Finding the mean of a series of complex numbes to generate an avergage FFT spectrum

Hi All
I have a a 2d array of complex numbers. In fact I have a 10 x 133210 array that represents the complex result of a series of ffts taken from the time series of 10 mics.
For example
Frequency ::::::                 1Hz     2 Hz   3Hz   4Hz   5Hz      ad infinitum(!)
Amplitude for Mic 1             2+2i    2+2i   2+2i  7+2i  2+2i
Amplitude for Mic 2             3+2i    5+2i   2+2i  2+2i  2+2i
Amplitude for Mic 3             4+2i    2+2i   2+2i  8+2i  2+2i
up to Mic 10
Now i want to be able to average these spectrums so that I can regenerate the time series that would be found (or heard) if the listener was to perceive all 10 mics timeseries at the ear without the phase cancellation effects of the time domain.
So I take all 10 mics complex FFTs and I average across every column. I do this by summing all ten mics complex bin values and diving by 10 + 0i.
The result I get is very close to what I would expect in the frequency domain. I would imagine that if i was to take all ten signals with the same time series what is rengenerated in the frequency and time domain would be the same...
However the iFFT returns NaN
There must be a problem with my averaging process - can anyone shed any light?
Thanks
Greg

Greg,
1. The phase effects due to the spacing of the microphones is already in the data.  Unless you have a point source, it will be very difficult to sort out which components came from where.
2. Are there any NaN values in your array of means?
Can you post a small subset of the data (10 x 1000 rather than 10 x 133210) and your VI so we can see what is going on?
Lynn 

Similar Messages

  • To find the mean of a waveform

    Hi Everyone,
    I'm facing problem in finding the mean of a waveform. I'm acquiring two waveforms voltage & current, multiplying those two waveforms & want to find the mean of that resulting waveform. the answer what i am getting is much larger than what i get when i multiply two waveforms in Oscilloscope & calculate the mean from the scope itself. I'm unable to understand why there is such a big difference in mean values.
    Thanks in advance

    With issues such as this it is best to look at a small sample set of data and compare the two results. Could you post maybe a text file with your data and the results from your scope so I(we) could test it in LV and see what the issue is?
    -Brett

  • Finding the next smaller and next larger prime number

    Hey all, will this code help me find the next larger and next smaller prime number? I only ask because my main() isnt outputting anything, but everything looks fine there. So assuming I may have done something that didnt make sense here.
              //returns the next larger prime number
              long largerGetter = num;
              long lG = num + 1;
              while(largerGetter != 1)
                   largerGetter = PrimeChecker.primeOrNot(lG);
                   lG++;
              nextLargerPrimeNumber = lG;
              //returns next smaller prime
              long smallerGetter = num;
              long sG = num - 1;
              while(smallerGetter != 1)
                   smallerGetter = PrimeChecker.primeOrNot(sG);
                   sG--;
              nextSmallerPrimeNumber = sG;

    JimmyV88 wrote:
    Hey all, will this code help me find the next larger and next smaller prime number? ...If this isn't homework (which it probably is), use the BigInteger class to find a [next probable prime|http://java.sun.com/j2se/1.5.0/docs/api/java/math/BigInteger.html#nextProbablePrime()] given a prime number or keep subtracting two from that given prime and check if that number is [(probable) prime|http://java.sun.com/j2se/1.5.0/docs/api/java/math/BigInteger.html#isProbablePrime(int)] to find the previous prime.

  • How can i find the location of my ipod by serial number

    how can i find the location of my ipod by serial number. Someone stole my ipod touch and I cant find it. I have the serial number.

    No, the SN will only help identify the iPod as yours IF it is recovered
    - If you previously turned on FIndMyiPod on the iPod in Settings>iCloud and wifi is on and connected go to iCloud: Find My iPhone, sign in and go to FIndMyiPhone. If the iPod has been restored it will never show up.
    iCloud: Find My iPhone
    - You can also wipe/erase the iPod and have the iPod play a sound via iCloud.
    and go to FIndMyiPhone. If the iPod has been restored it will never show up.
    iCloud: Find My iPhone
    - You can also wipe/erase the iPod and have the iPod play a sound via iCloud.
    - If not shown, then you will have to use the old fashioned way, like if you lost a wallet or purse.
    - Change the passwords for all accounts used on the iPod and report to police
    - There is no way to prevent someone from restoring the iPod (it erases it) using it unless you had iOS 7 on the device. With iOS 7, one has to enter the Apple ID and password to restore the device.
    - Apple will do nothing without a court order                                                        
    Reporting a lost or stolen Apple product                                               
    - iOS: How to find the serial number, IMEI, MEID, CDN, and ICCID number

  • How to find the compoment version information given a PPMS number?

