Tone measurements Express VI

I had installed the Sound and Vibration toolkit . When I open Tone Measurements from Tone and Distortion of Sound and Vibration,It can't initializing completely and close automatically . So I can' t configure it , please help to solve this problem,thanks!

Hi,
I had done with your proposal.Both of them is 2012,it's OK now.Thank you! New problem appeared,I acquired signal to analysis THD and at the same time I used "Harmonic Distrotion Analyzer.vi".The two values are different.Please see attached picture.
Attachments:
THD test capture.jpg ‏60 KB

Similar Messages

Tone measurement express vi affect the output signal?

Hi everyone, I am doing a oscilloscope to measure the input signal coming from my analog input of myRIO. I am still new to Labview and I not sure how to implement the tone measurement to measure my signal frequency, amplitude and phase. The first diagram below show the program before i haven't add the tone measurement express vi, the signal get from the waveform graph seem great. However, when i added the tone measurement express vi, the signal seem distorted and unstable. Does anyone know how to solve this problem? Is it the way I implemented is wrong?
Figure 1: without tone measurement express vi
Figure 2: with tone measurement express vi

I would like you to prove the "bug" that you're describing by creating an example that shows the calculated and the expected results. By opening the code of the "Spectral Measurements" Express VI you can dig into the heart of the calculation, and there (in the "ma_FFT Power Spectrum and PS Density no State.vi") you will see that the Power Spectral Density indeed IS calculated by using the formula PSD = (Power Spectrum/(df*Noise Power BW of Window)). See the attached PSD.jpg that shows where the calculation happens.
The Power Spectral Density is supposed to be dependant of the chosen Window. Please read chapter 5 "Smoothing Windows" in the "La
bVIEW Analysis Consepts" manual.
Best regards,
Philip C.
National Instruments
- Philip Courtois, Thinkbot Solutions
Attachments:
PSD.JPG ‏139 KB

FFT and Tone Measurements

Does the Express VI, Spectral Measurements and the Extract Multiple Tone Information VI return the same data? The express VI displays the information in dB and the Extract Multiple Tone Information VI returns the amplitude in volts. The issue is that the amplitude don't seem to match. I am using 20log(volts) to convert to dB. The chart shows about -14 dB and the Extract Multiple Tone Information VI returns -27 dB (volts convert to dB).
Any help is appreciated,
Matthew Fitzsimons
Certified LabVIEW Architect
LabVIEW 6.1 ... 2013, LVOOP, GOOP, TestStand, DAQ, and Vison

You are calculating a power spectal density in the spectral measurements Express VI. If you configure it to calculate the spectral measurement magnitude (peak) the values will match. The difference from the help file is:
Magnitude (peak)—Measures the spectrum and displays the
results in terms of peak amplitude. You typically use this measurement with more
advanced measurements that require magnitude and phase information. The
magnitude of the spectrum is measured in peak values. For example, a sine tone
of amplitude A yields a magnitude spectral value of A at the sine tone
frequency. You can unwrap the phase spectrum or convert it from radians to
degrees by setting Phase to Unwrap phase or
Convert to degree, respectively. If you place a checkmark in
the Averaging checkbox, the phase of the spectrum is zero for
averaging.
Power spectral density—Measures the spectrum and displays
the results in terms of power spectral density (PSD). Power spectral
density is a scaled version of Power spectrum, where
the power present within each spectral bin is normalized by the frequency bin
width. You typically use this measurement to examine the noise floor of a signal
or the power in a specific frequency range. Normalizing the power spectrum by
the bin width makes this measurement independent of the signal duration, or
number of samples.So, they are the same if they are the same.
Hope that this helps,
Bob Young
Bob Young - Test Engineer - Lapsed Certified LabVIEW Developer
DISTek Integration, Inc. - NI Alliance Member
mailto:[email protected]

Phase measured by two tone measurement have different dt

Dear all;
I write a labview program for isolated a signal from the mixture of two signals by using a reference input. I choose to use butterworth filter and apply it in bandpass mode. To determine the band width of the filter, I also use two tone measurement vi to detect the phase of the reference signal and the signal I want to outcome. Unfortunately, when I run my program, warming with message "waveforms have different dt value" is always show. How can I fix this problem?
Regards
Attachments:
lock-in test.vi ‏88 KB

