Desktop Recorder

Discussion in 'Additional Libraries' started by Pachuquin, May 17, 2009.

  1. agraham

    agraham Expert Licensed User

    I'm afraid there is something wrong. :( If Ttransform = 2 then "3 Sines" transforms and inverses fine but "3 Cosines" does not retrurn the correct time series after the IFFT. I don't know where the problem lies. I thought that it worked fine on your previous version but unfortunately I can't check it as the latest version overwrote that previous version in my project folder and I can't download it again as you have removed it. Please can you have a look if you still have a previous version available?
  2. redbird

    redbird Member Licensed User

    Well, after a bit of playing around, I came to this user-interface with a moving needle, and without much effort, thanks to your code.
    I should be ready in a few days to post the final program, once I did some more testing. Your name ("Klaus") is in the credit list, if you don't mind. I would even put your real/complete name with pleasure, but that would be rather indiscrete to ask, I think. :)


    Attached Files:

  3. agraham

    agraham Expert Licensed User

    @Klaus - I found the error, it was a silly typo that was so obvious I couldn't see it at first :(

    EDIT :- It wasn't that. I'm presently totally baffled :confused:
    Last edited: Mar 24, 2010
  4. klaus

    klaus Expert Licensed User

    Hi Andrew,

    Unfortunately I don't have the previous versions either.

    I don't rember having seen this before.
    The CalcInvFFT function has not been changed in the FFTdemo program in the last versions.

    I had a closer look to undestand what happens.
    I modified the FFTdemo program to:
    - set the second half of the real and imaginary part in B4PPC
    - and calculate the InvFFT with FFT.Inverse

    When you run the test program it will show a single cosine.
    Click on FFT to show the first half of the FFT signals
    Click on CalcInvFFT we get what we see in the FFTdemo program
    Click on CFFT and FFT to calculate a new FFT with the inverse time signals with Transform1
    We see that
    sample 0 has a value of 2 instead of 0
    sample 256 has a value of -2 instead of 0.
    I don't know where these values do come from.

    Click on CSetFFT the program adds the second half of the FFT signal
    and sets DataReal(0)=2 and DataReal(256)=-2
    Click on C Inv FFT you see the same as what we get with the FFTdemo program.

    Then change lines 940 -943
    ' DataReal(0)=2
    ' DataReal(256)=-2

    Repeat the same as above, the inverse transform works.

    Best regards.
  5. mjcoon

    mjcoon Well-Known Member Licensed User

    Not sure what versions you want but I downloaded and still have FFT zips 1.1, 1.6 and 1.7...

  6. klaus

    klaus Expert Licensed User

    If you still have versions 1.6 and 1.7 of the demo programs could you please post them.
    If you mean the FFT library versions I have them all.

    Thank you and Best regards.
  7. mjcoon

    mjcoon Well-Known Member Licensed User

    No, sorry, I only have

  8. agraham

    agraham Expert Licensed User

    Well spotted Kalus:icon_clap:. "DataReal(n/2)=0" was the problem.

    When rebuilding the complex conjugate part I earlier said in post #56 "This leaves no value to be relected into index 256 so I have left it as zero." The implicit assumtion was that the data array was initialised to zero but as you are reusing the array there is an unwanted value in there. Fixed dll attached together with almost final help that incorporates your description of the demo which I have taken the liberty of slightly amending to more idiomatic English - hope you don't mind!

    I'm afraid that I only have the latest as the later ones overwrote the earlier ones.
    So do I, and all the sources. My version control system is pretty strict - at least for the stuff I generate myself!

    We are nearly there! A couple of comments about the demo.

    1) Why not make the "Calc Inv FFT" button visible at the beginning? Once it is visible it stays visible anyway.
    2) "Click on one of the sine buttons to continue" implies you can't click the cosines button! How about "signal buttons"?
    3) The "Inverse FFT Imaginary" graph legend is wrapped as the label is too short.
  9. klaus

    klaus Expert Licensed User

    Hi Andrew,
    I remembered this post, and as the CalcInvFFT routine in the FFTdemo program was not changed I was looking at the second half of the FFT samples.
    No problem, I'm glad that you do it.

    Your suggestions are included.

    Unfortunately in the file the FFT.cs file is missing.

    Attached the last FFTdemo program.

    Best regards.

    Attached Files:

  10. agraham

    agraham Expert Licensed User

    I didn't bother including it as I'll now post the library and other usual items in a release quality archive in a new thread, probably tomorrow.
  11. agraham

    agraham Expert Licensed User

    I see the built-in help still refers to "Remove f2,f3". Shall I remove it from the source or do you want to do a last check before I post it?
  12. klaus

    klaus Expert Licensed User

    Updated help in the program:
    Remove f2,f3 ... is available only with '3 sines' and 'FFT'.

    Best regards.

    EDIT: I also updated the Word help file for Remove f2,f3

    Attached Files:

    Last edited: Mar 24, 2010
  13. redbird

    redbird Member Licensed User

    Klaus and Agraham, my code is finally finished. The app is here, you'll easily recognise the fact that I used the fft library, and also Klaus his "moving needle" code in the menu Tools / Tachometer. I want to thank you again for all your help, and as I promised, both your names are mentioned in the credit list. Look at the help menu in the tachometer screen, at the bottom.
    The app will of course be of no use for you, as it is about R/C helis, but it seems to become rapidly popular between these hobbyists. The website had 500 unique visitors in a single day since I put the new version online yesterday. Have a peak or a download at HeliPort.
  14. agraham

    agraham Expert Licensed User

    Will that be one mountain or two? :) (peek)
  15. klaus

    klaus Expert Licensed User

    Hi redbird,

    I just had a look at the desktop version and tried it.
    Looks pretty nice.

    I mad some records, and luckily the wasching machine was running nearby, and I measured the speed of the drum during spinning !

    A few posts ago you asked me:
    I thought I had already answered you but it seems I didn't.
    It's not indisctete, my full name is Klaus CHRISTL, it can be found in the Abouts of my programs.

    I think you should also add a text over the spectrum button, it's not obvious to know the button's function. I would even set the 3 buttons, other than recording, to invisible during recording.

    Best regards.
  16. redbird

    redbird Member Licensed User


    It's done, your full name will be in the credit list in the next release.
    And I will make all buttons disappear while recording, and only show the spectrum buttion with the label when appropriate. Some finetuning now.
    I even let the user choose one of eight sounds to be played when the recording is finished. It's impossible to look to the screen when flying a R/C heli, believe me, these things are very unstable by nature.
    And maybe a kind of ini file to remember the user his choice, at a next start of the app.
    BTW, I'm happy for you that you were able to check your washing machine. :sign0142:
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