    Hi,
    <b>Problem</b>:
    I want to find the component version information with a PPMS number; and would like to know how to.
    (I don't know which forum is exactly proper to post this thread, and then put it in NetWeaver Platform category.)
    <b>Details</b>:
    In ERP system, transaction BOPP (PPMS work center), you can find product/component (version) information, including their PPMS number.
    While I didn't find the way to retrieve the component version and other information, given a PPMS number.
    Is this possible in BOPP? Or there is other ways to do this?
    Thanks and regards,
    Said

    user651567 wrote:
    Hi,
    Through putty we can access the unix server which is the Databse server.So i need the ip and port number to connect.Why don't you just walk down the hall and ask your friendly SA? Or if he's not in the same building, pick up the phone.
    I'm increasingly aware of a sub-culture that is afraid or unwilling to actually talk to their co-workers to find out information that is unique to their organization ....

  • K mean:: how to find the clustred data;:: or how to assign number t0 each group of data

    hi member
    i have download the LabVIEW Machine Learning Toolkit https://decibel.ni.com/content/docs/DOC-19328
    i want to excute the K mean algorithem to cluster the image in two group or three or more
    the problem is how to find the result i mean the clustred image', the image that contain 2 or three intesity value only
    or how to aasign a 1 vlaue to all intesity that 
    belong to cluster one and 255 to data that belong to cluster 2
    so that the image look like binary image???
    a my vi below
    best regards
    Solved!
    Go to Solution.
    Attachments:
    k mean.vi ‏12 KB

    my post before showed how to set the threshold manually using the graph's cursor.
    here's the automated k-means version, using the toolkit's .vi
    Alex
    ♜♖ LabView 8.6 - LabView 2014 ♖♜
    Attachments:
    2013-06-22_2dhistogram 2009.zip ‏61 KB

  • Find the correct data from series of messages

    I have the RFC -> XI -> SOAP scenario; In this scenario, RFC will send some notes of service for the WEB service via SOAP.
    When I access the monitor of messages of the XI, I got series of messages. How I should find the correct messages out of this bunch.
    How can I locate one definitive note for the number of it through the monitor of the XI?

    a s
    You need to use selection criteria to restrict message view to the relevant messages
    Monitor for Processed XML Messages
    http://help.sap.com/saphelp_nw04/helpdata/en/c4/9a5c3bab977239e10000000a114084/frameset.htm
    Once you have identified the relevant messages (say your three examples of the same message type), you then need to distinguish between each one.  To do this you will need to open each relevant message then view the payload of the inbound message and / or the response message.  This blog is only relevant in that it highlights the message header, payload etc.  Refer to left hand side of screen once you have displayed the message version
    Monitoring for Processed XML messages in ABAP Proxy
    Monitoring for Processed XML messages in ABAP Proxy
    Regards,
    Mike

  • How should I correct my code to find the mean, median & mode from an array?