Well you got a bad case of the DDT's and dt's
If you get rid of those express vis and use a vi from the waveform measurments pallette you won't get fooled by that dt that does not exist coming out of your filter
Of course you COULD use the Digital IIR Filter vi off the Waveform conditioning palatte and keep your dt info but that doesnt get rid of your DDT's
Here is one quick mod
Jeff
Attachments:
lock-in testmod.vi ‏36 KB

Bug within Write to Measurement Express vi

I think I have found a Bug within the Write to Measurement express VI.   I have attached an example VI to help reproduce the error.
Here is a bit of history.. I have a data monitoring system which runs continuously. I have the write to measurement setup to create a new file every 12 hours. What I noticed is that even though a new file has been created, I still cannot access the old files until I stop the VI that has the Write to Measurement VI in it. I am trying to access the files via Diadem.
For this application, it is not practical to stop the Data Monitoring Main VI every time I need to look at the data.  The alternative that I found was to not use the Write to measurement express VI and use open/write/close TDMS vi's.   This is not an acceptable solution as the features programmed into the Write to measurement Express VI are need for my application.
Can someone please fix this or help me fix it?
Thank you
Mike
Attachments:
example code.vi ‏77 KB

Hello Mic,
Please understand that I can suggest a workaround, and I've tested it in your scenario and it seems to work OK, but I cannot guarantee this workaround for all possible use cases of this Express VI. It is for this reason that we generally don't like to recommend one-off modifications to VIs that ship with LabVIEW - they do not get tested with as wide a set of use cases as we do on VIs when we ship them. As such, I'm not going to just hand you a VI to replace in vi.lib, but I will show you a few edits you can make to work around this issue.
Open this VI: "[LabVIEW Install Dir]\vi.lib\express\express shared\ex_TDMS\ex_createorOpenTDMS.vi"
Open its diagram. Near the left there's a section that looks like this:
The current known bug is with the "Not A Number/Path/Refnum?" function on TDMS files, so you'll see the following changes in the below diagram, which hopefully you can make and try out in your use case. I would highly recommend making a backup copy of this VI before saving any changes!
Delete the "Not A Number/Path/Refnum?" function.
Connect the "new file?" input to a "Not" function, and wire the output of the "Not" to the case structure selector where "Not A Number/Path/Refnum?" was previously being used.
Delete the wire connecting the error out of the first inner case structure to the second inner case structure, and re-route the error wire around the first case structure.
Hopefully with these three instructions and comparing the shipping and workaround images you can successfully get up and running.
Message Edited by Jeff B on 03-01-2007 08:12 AM
Attachments:
shipping.gif ‏5 KB
workaround.gif ‏6 KB

What's the unit label of y-axis of PSD when using Spectral Measurement Express VI?

Hi:
What's the unit label of y-axis of PSD when using Spectral Measurement Express VI?
Selected Measurement : Power spectral density
Result : dB
No Averaging..
Is dB/Hz the magnitude label of PSD output? Thx!

There could be an issue the the Express VI converting your waveform data into the dreaded Dynamic Data Type, which is just causing more and more memory to be used.
So what I would recommend is use the DAQmx Configure Logging VI to configure DAQmx to stream the data as you read straight to a TDMS file. There are various other properties you can set to make the logging go across files. You just set up the logging before running your task.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

How does the window selected on the spectral measurements express vi affect the output?

I'm using the spectral measurements express vi to find the power spectral density of a fairly broadband signal. I've already discovered a bug in the express vi; it doesn't divide the power spectrum by the equivalent noise bandwith for the window as it should. However, even after taking this into account by using the scaled time window vi to divide this factor out, the PSD is still changing with the window. How can I get the PSD to be constant with varying windows??

