Jump to content

Signal processing


patleb

Recommended Posts

I have been using a Developers Suite for quite some time and have found some of the VI's in the signal processing tool kit very helpful. I am not involved in video processing at this point; lots of underwater acoustics. There are many VI's I have not used and there are limited examples in many cases. I have not found current resources that discuss DSP applications for most of the Vi's. What resorces are available?

Thanks.

pat

Link to post

If you are finding some of the built in signal processing tools lacking, I might suggest looking into MathScript (aka Matlab) nodes. Despite the work of NI, there is still a world of matlab signal processing code that is quite useful at times and this is a way to bring it into labview. (apologies if you were aware of this already)

Link to post

I have used many FFT, convolution, crosscorrelation... vis and have produced excelent results. Mainly I use a PXI 1045 with PXI 5412 AWG, PXI 5922 Digitizer with other modules including timing module. Since I work with signals below 1MHZ this system has been great.

However I have the feeling I am just scratching the surface using DSP tools in LabVIEW. There is much in the Time Frequency Analysis-Spectrogram-Feature Extraction-JTFA-Gabor transforms etc that I really have no experience with. I am looking for good information on using these tools. There are some helpful examples at the NI website and in LabVIEW but there is not enough informaton for me to get a grip on using these tools efficiently.

Link to post

It sounds more like you need to learn the DSP theory than about the VIs specifically. For whichever VIs you're interested in, use either the name of the VI or whatever documentation there is for it as a jumping off point for your Google searches. Yes, NI examples make it a lot easier, but sometimes you just have to learn the hard way. ;)

Link to post
  • 1 year later...

Any one with experience with cepstra and their interpretation, please help me understand this.  I calculated the auto spectum and the cepstrum of a square wave.  As expected, On the autospectrum, I got a strong component at the fundamental frequency (1 kHz, in my example) and the odd harmonics, whose amplitude decreasing nicely with the harmonic order.  On the cpstrum, I  was expecting events (or spikes, if plotted in absolute values) at the corresponding quefrencies of 1/1000, 1/3000, 1/5000, 1/7000, ... .  I am not getting this.  Please, give me your thoughts 

Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Similar Content

    • By cpipkin
      Hello,
      I am working on code that will read a waveform of a sound pressure measurement and calculate the octave band levels. I would be incredibly grateful if someone could take a glance at my code to see what I have wired incorrectly...
      The issue I think I'm having: The output of the "Basic Averaged DC-RMS" output wont index when I put it into the for loop. I tried to get around this problem by building arrays for each RMS output and then indexing into the for loop. Doing this doesn't allow me to graph the output... Any ideas as to why the "Basic Averaged DC-RMS" wont index directly?
       
      The code (inspired by new NXG example) is attached, both VI's must be downloaded in order to run the "Octave Band Levels" VI. Also, I'm aware that LV has a toolkit for sound analysis & octave band analysis... but I do not have access to this toolkit, which is why i'm trying to write my own VI. 
      Thanks in advance!
      Octave Band Levels.vi
      Waveform Butterworth Filter.vi

    • By cpipkin
      Hello
      I am trying to save TDMS files that ideally contain the following:
      - 3 xy graphs (each containing two 1d arrays)
      - 1 waveform
      The problem i'm running into is that when I convert the xy graphs to waveforms, the x-axis is converted to time, which isn't real or useful to me. I've attached screenshots of what the XY graph should look like VS what it ends up looking like with the waveform.
       
      How to I make sure the x-axis is preserved so that I can save to TDMS?
       
      Edit: VI is included & pictures have been updated to better represent my code.
       

       
       

      TDMS Waveform Example.vi
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.