FFT plot of sampled data

I already have sampled data of a input signal in time domain. the signals are sampled via ADC and stored in excel file(around 16K samples). I need to feed it to FFT VI to obtain the FFT plot. I tried multiple FFT VIs but no one accept samples data directly which is stored in 1D array. Any ideas? Thanks.
Solved!
Go to Solution.

In the link below I have posted a FFT example. It is quite old made in Labview 6I but it does all you need. Please take a look at it.
http://forums.ni.com/ni/board/message?board.id=170&thread.id=163587&view=by_date_ascending&page=2
Besides which, my opinion is that Express VIs Carthage must be destroyed deleted
(Sorry no Labview "brag list" so far)

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Plot my sampled data

Hello
I am trying to plot my sampled data but I think I am donig somethinng wrong.
I took 1000 samples pf my analog signal at 1Kz, dt=10, stored it in an array and through fft spectrum.vi I tried to plot the data, Ampliteude vs frequency. The analog input is a magnetic field meter, I was measuring the field of my pc for testing.
The problem I think is the scale of the frequency, my opinion is that the peak had to be in 50Hz and not in 0,05 Hz
I attached snapshots of my program and my results. could you please check it and tell me if i am doing something wrong?
Regards
Solved!
Go to Solution.
Attachments:
snapshots.jpg ‏107 KB

Garbage in, garbage out!
You are lying to LabVIEW so its giving bad data as a result.
If you read the help for the timed loop you will see the dt is in units of the timing source... you are gathering data at 100 Hz.
Next:
"dt" for a waveform should be in seconds so for 100 Hz the dt should be 0.01 NOT "10".
So read the help, mod your code and you should get much more resonable results.
Ben
Ben Rayner
I am currently active on.. MainStream Preppers
Rayner's Ridge is under construction

I'm doing a scan around a line by sampling data 360 degrees for every value of z(z is the position on the line). So, that mean I have a double for-loop where I collect the data. The problem comes when I try to plot the data. How should I do?

I'm doing a scan around a line by sampling data 360 degrees for every value of z(z is the position on the line). So, that mean I have a double for-loop where I collect the data. The problem comes when I try to plot the data. How should I do?

Jonas,
I think what you want is a 3D plot of a cylinder. I have attached an example using a parametric 3D plot.
You will probably want to duplicate the points for the first theta value to close the cylinder. I'm not sure what properties of the graph can be manipulated to make it easier to see.
Bruce
Bruce Ammons
Ammons Engineering
Attachments:
Cylinder_Plot_3D.vi ‏76 KB

Open an audio file and get sampled data

Hello,
there is a way to open an audio file and get an array with sampled data in Java?
I need to perform an fft of my audio file.
Best Regard
Manuel

Dear Mr Thompson,
this is my first post on this topic.
I have already tried various way to get samples from audio file, in particular I focused my attention on this:
http://jvalentino2.tripod.com/dft/index.html
I have implemented the code illustrated in the tutorial but the result is unsatisfactory. If I try to plot the samples of obtained from a pure tone the result is not the expected waveform but something very different, a Fourier analysis of this data is completely useless. Hence I am looking for a way to read data in a similar manner to the matlab's function auread (http://www.mathworks.com/access/helpdesk_r13/help/techdoc/ref/auread.html).
Fft is not really hard to implement but I'm using a scientific library (http://www.ee.ucl.ac.uk/~mflanaga/java/) for obtain values in frequency space.
I apologize for the inaccuracies.
Regards

How to modify the VB examples in ni-scope to sample data simultaneously from two channels in PCI 5922?