    Hello everyone,
    I have been learning Java for about a month now and am stuck with the following code. There are no highlighted errors on my program when typing it into Eclipse but I get an error message when I try to run my program.
    Here is the code:
    import java.util.Random;
    * <dl>
    * <dt>Purpose:
    * <dd>Example program that randomly generates, collates and outputs numbers.
    * <dt>Description:
    * <dd>This program generates 10000 random numbers between 0 and 99 inclusive.
    * It also keeps count of how many times each number is generated and prints these
    * counts out to the screen in the format of mean, median and mode.
    * </dl> 
    * @author  Woodie Woodpeck
    * @version $Date: 2008/10/27 14:44:00 $
    public class Exercise3Point08
         public static void main(String[] args)
                   int[] counts=new int [100];
                   for(int i=0;i<100;i++)
                        counts=0;
                   Random r=new Random();
                   for(int n=0;n<10000;n++)
                        counts[r.nextInt()%100]++;
                   double sum=0.0;
                   int maxCnt=0;
                   int mode = 0;
                   int runningCount=0;
                   int median = 0;
                   for (int i=0;i<100;i++)
                        sum+=(i*counts[i]);
                        if (counts[i]>maxCnt)
                             mode=i;
                             maxCnt=counts[i];
                        if (runningCount<5000&&(runningCount+counts[i])>=5000)
                             median=i;
                        runningCount+=counts[i];
                   System.out.println("Mean =" + (sum/10000));
                   System.out.println("Median =" + median);
                   System.out.println("Mode =" + mode);
    Here is my error message:Exception in thread "main" java.lang.UnsupportedClassVersionError: Bad version number in .class file
         at java.lang.ClassLoader.defineClass1(Native Method)
         at java.lang.ClassLoader.defineClass(ClassLoader.java:620)
         at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
         at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
         at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
         at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
         at java.security.AccessController.doPrivileged(Native Method)
         at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
         at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:268)
         at java.lang.ClassLoader.loadClass(ClassLoader.java:251)
         at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:319)
    And that's it. Hmmmm. Strange. I hope someone can help.
    Many Thanks
    Wood                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           

    Hi Edward,
    I moved the file from my college computer to my home computer using a USB stick and changed the workspace path on my Eclipse software to match the files that I transferred. I also cleared out a lot of random code that I had lying around my hard-drive before trying to use the code that I pasted above.
    From reading the output I guess there is a problem with the class. Do you think I might have transferred the file from one computer to another incorrectly? Do you know how I can clean and rebuild a project? Eclipse seems quite daunting and awfully complicated for a beginner!
    Thanks
    Wood

  • Can't find the meaning of PRC_STAT_H value in BAPI_SALESORDER_GetStatus

    Hi All,
    Do have any idea where can i find the definition of the values for PRC_STAT_H in BAPI_SALESORDER_GetStatus? When I used the BAPI_SALESORDER_GetStatus it returned the PRC_STAT_H value of A but how do i know what "A" stands for or what are possible values i'll be getting in PRC_STAT_H?
    Thanks in advance.
    Regards,
    myra

    You can find documentation using transaction BAPI
    Field
    PRC_STAT_H
    Overall processing status of document
    Definition
    The processing status of the entire sales document.
    Use
    The system determines the status of the entire sales document by taking into account the status of all header-related information and the status of all individual items. The status message tells you whether processing of the sales document is open, in progress, or complete.

  • How to find the premise GUID to a given premise number in CRM

    Hi Guys,
    I try to find the PremiseGUID (VerbrSt.GUID) to a given Premise Number (Verbrauchsstellen-Nr. in German), either in  IS-U (6.0) or in CRM (2007).
    I need it as a foreign key in CRM table ISU_POD to connect the PoD with the Premise (field is named u201CFF0047u201D or u201CVerbrSt.GUIDu201D  in table ISU_POD).
    I think it should be a 22 dec. alphanum. field, corresponding to the 10 dec. num. field of the premise number.
    Any suggestions in which table(s) I can find the PremiseGUID?
    Thank you very much.
    Christian

    Hi Anji,
                The view VIAUF_AFVC  is for maintenance orders and operations. I tried giving my functional location on the selection screen and checked for the contents , but it says no entries found. Probably this table will get populated only when a maintenance order is issued.
       I need to find out the equipments at a given functional location . Is there any other way ?
    regards,
    Venkatesh.

  • Find the employees in a department having maximum number of emps ?

    Dear All ,
    how to get the employees in a department having maximum number of employees using only one select clause in whole query
    i don't need more than one select statement in whole query.
    Thanks
    Damby

    910346 wrote:
    Dear All ,
    how to get the employees in a department having maximum number of employees using only one select clause in whole query
    Looks like a home work.. What have you tried so far?
    i don't need more than one select statement in whole query.Is there any specific reason for this?
    One possibility is to create a function to get the department id with maximum number of employees. Then use this function to filter out your data..

  • I am measuring mV on 8 channels using 2 NI 9239's and want to find the mean of each channel

    I'm using 2 NI 9239's to capture the voltages at 8 point on a test fixture. The voltages are very small (a few mV). I want to take an average of 1k samples from each channel and use these to calculate the resistivity of the sample under test. 
    What is the easiest method to precisely measure 8 channels?

