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

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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
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Best regards,
Philip C.
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- Philip Courtois, Thinkbot Solutions
Attachments:
PSD.JPG ‏139 KB

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.
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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
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Attachments:
lock-in testmod.vi ‏36 KB

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Hello,
If I understand your application correctly, you are generating a Gaussian white noise signal which you output to a speaker. You have a process running in parallel that inputs two sound signals and then analyzes these input signals. If I have misunderstood you, then please correct me.
From your explanation I am not clear on the exact problem. Is the problem that you are seeing a small pause in the output signal, which you believe may be attributed to the processing that you are doing on the inputs? Or, is the problem that the noise output signal seems to repeat itself once every two seconds or so?
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Tone measurement express vi affect the output signal?

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