Realtime fft

Hi
is it possible to do a "realtime"-fft on LV6? I mean, to do a data acquisition (not a sinus-function, just normal sensor data) and see the fft-spectrum and the frequencies and the different modes.
is there an example somewhere.
thanks for your help.
yves

There's lot of examples. Just go to Help>Find Examples>Analyzing and Processing Signals>FFT and Frequency Analysis. There's one called Simple Spectrum Analyzer.vi that's written for use with a daq board. I won't get into a discussion of "realtime" but it does do a continuous power spectrum.

Similar Messages

  • Can not copy data within a realtime cube due to combination issues

    Hello all,
    I want to use a planning function on a realtime cube in order to copy data from from Co_area CO1 into Co_Area CO2. The Co_Are and the profit center are part of the realtime cube, but not the nav attribute of the profit center.
    When I test/run the planning function via a sequence in planning modeller I get an error message: The combination 'CO2/PCxy,#' is not valid, valid is 'CO2/PCxy,abcd': characteristic '0PROFIT_CTR' .
    Has this error something to do with the relationship of the master data of profit center and its nav attributes?
    Any help would be great.
    Best regards,
    Stefan form Munich/Germany

    I guess this problem is coming because of some wrong combination of records present in cube for controlling area 1. Make the below changes in the planning function. Dont include profit center in the level. Just include controlling area. Create a characteristic relationship of type derivation by master data attributes. Give source char as Controlling area and target as profit center. This will mantain consistency of char. combinations b/w controlling area and profit center in cube for the newly generated records.

  • MyRIO FPGA FFT Express VI timing analysis for multiple input mode - trying to perform fft's on a 3-axis accelerometer

    Hi Everyone!
    Project Background:
    I've been working with the myRIO FPGA in an attempt to generate an application capable of sampling a tri-axis accelerometer and performing an fft on each axis. I've successfully developed an application for a single axis, but attempting to duplicate the code to sample the second and third axes in parallel results in an estimated 150% resource utilization for the tiny FPGA's LUT's. Additionally, I'm looking to avoid sequentially processing each accelerometer input using triggers and a single fft block because that reduces my fft update frequency significantly (e.g. I can't calculate another fft for input 1 until I calculate an fft for inputs 2 and 3).
    After reading up on the fft vi, I'm thinking that I can use the M-interval input indexes / Continuous output indexes Input/Output Index Pattern mode. My thought is that I can edit the vi to remove any math that "recombines" these three vectors into a single fft, resulting in 3 separate fft's. I'm also hoping that this process requires less time than using the sequential method described above. 
    The Questions:
    1. Has anyone done an fft on three inputs using the myRIO at sampling rates > 20kHz and fft sizes of 1024 or larger? If so, I may just be lacking some proper resource management.
    2. Does anyone know where to find timing information on the M-interval input indexes / Continuous output indexes Input/Output Index Pattern mode? The manual only provides timing diagrams for singel channel / single input modes. I don't want to waste my time modifying the vi if it will still take 3x as long (assuming modifying the vi is even a possibility).
    Further Information:
    I already have an application written that samples the accelerometers at >20kHz and then performs the fft on the main processor, but now I'm looking to see if it is possible to perform all signal processing on the FPGA side. The processor performs decently enough, but the timing is not as consistent as I would like it to be. Lastly, I am aware that the myRIO itself has a built in accelerometer, but I need to mount the accelerometer in an environment where the myRIO would probably be damaged and definitely cannot fit.
    Any thoughts are much appreciated! The excessive FPGA compile times for this thing make the old guess and check method less appealing.
    -Chris 

    Hi Chris,
    Thanks for posting and the detailed background on the project! To answer some of your questions:
    1. The FFT Express VI does use a significant amount of space. The FPGA on the myRIO is somewhat limited space-wise. Your best option may to implement the FFT for 1 channel on the FPGA and the other two on the RT side.
    2. I converted the FFT Express VI to a subVI and I am not sure if you can trim too much code from it. The subVI is also very complex so re-working it would be a significant amount of work. I could not find much documentation on M-interval input indexes / Continuous output indexes Input/Output Index Pattern mode timing. 
    I hope that this helps!
    Thanks,
    Frank
    Application Engineer
    National Instruments

  • How to have a live feed from application server log file (realtime viewr )

    how to have a live feed from application server log file (realtime viewr for apps log files)
    hi , thank you for reading my post.
    is there any way to have a live feed of Application server log ?
    for example is there any application that can watch the log file and show the changes as new log items come in ?
    can some one with more experience help ?

