

Andrew Brown 

[harifluxgen]

>> Another option you can consider is software filtering the signal using LabVIEW or SignalExpress. One example functions that would perform this purpose include the Filter Express VI.

Andrew, if I am not mistaken, antialiasing must be performed in hardware, as once aliasing occurs, the noise frequency is reduced to a digital frequency and cannot be distinguished from the signal frequencies in software.