Lock in Amplifier on Single Board Rio 9636

[Slev1n]

Hey Guys,

I have to program a lock in amplifier for an analog signal i get from a microphone with a high SNR.

I have Labview 2012 SP1 and FPGA/RT 2012 and a SBRIO 9636.

I found an example: https://decibel.ni.com/content/docs/DOC-1762

LIA_IPnet_LabVIEW2009.zip

Now I am trying to understand the mostly uncommented code.

Question 1:

Can I use this program with my SBRIO? I prefer this to the SBRIO version on the same page because it is a dual phase LIA.

Question 2:

I added my own zip file were I added some comment boxes (orange background) but I commented in german. Maybe you can tell me if I am right so far. (Mainly in the HostLIA.vi and FPGA_LIA.vi)

Question 3:

Can someone help me to understand the subvi on the FPGA named "costa loop"? For example: What exactly is the code doing in the VCO subvi?

Question 4:

Can someone give me a link to a good document/website which explains the mathematic details of the decimation in a LIA?

(german or english)

If someone has another good working lock in program, please tell me.

Thanks for your help

Stefan

[Elli]

Hello Slev1n,

here is some documentation about the Lock in Amplifier (mathematically):

http://www.thinksrs.com/downloads/PDFs/ApplicationNotes/AboutLIAs.pdf

in general it is possible to configure a cRIO project to a sbRIO project. You just need to configure a new target.

Regards, Elli