    Your question would be more suited to the Developer Forums
    http://devforums.apple.com
    but anyway...
    My goal is to develop a web application that is able to run on iPhone too, to capture the audio and video content from its camera and mic.
    Web Apps running in Safari don't have access to the camera or mic hardware.
    Or I should built a native application distributed through Apple store?
    That is your only option, although such a system already exists:
    http://itunes.apple.com/us/app/ustream-live-broadcaster/id319362690?mt=8

  • Integrated Planning - trying to load data from basic to realtime cube

    I have created a mulitprovider for my basic and realtime cube, and trying to copy data from basic to realtime using standard copy function in IP. It is not erroring out but data is not getting copied either. Both cubes having exactly the same structure. I can do a export datasource or a BPS multiplanning area..but I need a solution in IP..Any help would be appreciated...Thanks much..

    Infoprovider --> Multiprovider
    Agg Level --> Selected fields need to be copied
    Filter --> None selected, wanted to copy as is
    Pl. Fnc --> Standard Copy.
                    char usage: Selected infoprovider for 'changed'
                    to parameters: selected all key figs ( percent and amount)
                    from and to values: Basic to realtime
    Let me know.

  • How do I perform an FFT or ReFFT in VB6 using measurement studio

    I am trying to make a filter by taking a 1D array of voltages and doing a ReFFT() and padding the high frequencies in the array with a value of zero and then going back to time domain with ReInvFFT().  Here is my code which does not seem to be filtering any high frequency content.
    lngReturn = frmMain.CWAI1.AcquireData(varData, varBinaryCodes)
    frmMain.CWDSP1.ReFFT varData, realdata, imgdata
    For i = (UBound(realdata) / 100) To UBound(realdata)
        realdata(i) = 0
        imgdata(i) = 0
    Next
    frmMain.CWDSP1.ReInvFFT realdata, imgdata, varData
    After the function is done varData has a 1D array of filtered real voltage values.  It does not seem to be filtering and I get back exactly what I pass in.  I know it must be something simple that I am missing perhaps the variable cannot be used to pass in and then  back out the values??
    Please shed some light as there are NO examples of this use of FFT.
    Thanks

    Arthur,
    Thank you for your reply.  But at this point, one of my points of confusion is what software I have available to me.  I wish I had a useful central help desk to call up and just say, "Hey, load me up with all of the professional version(s) of Visual
    Studio.  But I do not know what we have license to.  And I kind of need to know what the options are, so that I can ask a specific question of our vast buracracy.
    For now, I have downloaded only free versions of Visual Studio client software.  Since my company does have servers running Microsoft SQL Server, I am going to assume that we have proper licensing for those servers.  But does that server license
    allow me to get any professional versions of the PC client software for the various Visual Studio(s) 2012?
    And if I get a professional version of Visual Studio 2012, does that do away with the three different flavors that I have right now?  I have 2012 versions of SQL Server Management Studio, Visual Studio Express, and Visual Studio Shell (Integrated).
    Your feedback is much appreciated.
    Thanks!

  • How to push realtime data from SQL Server

    Hello,
    I am looking for the best way to approach the following
    situation ... 1) how to connect 2) what I will need to maintain
    "realtime" updated data on the the web browser (client) side 3) and
    if Flash Media Server 2 or the Flash runtime (Platform) would be
    required.
    I have a SQL Server database that is updated every 5 seconds
    with new data and I need to have this data reflected on a Flash
    webpage. For simplicity, lets just say its a table that contains 50
    records with 4 fields. When/if the data changes in any of the
    fields it needs to show up "realtime" on the webpage. All thoughts
    would be helpful ... but unfortunately it must be done in Flash
    (don't ask) ... Thanks in advance!