Dear all:
I want to write VB programs to sample data simultaneously from two channels in PCI 5922. The niscope driver has some example VB programs to sample data from one channel, for example, the "save to file ", the program works well to sample the data from one channel. When I modify it to sample data simultaneously from two channels, I always get error so I seek your help on how to write the program to sample two channels simulatenously. Thanks. I attached the sample program here and what I tried to modify is the "channel name" and "waveform()"
Regards
Andy
Attachments:
savetofile.doc ‏42 KB

Hi Bajaf, regarding the FFT of the four channels, the next link might be what your looking for:
http://digital.ni.com/public.nsf/allkb/862567530005f09c8625671b00739970
Respect the phase issue how are you doing the acquisition of the signals, are you doing two independent acquisitions? if you are controlling them as independent acquisitions try to synchronize them with triggers and the clock.
How much are they out of phase?
By the way we know have forums in Spanish
Best Regards
Benjamin C
Senior Systems Engineer // CLA // CLED // CTD

I am inputting my guitar tunes(.wav files) and I am trying to do an FFT on this. Wen I do, the FFT signals are very small and are not on the right frequency scale. However I am able to simulate a sine wave and get an accurate FFT plotted as a cluster.

My .wav file has about 8100 samples and has a sample rate of 11050. I pass the samples into FFT. The output I devide by the size of the array(8100??). This I seperate into 'real' and 'polar'. The 'real' I use to plot. My plot has a starting value of '0' on the X axis. My problem is with the other value for the cluster, i.e; To plot this I need 1. 'real' part of the FFT output. 2. the 'x' axis starting value(0) and 3. how do i get this value? I tried deviding the sampling rate by the size of the samples, but
the FFT plot is really wrong. Anybody has an example vi to convert .wav files to FFT? Thanks alot!!!

Mark! Thanks again for the extended answer!!! I have learned alot from that example you gave me. Here is a simple VI which I am trying to plot as an FFT plot. I have also included a 0.5 sec .WAV file. If you have the time, I will appreciate it if you can tell me how to plot the FFT. This vi is very simple. You can open the included .wav file on the included VI, and you will understand why I am unable to plot an FFT. I am doing this to process my music. Appreciate it!!!
Attachments:
fft_test.vi ‏85 KB
guitar.wav ‏8 KB

Time doesn't match sampled data?

Hallo all experts,
I write a LV code which reads data from USB 6211 and saves them with time instants in a text file, but the time instants don't correspond the sampled data. The time values are generated by elapsed time, after build array with the data read from DAQ, they are fed to the write to a text file. The test signal is 10 Hz, but the text file yields 0.2 Hz signal. How could I synchronize them?
Any tips are highly appreciated.
win2

Don't use the "elapsed time" express VI for precision timings. It seems to have limited resolution (internally, it converts a timestamp to DBL).
You can use e.g. the tick count to keep track of the time. See the attached comparison. (still there will always be some subtle differences due to the software timings).
LabVIEW Champion . Do more with less code and in less time .
Attachments:
usb6211_forumMOD.vi ‏42 KB

How to renormalize number of flows in Netflow Sampled data

Hi,
I am working on extrapolation(renormalization) of bytes/packets/flows from randomly sampled (1 out of N packets) collected data. I believe bytes/packets can be renormalized by multiplying bytes/packets value in exported flow record by N.
Now, I am trying to extrapolate number of flows. So far i have not got any information on it. Do you people have any idea on how flows can be renormalized from sampled data ?
Well, at the same time i have some doubts regarding this concept altogether -
1. In packet sampling, we do not know how many flows got dropped. Even router cache will not have entries for dropped flows
2. In flow sampling, router cache will maintain entries of all the flows and there may be some way by which one can know how many actual flows were there. But again there is no way to know values of individual attributes in missed flows like srcip/dstip/srcport/dstport etc.(though they are there in flow cache)
3. In case of sampling (1 out of N packets), we anyway multiply #packets and #bytes with N to arrive at estimate for total packets and bytes. When we multiply by N, it means we have taken into account all those packets as well which were NOT sampled. So, it means all the packets which flowed between source and destination have been accounted for. Then there are no missed flows, isn't it ? And if there do exist some missed flows then multiplication by N to extrapolate number of packets/bytes is not correct.
4. What is the use of count of flows anyways. Number of flows may vary depending upon the configuration such as active timeout etc. So, it does not provide any information about the actual flow between source and destination unlike number of packets and bytes.
Please share your thoughts.
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The simplest way is to call GetTableCellRangeValues with VAL_ENTIRE_TABLE as the range, next summing array elements.
But I don't understand your comment on checksum, so this may not be the more correct method for your actual needs: can you explain what do you mean?
Proud to use LW/CVI from 3.1 on.
My contributions to the Developer Zone Community
If I have helped you, why not giving me a kudos?