I would like you to prove the "bug" that you're describing by creating an example that shows the calculated and the expected results. By opening the code of the "Spectral Measurements" Express VI you can dig into the heart of the calculation, and there (in the "ma_FFT Power Spectrum and PS Density no State.vi") you will see that the Power Spectral Density indeed IS calculated by using the formula PSD = (Power Spectrum/(df*Noise Power BW of Window)). See the attached PSD.jpg that shows where the calculation happens.
The Power Spectral Density is supposed to be dependant of the chosen Window. Please read chapter 5 "Smoothing Windows" in the "La
bVIEW Analysis Consepts" manual.
Best regards,
Philip C.
National Instruments
- Philip Courtois, Thinkbot Solutions
Attachments:
PSD.JPG ‏139 KB

Implementation of tone measurement vi in speedy33 project

i am using labview 8.2 i have speedy33 processor. tone measurement vi is available in labview8.2. but when creating a project with speedy33 the tone measuremet vi is not available.i plan'd to import tone measurement vi from normal labview8.2 to project in speedy33.. but it di'nt work out... pls tell me how to implement tone measurement vi in speedy33...
Solved!
Go to Solution.

I am sending you a VI which identifies which tone is present in the signal acquired through the speedy 33 microphone.The identification is done by frequency comparison based on the concept of DTMF.
Include this VI in a Speedy 33 project.
First, carry out the testing of the sample stored in your system with this VI. The results you receive will be characteristics of your sample.
Based on these results, you can reconfigure this VI to process the input signal acquired from speedy 33 so as to search for the presence of the desired characteristics.
Hence you can identify whether the required sample is present in the acquired signal.
Regards
Akshat Jain
Attachments:
DTMF Decoder.vi ‏32 KB

Configuring the reference power (dB) in the Spectral Measurement express VI

What is the reference power (dB) or pressure in obtaining the dB FFT response from the Spectral Measurement express VI? We need to obtain the SPL of a cellphone speaker and SPL is measured when the reference pressure/power is 20uPa or 1pW.... The data result is in negative dB but we need to have a positive result. Im thinking that maybe the reference is at 1mW..

You can convert Express VIs to regular subVIs. Then open the block diagram and look at what they have done.
In this case when you get six levels down into subVIs you find one called ma_Convert to dB.vi. It has inputs for dB reference for ch X and ch Y. The default values are 1.00. These inputs are not wired in the SubVIs of the Express VI.
To change the reference FIRST Make a Copy if the converted Express VI with a new name. Put it into your project, not in vi.lib. Similarly, make copies with new names of any subVIs you need to change. Then make the changes you need on these copies. Document those changes so anyone looking at the code knows why the standard Express VI was not used and what the differences are. Put the changed VI in your main VI and get the SPL values.
Lynn

Amplitude measurement using "Tone Measurement" when monitoring amplitude of a waveform

Exactly how does Labview make the amplitude measurement using "Tone Measurement" when monitoring amplitude of a waveform?
What is the mathematical operation that Labview uses to make an amplitude measurement when using "Tone Measurement" function?
Thank you!
OpResp

Hello,
Yes we have a very detailed tutorial on how the method of signal analysis in LabVIEW, please take a look at the following document.
The Fundamentals of FFT-Based Signal Analysis and Measurement in LabVIEW and LabWindows/CVI
http://zone.ni.com/devzone/cda/tut/p/id/4278
I hope you find it informative!
Regards,
Anna K.
National Instruments

Waveform measurements - info needed

I am fairly new to LabView and am trying to understand some of the vis in the Waveform Measurements and Analyze folders. Help with any of the following questions is appreciated.
1) What is the phase output of the Spectral Measurements Express vi? I've seen several examples using this function and none of them use the phase output. If I put in a simulated sine wave with no phase offset, the FFT phase output is -90 deg at the input freq.
2) What is the amplitude output of the Tone Measurements Express vi? It looks like average peak value over the duration of the signal, but I'd like to be sure.
3) If I get a value of 28.42f at the "detected phase" output of the Extract Single Tone Information vi, what does the "f" mean?
4) Is there any information about the details of these functions? The information in the Help window is scant, the tutorials provide a lot of theory, the examples don't always cover what I want to know. Is there somewhere that provides a fuller explanation of the inputs and outputs of the functions?
Thanks in advance,
Margaret