    Having a webpage designed using FLASH 8 that can
    communicate with a SQL Database would be something I am looking
    into also. I hope someone that really knows what he is doing
    explains this to us. I would like to use this with a catalog that
    would be updated when I update the SQL Data. Why use FLASH? Reason
    I am using it is that one has control of their work. The typical
    HTML and other programming that works with HTML seem to NOT have a
    standard making your website work look really good in one browser
    but look like heck in another and some browsers will just not work
    like you designed it.

  • How to schedule a background job in realtime

    Hi,
    Can you tell me how to schedule a background job in realtime.
    give some example scenerios in scheduling the background jobs in realtime.
    Thanks.
    sam.

    And also.....
    There are two ways for you to handle,
    one manually setting up the job through SM36 which is better and convinient,
    secondly through program using FM's JOB_OPEN, SUBMIT, JOB_CLOSE.
    Find below steps in doing both:
    Procedure 1:
    1. Goto Trans -> SM36
    2. Define a job with the program and variant if any
    3. Click on start condition in application tool bar
    4. In the pop-up window, click on Date/Time
    5. Below you can see a check box "Periodic Job"
    6. Next click on Period Values
    7. Select "Other Period"
    8. Now give '15' for Minutes
    9. Save the job
    Procedure 2 via Program:
    Below is a sample code for the same. Note the ZTEMP2 is the program i am scheduling with 15mins frequency.
    DATA: P_JOBCNT LIKE TBTCJOB-JOBCOUNT,
    L_RELEASE(1) TYPE c.
    CALL FUNCTION 'JOB_OPEN'
    EXPORTING
    JOBNAME = 'ZTEMP2'
    IMPORTING
    JOBCOUNT = P_JOBCNT
    EXCEPTIONS
    CANT_CREATE_JOB = 1
    INVALID_JOB_DATA = 2
    JOBNAME_MISSING = 3
    OTHERS = 4.
    IF SY-SUBRC 0.
    MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
    WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
    ENDIF.
    SUBMIT ZTEMP2 VIA JOB 'ZTEMP2' NUMBER P_JOBCNT
    TO SAP-SPOOL WITHOUT SPOOL DYNPRO
    WITH DESTINATION = 'HPMISPRT'
    WITH IMMEDIATELY = SPACE
    WITH KEEP_IN_SPOOL = 'X' AND RETURN.
    CALL FUNCTION 'JOB_CLOSE'
    EXPORTING
    JOBCOUNT = P_JOBCNT
    JOBNAME = 'ZTEMP2'
    STRTIMMED = 'X'
    PRDMINS = 15
    IMPORTING
    JOB_WAS_RELEASED = L_RELEASE
    EXCEPTIONS
    CANT_START_IMMEDIATE = 1
    INVALID_STARTDATE = 2
    JOBNAME_MISSING = 3
    JOB_CLOSE_FAILED = 4
    JOB_NOSTEPS = 5
    JOB_NOTEX = 6
    LOCK_FAILED = 7
    INVALID_TARGET = 8
    OTHERS = 9.
    IF SY-SUBRC 0.
    MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
    WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
    ENDIF.
    Hope the above helps you.
    ***********reward points,if found useful

  • How can i display the signal out of a FFT block to a graph?

    What conversion is required in order to convert a the output of a FFT block to a waveform display? The signal input to the FFT block is a binary pattern signal!

    Hello St Augustine,
    Unfortunately, I cannot open these files that you have attached so I cannot tell you for certain where your problem lies. However, if you are using one of the FFT VIs from the Analzye>Waveform Measurements sub-palette, then you should be able to wire directly from the VI to a Waveform Graph. Make sure you are trying to wire to a Wavform Graph not a Waveform Chart. If you are using the FFT VIs on the Analyze>Signa Processing>Frequency Domain sub-palette, you should also be able to directly wire into a Waveform Graph, but please refer to the KnowledgeBase document linked below for more information about plotting complex numbers.
    http://digital.ni.com/public.nsf/websearch/C010A823CEA80D5386256938005A066E?OpenDocument
    Rega
    rds,
    Jyoti F
    National Instruments

  • FCP clip time remapping / speed ramping question re realtime after changes?

