07-09-2008 10:38 AM - edited 07-09-2008 10:45 AM
07-14-2008 03:39 PM
Hello friend,
I analyzed your case and I suggest you to test it using mathscrip in LabVIEW. There are two possibilities to do it. The first is using LabVIEW MathScript, like is described in these two pages below.
http://zone.ni.com/devzone/cda/tut/p/id/3502
http://zone.ni.com/devzone/cda/tut/p/id/3257
Other possibility is use the VI “MATLAB scrip” that is located in Mathematics -> Script & Formulas -> Script Node -> MATLAB scrip, searching in block diagram’s tools pallet. Or use MathScript Node located in Mathematics -> Script & Formulas -> MathScript Node. There are some examples in LabVIEW help.
There are many possibilities to explain why this difference can be occurring. Are you sure that your program is correct in LabVIEW and in Matlab? Are they really doing the same thing? I verified in Specgram.txt (that you sent us) you are using a parameter pi, but this parameter is not present in your program in LabVIEW. Is this parameter is really present in your program? Is this parameter is really correct? The Marhworks page shows this parameter called A like a vector (http://www.mathworks.com/access/helpdesk_r13/help/toolbox/signal/specgram.html).
Do you know what is the B output unit used by Matlab? The output magnitude unit used by LabVIEW is Vrms²/Hz.
Please, check these comments above.
Best regards.
Bruno M.
07-25-2008 01:22 AM