For this sample data how to fulfill my requirement ?

For this sample data how to fulfill my requirement ?
with temp as
select 'MON' WEEKDAY,'9-10' TIMING,'I' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'9-10' TIMING,'II' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'9-10' TIMING,'III' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'10-11' TIMING,'I' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'10-11' TIMING,'II' CLASS FROM DUAL UNION
select 'TUE' WEEKDAY,'9-10' TIMING,'I' CLASS FROM DUAL UNION
select 'TUE' WEEKDAY,'9-10' TIMING,'II' CLASS FROM DUAL
select ?? (what will be the query ??)
How can i get output data in this way :
WEEKDAY TIMING CLASS
MON 9-10 I,II,III
MON 10-11 I,II
TUE 9-10 I,II

If in 11g, you can use LISTAGG
with temp as
select 'MON' WEEKDAY,'9-10' TIMING,'I' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'9-10' TIMING,'II' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'9-10' TIMING,'III' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'10-11' TIMING,'I' CLASS FROM DUAL UNION
select 'MON' WEEKDAY,'10-11' TIMING,'II' CLASS FROM DUAL UNION
select 'TUE' WEEKDAY,'9-10' TIMING,'I' CLASS FROM DUAL UNION
select 'TUE' WEEKDAY,'9-10' TIMING,'II' CLASS FROM DUAL
select
WEEKDAY,
TIMING,
LISTAGG(CLASS,',') WITHIN GROUP (order by 1) as class_aggregate
from temp
GROUP by WEEKDAY,TIMING;
WEEKDAY       TIMING     CLASS_AGGREGATE
MON           9-10       I,II,III
MON           10-11      I,II
TUE           9-10       I,IIOther techniques for different versions are also mentioned here :
http://www.oracle-base.com/articles/misc/StringAggregationTechniques.php#listagg

Need help in framing an SQL query - Sample data and output required is mentioned.

Sample data :
ID Region State
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2 b A1
3 c B1
4 d B1
Result should be :
State Region1 Region2
A1 a b
B1 c d

create table #t (id int, region char(1),state char(2))
insert into #t values (1,'a','a1'),(2,'b','a1'),(3,'c','b1'),(4,'d','b1')
select state,
max(case when region in ('a','c') then region end) region1,
max(case when region in ('b','d') then region end) region2
from #t
group by state
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BPC 5 - Best practices - Sample data file for Legal Consolidation

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we are following the steps indicated in the SAP BPC Business Practice: http://help.sap.com/bp_bpcv151/html/bpc.htm
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Hi,
From [https://websmp230.sap-ag.de/sap/bc/bsp/spn/download_basket/download.htm?objid=012002523100012218702007E&action=DL_DIRECT] this address you can obtain .zip file for Best Practice including all scenarios and csv files under misc directory used in these scenarios.
Consolidation Finance Data.txt is in there also..
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AP/PO Sample Data

I have a requirement to develop a PO/AP environment does any have sample data i can to test requisition and PO approval.
Can any send a sample PO/AP so i can with Data loader

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Hope this answers your query, please let me know if you are looking for any specific information.

EPM 11.1.2.2: Load sample data

I have installed EPM 11.1.2.2 and now I'm trying to load the sample data. I could use help locating instructions that will help with this. While earlier versions of epm documentation seemed to have instructions for loading the sample data, I have yet to find it for 11.1.2.2. Perhaps the earlier versions' steps are supposed to work on this version as well. So I read it. It says to initialize the app then in EAS right click on a consol icon where yuo have the option to load data. Unfortunately, I am using EPMA and I saw no option to initialize when I created the app. In addition, EAS doesnt have the console icon and right clicking on the application doesnt do anything. In short, prior documentation hasnt helped so far. I did find the documentation for EPM 11.1.2.2 but I have yet to locate within it the the instructions for loading the sample application and data. Does anyone have any suggestions?