    Hello All,
    My first post here! I tried searches for this topic but didn't find....
    I wasted hours today messing with the keyframe editor to try and ramp parts of a single clip... first time using this feature and couldn't follow the manual! way too difficult to grasp without fluency in 'techygeekconfusic' lingo. Anyway, I don't think the topic was covered from what I read in my version of the manual.
    So I went straight for the keyframe editor graphic display under the clip in timeframe and put in a few points with the pen tool (using time graph blue line) and seemed to be going great until I realised that the segments in the single clip (ten minutes long) that I was adjusting were affecting what came after - ie slowing down the remainder of the clip. And that was all I could get from my manual that this happened without any explanation about stopping it happen by letting the outpoint of the clip readjust automatically for the changes made to that part of clip so that altered clip would be shorter in timeline...
    I then tried again from the start but noting the minus time on pentool arrow when I slid each keyframe point back and subtracting it from the duration in motion tab and that seemed to work for a while...
    but God bless my little brain! what I really wanted to happen - for the blasted thing to readjust itself automatically after I had adjusted a segment of the clip so that the remaining non-adjusted part would play in realtime with a new shorter outpoint in the sequence timeline - just couldn't be realised in my little brain or in the 'user friendly' control panels of FCP.
    I tried to get hold of the 'bezier' point at the end of clip and drag forward at the same rate as each change but could'nt get hold of it! I tried to put two points with pen tool at same time but couldn't isolate them from one another to create four points for adjustment without having still frames between.. blah blah.. I tried to get snapping to the pen tool points for further control but couldn't... duh!
    Please! how do you do it! obviously I have limited intelligence but I need to do this now. I want to adjust the 10 minute clip (DVCproHD 720p24N format - not that this should matter as my sequence settings are same) adjust the clip at maybe 10 different places so that it ramps in speed to cover up some boring areas and then back to normal speed after the changes - not back to some slo mo **! speed.
    I tried cutting with the razor tool to isolate and that didn't work either and other analogue brain type stuff ok I know you are laughing at me now but please help?!! I'm pretty new to this stuff, give me the old reliable Steenbeck and a few real bins and strips of film hanging on clothes pegs and I'll be ok...
    Help will be most gratefully appreciated!!!!!!!!
    Barra
    Message was edited by: BarraAppleId

    Andy did a very good job explaining the underlying problem with the time remap tool.
    The key thing to remember is the first and last frame are fixed in time. If you speed up the clip, time after that keyframe will have to slow down to compensate. Imagine the clip is a rubber band that has been cut so that it is a long string-like form. Now imagine anchoring each end of it with a push pin to a board. If you grab a point on the band and pull it toward one of the pins, the part of the band on the side you are pulling away from the anchor will stretch (run slower) and the side you are pulling toward will bunch up (run faster). But, when all is done, the start and end will still be at the fixed points.
    The way I've worked through this is to make a general guesstimate of how long the clip will be once all the ramping is complete. For example, I want the clip to start at normal (100%) speed and ramp up to 300% and back down to 100%. I might start with a clip having a constant speed of 200% and then change it to variable and play with it. The key concept is if you can get the overall LENGTH to where it should be, the rest works out fine.
    I have repeatedly asked in the FEEDBACK/New Features page that they add a toggle to the speed/time remap tools. This toggle should allow you decide whether the playback TIME for the clip should be fixed or flexible.
    For example, if you were working with a 4 second clip and wish to slow it down by 50% -
    If 'Maintain Time' is toggled ON, when you decrease the speed of clip by 50% - the clip will still play for 4 sec (but will show only half the total frames).
    If the toggle is OFF, the 4 sec clip will now play for 8 sec and will display all the frames.
    Where this concept becomes really powerful is when it's applied to time remap. If you have 'Maintain time' toggled OFF, as you adjust speed, the end point of the clip will float in time. If you increase the speed, the overall time of the clip will shrink. If you slow it down, the end point moves out in time.
    We need to keep asking ...
    x

  • How can I use the Diadem FFT Analysis GUI to give me multiple outputs given multiple inputs?