Hi Margaret,
In response to question 1, the Spectral Measurements Express VI is used for FFT-based measurements, and the Tone Measurements VI is used to find the frequency or amplitude of a specific signal. Have you tried viewing the Detailed Help for these commands? These can be viewed by right-clicking on the command, choosing Control-H to bring up the Context Help, and clicking Detailed Help. This will allow you to view Examples and detailed information on the inputs and outputs.
Here is some detailed information about the Spectral Measurements Express VI from the Help:
FFT-based spectral computations assume that the finite block of
signal data represents one period of a periodic signal. The computed spectrum of
this effective periodically extended signal shows energy spreading into
frequencies that were not present in the original signal. To reduce this
spectral leakage, use smoothing windows to taper the sharp transitions in the
effective signal. You do not typically use windows if you can acquire an integer
number of cycles of each frequency component measured or if you are analyzing
noise spectra.
In response to question 2, the amplitude of the Tone Measurements Express VI returns the amplitude of the detected single tone in Volts peak (Vp).In response to question 3, what is the phase of the signal that you're measuring? I used this VI with a Simulate Signal VI and simulated a sine wave and was able to correctly use the Extract Tone VI for all phases. Have you tried doing this?
Also, here is the manual for the Spectral Measurements Toolkit. Let me know if you have any more questions.
Amanda Howard
Americas Services and Support Recruiting Manager
National Instruments

Signal vs frequency measuremnt

Hi,
I am aquiring signal from DAQ board from three channel (Ch0, Ch1,Ch2). I want to measure the frequency of the Ch0 signal and plot it vs Ch1/Ch2 signal. I am sweeping the frequency in the channel 0 from 25kHz to 100KHz. I am using Labview s default 'tone measurement express vi' to extract frequncy of the Ch1 and feeding it as an X input in a XY plot. My Y input is a formula relating to the voltage of CH1 and CH2. But I am getting a moving point rather than a contineous plot in my XY plot. Can anyone help me. I have attached my vi.
Thanks,
prem
Attachments:
Frequency Domain DSR Measurement.vi ‏357 KB

Hi jibon,
Welcome to the LabVIEW forums!
I don't have the hardware you're using, so I cannot run the example VI you've provided, but it appears that you're using an XY graph inside a while loop- this means that the graph will be overwritten each loop. To preserve the previous data points, you'll need to use a memory structure of some type.
The simplest way to do this is with the Collector express VI (found in the Express>>Signal Manipulation palette) , but you might also want to try a shift register with a build array function:
This KnowledgeBase article and the examples it references might also be helpful- it has a few links to code that demonstrates using an XY Graph with a history:
KnowledgeBase 4TCFBDW8: How Do I Make an XY Graph Behave as an XY Chart?
http://digital.ni.com/public.nsf/allkb/18B56D8556D44BF18625753D006EFF7C
Hope that helps!
Regards,
Tom L.

Simulate frequency

I need to simulate two different sets of frequencies, 9544hz and 6362hz and display this 2 sets of frequencies side by side as square waves on a waveform graph with a period of 55.55ms. Is anyone able to help?

1st , it is more accurate to use the Tone measurements Express VI
than the timing ans transition Express VI. Find the attached file
you can change the Plot Color, Name, viewing wither programatically or manually
for
manually configuring the Plot(s) behaviour , scale the Plot Legend as
seen inside the Red Circle, so you will find the available plots on the
graph or chart indicator
for changing color and appearance , click on the icon inside the
Blue circle as shown below and choose the properties you want to edit.
Best Regards
Message Edited by MAshraf on 12-17-2008 03:37 AM
Eng. Mohammed Ashraf
Certified LabVIEW Associated Developer
InnoVision Systems Founder, RF Test Development Engineer
www.ivsystems-eg.com
Attachments:
plot.JPG ‏81 KB
task1-1_Modified.vi ‏134 KB

