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acquire a signal with two differents rates

There is an Express VI called Align and Resample.  Sample at the higher rate and use that to get the "other" rate.

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Message 11 of 24
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@Roro8989 wrote:

OK but I have only 1 channel and I would like to record this channel with two differents rate in the same time. I haven t multiple channel, just one.

Thank you very much

 

Romaric GIBERT


Then you really should have mentioned that you were using the other 3 channels of the board for something else. The decimate function or Express VI that Ravens Fan mentioned are your options.

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Message 12 of 24
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@Roro8989 wrote:

OK but I have only 1 channel and I would like to record this channel with two differents rate in the same time. I haven t multiple channel, just one.

Thank you very much

 

Romaric GIBERT


ONE channel means ONE rate at a time.  It's like you're asking how to drive one car at two different speeds simultaneously.  Smiley Surprised  Obviously , it can't be done.

LabVIEW Pro Dev & Measurement Studio Pro (VS Pro) 2019 - Unfortunately now moving back to C#, .NET, Python due to forced change to subscription model by NI. 8^{
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Message 13 of 24
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If this wonder board allows different rates on different input channels at the same time... wire the input signal to two channels and set up a seperate acq rate for each task.

 

Ben

Retired Senior Automation Systems Architect with Data Science Automation LabVIEW Champion Knight of NI and Prepper LinkedIn Profile YouTube Channel
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Message 14 of 24
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ok thank you very much everybody. I ve tried the align and resample but  I don t see any change. I would like to know how I can configure my express. For example if my high rate is equal to 20kHz and I want to resample this signal at 5kHz, What setting can i change for this? the dt ( and if it s yes what value)

thank you very much

 

Romaric GIBERT

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Message 15 of 24
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Simple arithmetic. The dt for 5kHz is the reciprocal of it - 1/5000 = .0002

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Message 16 of 24
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I will make some suggestions if I get your problem right.

 

I would firstly get the dynamic data and turn into waveform and record it.

 

You can use the same signal resample by using "Build Waveform" by changing "dt" value.

 

Here is a sample.

 

asd.png

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Message 17 of 24
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"... and this amp goes all the way up to 11 !" (Spinal Tap, the movie)

 

 

Ben

Retired Senior Automation Systems Architect with Data Science Automation LabVIEW Champion Knight of NI and Prepper LinkedIn Profile YouTube Channel
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Message 18 of 24
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@Motorbreath wrote:

I will make some suggestions if I get your problem right.

 

I would firstly get the dynamic data and turn into waveform and record it.

 

You can use the same signal resample by using "Build Waveform" by changing "dt" value.

 

Here is a sample.

 

asd.png


Not at all the same thing. A decimate or resample will reduce the number of samples, which is what I think the op wants. Just changing the dt will not reduce the sample size.

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Message 19 of 24
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Sorry but I don t know what is the good solution, the solution with the VI Align and Resample or the solution has given Motorbeath? thank you very much

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Message 20 of 24
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