    I have a few hundred channels I would like to perform FFT analysis on. They are mostly of different lengths, but I know I will have groups of 7 that will have the same number of data points. The default GUI will accept those 7 sets since they are the same size, but it will only give me one output as a combination of the sets. Is there a way to get Diadem to give me an FFT output for each set without having to select each data set individually?

    The way it worked with the default channels, I had to make sure I wasn't going crazy because the way you demonstrated worked very well for me. That being said, for some reason what I am doing does not work. I've recently found that it is in changing the details in the GUI that makes my output different than yours. The differences are as follows:
    1) I do not use a time channel. That is always left blank.
    2) in the 'Window Functions' tab, I change the window type to Hanning
    3) In the 'FFT Functions' tab, only amplitude is checked with the properties 'Peak amplitude', No Third/Octave, and Average amplitude is changed to arithmatic.
    4) In the 'Time Intervals' tab 'Length/Start/Overlap' is checked, Interval length is changed to 1024, and overlap (%) is changed to 50.
    I've also found that changing any number of these details from the default will cause my proplem to crop up. I am fairly sure that most of those options are just as feasibly done to one channel as they are to multiple. Is this a bug, or am I misunderstanding a property of FFT that has gone over my head? Please try changing a few of those properties since it seems like it should work just as well for all the channels as it does for just one, but that doesn't seem to be the case.
    Another point of confusion is that while the window previewing the inputs in the GUI will show all the inputs I have selected, the window previewing outputs only appears to preview a single unknown output. That is just a side note though.

  • How can I see what I'm shooting with my Iphone in realtime on my Ipad

    Hi Everyone,
    In a few days time, I need to make a short film with an iphone.
    And in order to make things easier, I would like to connect my Iphone to my Ipad, preferably via BLUETOOTH ('cause I'll be shooting on the streets where there is no WIFI and my to have my Iphone function as a camera and a WIFI hotspot doesn't seem like a really good idea).
    So basically I'm trying to figure out how to connect my Iphone and Ipad to each other via bluetooth
    which
    allows me to see what my camera is filming on my iphone in realtime (or with a little delay) on my ipad.
    The Ipad kind of has to function as a second screen/ mirror screen/ remote monitor...
    So, if anybody has any suggestions on how to fix that? Or is aware of an App that does exactly that, which is out there, than I would love to hear all about it...
    Thanks in advance !

    There is no way to do what you want to so. No such app exists and there is no way to connect the two devices via Bluetooth for the purpose that you want.

  • FFT Frequency Resolution vs. Graph Update Rate of a Vibration Signal

    Hello,
    First, what I know:
    The frequency resolution (Hz) of an fft is 1/acquisitionTime (e.g. if 2 seconds of data are acquired, the frequency resolution is 1/2s = 0.5Hz).
    What I'm Wondering:
    Let's say I'm displaying an acquired signal on a graph and freq res = 0.5Hz.  The graph update rate is therefore approx 2sec.  This may appear to be an application with a problem from a user's perspective.
    Can I increase the update rate?
    It seems that with vibration data (i.e. mostly non-periodic) I could create a buffer that is 2sec long.  The first data acquisition sequence will fil the buffer with 2sec of data.  Then I could just acquire something shorter than 2sec of data (let's say 1/4sec).  If I am acquiring data continuously and I push the 1/4sec of data into the front of my buffer then perform the fft again, I have effectively increased my graph update rate to 1/4sec and my users think I'm great.
    Can anyone shed any light on whether or not (why/why not) this will work?
    Thanks for your time,
    Chris  