Request better support skin tone evaluation/measurement

Hello. I am writing this with the intention that it will be read by the folks at Adobe that are involved in the development of Lightroom. I'm pretty new to this forum, however, and I'm a little confused about whether this feature requests thread actually goes to the Adobe Lightroom team, considering that it is in a user-to-user forum. If there is a better avenue to get my feature request to Adobe, I would appreciate if someone could point me in the right direction.
Before I get into my request, I also want to mention that I did my due diligence and searched this thread to make sure this has not been requested before.
I am submitting this request because I do not see any useful way to measure or evaluate skin tone in Lightroom while adjusting white balance (or after adjusting white balance, for that matter). I can do a mouse-over to read RGB values, but I am not aware of any useful way to use RGB values for evaluating skin tones.
I just watched the latest George Jardine video, in which he recommends to use a calibrated monitor and move the Develop controls back and forth until your eye tells you it's correctly adjusted. I enjoyed this video, and I have found that this generally works well for me for tone balance, but I believe an additional tool for measuring or evaluating skin tones would benefit the Lightroom workflow as I will explain below.
I believe that many serious photographers, pro and amateur alike, routinely use the eyedropper in Photoshop for reading CMYK values to confirm the skin tones in their work. Even if they feel like they can usually eyeball pretty well, they find they get greater consistency when they use the eyedropper.
Now I'm not saying that Lightroom necessarily needs CMYK support. Photoshop Elements, for example has a skin tone adjustment even though it doesn't have CMYK support. And I'm also not suggesting that Lightroom necessarily needs skin tone sliders like Photoshop Elements. I'm just suggesting that the Lightroom workflow would benefit from some kind of tool for evaluating skin tone while or after adjustments are being made in the Develop Module. I would like to leave it up to Lightroom to decide exactly how to implement this.
The only way I currently see to do adjust while measuring skin tones is to open the file in Photoshop, make adjustments, and save. Even if there is a way to do this with ACR and have the adjustments saved in the sidecar or in the DNG, it still seems like a time-comsuming and unnecessary step for my workflow.
Now this request is predicated on the assumption that evaluting skin tone is fundamental enough for a basic workflow that it should be included in Lightroom. In my opinion it is, and that is why I am making this feature request. I'm sure that some might not need it for their workflow, but it seems to me that this would be a valuable feature to a great many Lightroom users.
Thanks for lending your ear, Adobe. I look forward to ALL your future versions of Lightroom, and I hope that skin tone evaluation/measurement is included in one of them.
Regards,
Mike

Your post seems to assume that Lightroom is a tool for travel/landscape photography, and other types of photography (e.g., portrait/fashion) should be supported by a "specialized add-on module". I have to disagree with you on that point. Considering many of the examples on the Lightroom marketing are fashion shoots, I would think that they considers portrait/fashion photographers to be an important part of their target audience. They are not a fringe group of specialists.
I'm sure that portrait/fashion photographers would feel the same way about a Lightroom capability that primarily benefits the workflow of a travel/landscape photographer, i.e., when I do do some landscape work, I just edit in Photoshop. But you wouldn't agree to that, would you?
Skin tone measurement can be an incredibly easy tool to implement. It can be something as simple as showing the CMY values alongside the RGB values during a mouseover. Keep in mind, I'm talking about CMY not CMYK, so there should be no need to worry about what ICC profile to use. RGB to CMY is a straightforward transformation. It's embarassingly simple.
There are other ways Adobe can implement skin tone management that would be more powerful but a little more complicated. Those would be great too.
Anyway, thanks for the link to the Adobe feature request page! I will use it.
Regards,
Mike

Write to measurement file Express VI - TDMS file has separate "channels" for each data point

Im trying to write a VI to measure and record thermocouple data from an Advantech T/C DAQ. Using the "DAQNavi" express VI provided by them, connected to the Write to Measurement File express VI, I have managed to read in the data and create a TDMS file. However, when I open the TDMS file, each time step of temperature data is entered as a separate channel, instead of all of the channel data going into one tab. Obviously this is a huge problem as it creates hundreds of tabs after just a few seconds. Any thoughts as to what causes this?

Hi glibby,
How did you configure the Write to Measurement Express VI? Please select "one header only".
If you have your own timestamps to write, please merge your timestamp channel and measurement channels with "Merge Signals" before passing them to the Write to Measurement.
Best Regards,
Mavis

Tone measurements Express VI

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