"Re-Chunking" A labview waveform per iteration.

[xkenneth]

Hi,

  I've got a quick question, so say I've got a DAQ Block, that captures a signal at 300 Samples/Sec. So for every iteration of an outer while loop I get 300 Samples Per Second. Now I want to do some signal processing where, for example in a for loop inside the while loop, where I look at the samples for that second in chunks of X (we'll call it 10) samples per second. Is there some way to "Re-chunk" a waveform over iteration like this?

Regards,
Kenneth Miller

[jon_mcbee]

You probably don't want to have that for loop doing its re-chunking inside your DAQ while loop.  You could take your data out of the while loop using a queue and then re-chunk in a data processing loop.  Or if the re-chunking is not time critical you wait until all your DAQ is done and then re-chunk from file (or array in memory).  I dont know if that is helpful to you or not.

Cheers

[xkenneth]

That sounds fine, but how do I "re-chunk" it?

I'd rather not convert it to a ray of scalars, because then I'd have to keep track of the DT and timestamp manually, is there no VI that works on the waveform or DDT type?

Regards,
Kenneth Miller

[Kenneth.Miller]

Can someone please help me with this?

[Jared_B]

Kenneth,

You can convert the DDT to a Waveform data type.  Then you can get the waveform components, (t0, dt, and Y).  Depending on what signal analysis you are doing, you might not even need to do this.  But, then you can build the waveform with the values from the get waveform components, and re-construct a waveform back.

I guess it all depends on how you are 'de chunking' your data, and what type of data processing you are doing.