    The best tool NI provides for your application is the Zoom FFT.  This allows you to specify the span (frequency range of the FFT) and the zoom (the delta f such as 0.5hz) in the FFT.  The Zoom FFT has a built in buffer, called overlap and allows you to set the overlap so that it updates at the appropriate rate, event though you may need many seconds of data to get the delta-f in the FFT you are looking for.  We package all this and manage units to display the correct units for power density, power, linear, magnitude, rms, 0 to peak, peak to peak, etc.  We even provide a express VI for the zoom FFT and it is also part of the Sound and Vibration Assistant, requiring no programming at all.
    http://digital.ni.com/public.nsf/allkb/F70DB3441DC5AB9986256E97005BA825
    http://zone.ni.com/devzone/cda/tut/p/id/6107
    http://zone.ni.com/devzone/cda/epd/p/id/5505
    http://sine.ni.com/nips/cds/view/p/lang/en/nid/12152
    Preston Johnson
    Principal Sales Engineer
    Condition Monitoring Systems
    Vibration Analyst III - www.vibinst.org, www.mobiusinstitute.com
    National Instruments
    [email protected]
    www.ni.com/mcm
    www.ni.com/soundandvibration
    www.ni.com/biganalogdata
    512-683-5444

  • How do I get my DAQ to have frequency resolution of 0.5 hz after FFT ?

    Hi all,
    I was just wondering how do I get a frequency resolution of 0.5hz after the FFT from this VI.
    Or perhaps there can be some advice on where I must improve it.
    Appreciate all advice, thanks!
    -How81
    as of now, the waveform graph i obtained, I wanted it to be of 0.5 hz, hence I used its property to set it at 0.5hz.
    Message Edited by How81 on 10-13-2007 03:31 AM
    Attachments:
    Final DAQ.vi ‏107 KB

    Hi How81,
       I won't comment on your code, I'm unable to see it (I have LV 71.1).  So I'll discuss a little bit the DSP.
       If you want such a low frequency resolution, you have to sample a little longer.  If your top-frequency is 25 Hz, I don't see the need for sampling at 1 kS/s, that gives a Nyquist freq. of 500 Hz!!! You'll only have a large amount of data, not of your interest!
       Another good advice, is to sample for a long time.  To have a REAL resolution of 0.5 Hz, It is not sufficient to sample 2 MSample for one microsecond! So, you have to sample at least for 2 seconds, but I strongly suggest to sample for a longer time.  In DSP,you almost always have to use some tolerances.
       Another matter is FFT resolution due to number of samples. If you sample 2 kS/s for 1 second, and you'll get a "2000 point FFT (...)", you'll see 1000 equally spaced frequency samples, from 0 to 1000 Hz (ie 1 Hz spacing), you can't have a resolution of more than 1 Hz. I would suggest something like sampling at (say for tolerance) 100 S/s, (top freq. you seee in FFT: 50 Hz), for 10 seconds: so you have 1000 points, but you have a resolution of 0.1 Hz.
       A part from this, always consider that FFT works in 2-powers, so it's better to do a 1024 points FFT.   Then you can use zero padding techniques to "adjust" fft to see samples at right frequencies, or sample 1024*10 samples in time at 1024 S/s and then decimate..... you have many choices.
       Hope this can help. Have a nice day!
    graziano

  • How to do FFT of vibrations signal?

    Hello,
    I'm trying to measure the time and frequency spectrum of a vibrations signal.
    My time plot seems to be ok, but my FFT graph doesn't look right.
    An expected vibration FFT graph of a bearing should look like peaks at various frequencies, but my FFT graph looks only like a linear line.
    Does anyone know what's wrong with my attached program?
    Thank you.
    Y.Yang
    Attachments:
    3 axis white and green sensors v2.vi ‏122 KB

    Your code looks fine.  I double checked how you're acquiring data, and it seems fine.  I'm pretty sure that you are acquiring an FFT and the graph is just not scaled correctly.  Do the following:
    Right Click Waveform Graph 2 >> X Scale >> AutoScale X
    Right Click Waveform Graph 2 >> Y Scale >> AutoScale Y
    I've also attached an example of what I've done to get the FFT from a simulated signal.
    Che T.
    Applications Engineer
    National Instruments
    Attachments:
    FFT.vi ‏67 KB
    fft.png ‏43 KB

Maybe you are looking for