    Let's start from the beginning.  Do you know how to read 1k samples from 8 channels using a single DAQmx Task?  Once you have that, then use a FOR loop to do a mean on each channel's data.
    There are only two ways to tell somebody thanks: Kudos and Marked Solutions
    Unofficial Forum Rules and Guidelines

  • After installing Lion, many of the sites I go to in Safari fail an the screen message states that Safari "can't find the server."  I've tried a number of suggested solutions but still no luck.

    Has anyone else had this issue and found a resolution?

    Thanks C F McBlob but I recursively changed the permissions of my Music directory meaning every file and directory beneath it, as well as the directory itself, had the write permissions added.
    I used "chmod -R u+w ./Music" and chmod -R g+w ./Music" to do it.
    Alas, no cigar. :-(

  • Finding the total size of a string when number of characters are known.

    Hi: I am having trouble inserting a field in a record that is CLOB. The number of characters in the string is 59298. Any idea how to know what is the size of this string? I am trying to figure out if I am exceeding the size of the string. The error I get is the following
    ORA-06512: at "SYS.DBMS_LOB", line 789
    ORA-06512: at line 1
    Second exception: ORA-21560: argument 2 is null, invalid, or out of range
    ORA-06512: at "SYS.DBMS_LOB", line 789
    Thanks
    Ray

    Either your stacktrace is incomplete or you make something wrong by copy/paste. And please, by providing sql/plsql code, use the tags [ code ] [ / code ] or [ pre ] [ / pre ], otherwise it is very hard to read.
    Here is small demonstration of what i mean by 3rd parameter:
    SQL> CREATE TABLE T_LOB(ID NUMBER,MESSAGE CLOB)
      2  /
    Table created.
    SQL> DECLARE
      2  l_clob CLOB;
      3  BEGIN
      4  INSERT INTO t_lob VALUES(1,'Hello')
      5  RETURNING message INTO l_clob;
      6  dbms_lob.writeappend(l_clob,length(',world'));
      7  END;
      8  /
    dbms_lob.writeappend(l_clob,length(',world'));
    ERROR at line 6:
    ORA-06550: line 6, column 1:
    PLS-00306: wrong number or types of arguments in call to 'WRITEAPPEND'
    ORA-06550: line 6, column 1:
    PL/SQL: Statement ignored
    SQL> DECLARE
      2  l_clob CLOB;
      3  BEGIN
      4  INSERT INTO t_lob VALUES(1,'Hello')
      5  RETURNING message INTO l_clob;
      6  dbms_lob.writeappend(l_clob,length(',world'),',world');
      7  END;
      8  /
    PL/SQL procedure successfully completed.
    SQL> SELECT * FROM t_lob
      2  /
            ID MESSAGE
             1 Hello,worldIn your examples, after length('some lengthy string...' there is no more parameters to dbms_lob.writeappend ( or i don't see any).
    Best regards
    Maxim

  • How to find the moving average for perticular time step for same time series

    Hello everyone,
    I am new in labview and I have one issue. I have a huge text file with the different pressure value of  different ports.
    I make the VI in which first I read the text file and identify the perticular port column. In that column there are 32768 pressure value.
    Time  Num     Port 101 Port 102 Port 103...... Port 532
    0         1
    0.001   2
    50       32768
    And this all reading takes in 50 sec and I have to split this readings in 4.5 sec... in every 4.5 sec there are 2969 values...
    Now please go throw the attched VI... i am able to find the mean value with the 12 time step of 2969 value...
    Now I want to do is, to find again the mean value of 2969 values(2970 to 5938) with time step of 12 and so on until 32768... so it happens 11 times in series...
    So can anyone modify my VI??
    Thank you,
    Solved!
    Go to Solution.
    Attachments:
    Moving average.vi ‏18 KB

    please go through the attched VI
    I made some correction in that.Now I am able to find the mean value for first 2969 rows with the overlapping time step of 12.
    It means I am able to find the mean value from 1-12,2-13,3-14 ... 2958-2969...
    but now the problem starts, I want to calculate the mean value of next 2969 rows which is 2970 to 5938 with the time step of 12...
    So please modify my VI.. I stuck with the serious problem...
    I have 32768 rows and have a partition of 2969 rows so the loop has to be repeat for 11 times.
    hope you understand the prob
    Thank you 
    Attachments:
    Moving average.vi ‏19 KB

Maybe you are looking for