I considered your comment about the app already existing but if this were true, I think the database would exist in EAS but it doesn't.
I've also deleted all applications, even re-installed the essbase components including the database so it would all be fresh, and then tried to create a new one but still no initialization option is available. At this point, I'm assuming there is something wrong with my installation. Any suggestion on how to proceed would be appreciated.
I've noticed that I dont have the create classic application option in my menu, only the transform from classic to epma option. I also can't navigate to http://<machinename>:8300/HyperionPlanning/AppWizard.jsp. When I noticed these things, I did as John suggested in another post and reselected the web server. This didnt make a difference so I redeployed apps AND selected the web server. Still not seeing it in the menu.
Edited by: dirkp:) on Apr 8, 2013 5:45 PM

Navteq sample data

hi,
I have problems during the navteq sampla data import (http://www.oracle.com/technology/software/products/mapviewer/htdocs/navsoft.html). I'm follwing exactly the instructions from the readme file.
Import: Release 10.2.0.1.0 - Production on Thursday, 25 September, 2008 10:35:28
Copyright (c) 2003, 2005, Oracle. All rights reserved.
Connected to: Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
Master table "SYSTEM"."SYS_IMPORT_FULL_01" successfully loaded/unloaded
Starting "SYSTEM"."SYS_IMPORT_FULL_01": system/********@ORCL REMAP_SCHEMA=world_sample:world_sample dumpfile=world_sample.dmp directory=sample_world_data_dir
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
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Edited by: aspie on Sep 25, 2008 11:45 AM

Hi, I followed the instructions from the readme file:
1. Create a work directory on your machine. Change directory to your work
directory and download the world_sample.zip file into it. Unzip the
world_sample.zip file:
C:\> mkdir world_sample
C:\> cd world_sample
C:\world_sample> unzip world_sample.zip
2. In your work directory, open a Sqlplus session and connect as the SYSTEM
user. Create a user for the World Sample data (if you have not previously
done so):
C:\world_sample> sqlplus SYSTEM/password_for_system
SQL> CREATE USER world_sample IDENTIFIED BY world_sample;
SQL> GRANT CONNECT, RESOURCE TO world_sample;
3. This step loads the World Sample data into the specified user, and creates
the metadata required to view the sample data as a Map in MapViewer. Before
you begin, make a note of the full directory path of your work directory,
since you will be prompted for it. You will also be prompted for the user
(created in step 2), and the SYSTEM-user password. This step assumes that
you are already connected as the SYSTEM user, and that you are in your work
directory. To begin, run the load_sample_data.sql script in your Sqlplus
session. Exit the Sqlplus session after the script has successfully
concluded:
SQL> @load_sample_data.sql
          Enter value for directory_name: C:\world_sample
          Enter value for user_name: world_sample
          Password: password_for_system
SQL> exit;
In step 2 I created a user dedicated tablespace. The same problem.
Regards Arnd.

Want to select query based on sample data.

