multirate FIR coefficients

[BeanBoy]

I am trying to port matlab filtering tools to labview and I need some help understanding the filter tools.

Creating a multirate FIR with labview I would like to use a set of predefined coefficients so that they match what I built in matlab exactly.

It appears that labview VIs create the coefficients based on the input. Is there a way to specify the coefficients?

The task seems simple enough on its face. I have a 22 bit adc, sampling at 30 KHz. We need to calculate rms counts at 100Hz. To do this the designers required the measurements made by the adc at its raw 30 KHz be filtered and decimated to 100Hz with a duration of 60s.

I don't have a license of matlab to use with the matlab module in the labview developer suite.

I am currently calling octave via the command call. Octave is able to run the matlab files. But the start time to make and command call is quite high (10seconds) for each instance. Then there is still the overhead of octave. This is too long for my purposes.

Any help on this would be appreciated.

[[dk]]

What digital filter VIs are you using to create the multirate FIR?

[BeanBoy]

I tried using the FIR Filter.vi with co-effiecents calculated in matlab and the results were not what I expected.

I tried using the same variables to build FIR Narrowband Coefficients VI. it produced different coeffiecents which can be expected. But it was 20 coefficents instead of 165.

fir1Sps.txt was from matlab.

So I am abondoning making the FIR filter coeffiecents in labview.

I will try again to use the FIR Filter.vi

Does the FIR Filter.vi remove the first N values from X. Where N is the  number of co-effiecents.

What format does FIR Filter.vi expect the co-effeicents in? 

[[dk]]

Sorry I was not able to respond as quickly as I wish I could have. But it looks like your question was answered in another forum post:

http://forums.ni.com/t5/LabVIEW/Decimating-for-novice-help/m-p/2405624#M744180

If you do still have any questions on the FIR Filter.vi please just let me know!