My Oracle Version
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Prod
I am creating inventory valuation report using FIFO method . here sample data .
create table tranx(
TRXTYPE     varchar2(10) ,ITEM_CODE varchar2(10),     RATE number,qty number
insert into tranx values('IN'     ,'14042014',     457.2     ,10);
insert into tranx values('OUT','14042014',     0,          10);
insert into tranx values('IN','14042014',     458.1,     35);
insert into tranx values('OUT','14042014',     0,          11);
insert into tranx values('OUT','14042014',     0,          6);
insert into tranx values('IN','     14042014',     457.2     ,10);
insert into tranx values('OUT','     14042014',     0,          3);
insert into tranx values('OUT','     14042014',     0,          4);
insert into tranx values('IN','     14042014',     457.2,     20);
insert into tranx values('OUT','     14042014',     0,          5);
insert into tranx values('OUT','     14042014',     0,          9);
insert into tranx values('OUT','     14042014',     0,          8);
current output
TRXTYPE     ITEM_CODE     RATE      QTY
IN     14042014     457.2     10
OUT     14042014     0          10
IN     14042014     458.1     35
OUT     14042014     0          11
OUT     14042014     0          6
IN     14042014     457.2     10
OUT     14042014     0          3
OUT     14042014     0          4
IN     14042014     457.2     20
OUT     14042014     0          5
OUT     14042014     0          9
OUT     14042014     0          8above data populate based on first in first out . but out rate is not comes from that query. suppose fist 10 qty are OUT its rate same as IN. but when qty start out from 35 rate will be 458.1 till all 35 qty will not out. like out qty 11,6,3,4,5,9 now total are 38 .
when qty 9 will out the rate are 6 qty rate 458.1 and other 3 out rate of 457.2 means total value of 9 out qty value is 4120.20 .
Now 35 qty is completed and after that rate will continue with 457.2 till 10 qty not completed.
I think you understand my detail if not please tell me .
thanks
i am waiting your reply.

As SomeoneElse mentioned, there is no row order in relational tables, so you can't tell which row is first and which is next unless ORDER BY is used. So I added column SEQ to your table:
SQL> select *
2    from tranx
3 /
TRXTYPE    ITEM_CODE        RATE        QTY        SEQ
IN         14042014        457.2         10          1
OUT        14042014            0         10          2
IN         14042014        458.1         35          3
OUT        14042014            0         11          4
OUT        14042014            0          6          5
IN         14042014        457.2         10          6
OUT        14042014            0          3          7
OUT        14042014            0          4          8
IN         14042014        457.2         20          9
OUT        14042014            0          5         10
OUT        14042014            0          9         11
TRXTYPE    ITEM_CODE        RATE        QTY        SEQ
OUT        14042014            0          8         12
12 rows selected.
SQL> Now it can be solved. Your task requires either hierarchical or recursive solution. Below is recursive solution using MODEL:
with t as (
           select tranx.*,
                   case trxtype
                     when 'IN' then row_number() over(partition by item_code,trxtype order by seq)
                     else 0
                   end rn_in,
                   case trxtype
                     when 'OUT' then row_number() over(partition by item_code,trxtype order by seq)
                     else 0
                   end rn_out,
                   count(case trxtype when 'OUT' then 1 end) over(partition by item_code) cnt_out
             from tranx
select trxtype,
        item_code,
        rate,
        qty
from t
model
    partition by(item_code)
    dimension by(rn_in,rn_out)
    measures(trxtype,rate,qty,qty qty_remainder,cnt_out,1 current_in,seq)
    rules iterate(10) until(iteration_number + 1 = cnt_out[0,1])
     rate[0,iteration_number + 1]          = rate[current_in[1,0],0],
     qty_remainder[0,iteration_number + 1] = case sign(qty_remainder[0,cv() - 1])
                                               when 1 then qty_remainder[0,cv() - 1] - qty[0,cv()]
                                               else qty[current_in[1,0],0] - qty[0,cv()] + nvl(qty_remainder[0,cv() - 1],0)
                                             end,
     current_in[1,0]                       = case sign(qty_remainder[0,iteration_number + 1])
                                               when 1 then current_in[1,0]
                                               else current_in[1,0] + 1
                                             end
order by seq
TRXTYPE    ITEM_CODE        RATE        QTY
IN         14042014        457.2         10
OUT        14042014        457.2         10
IN         14042014        458.1         35
OUT        14042014        458.1         11
OUT        14042014        458.1          6
IN         14042014        457.2         10
OUT        14042014        458.1          3
OUT        14042014        458.1          4
IN         14042014        457.2         20
OUT        14042014        458.1          5
OUT        14042014        458.1          9
TRXTYPE    ITEM_CODE        RATE        QTY
OUT        14042014        457.2          8
12 rows selected.
SQL> SY.

FFT plot of sampled data

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