DAQexpress - get delta phase

[eitanthti57]

Hi,

I'm using the USB-6216 device, I connected the AI0 and AI1 to a signal generator and I want to measure the phase shift between these two signals.

Thanks 🙂

[Bob_Schor]

What do you know about Signal Analysis?  What do you know about the properties of the signals you are trying to compare?  Are there multiple frequencies in each signal?  If you plotted each signal separately on a graph, do you expect to be able to determine a unique phase lag by visually sliding the two plots past each other?

Bob Schor

[eitanthti57]

These signals are produced by a signal generator. 

I'm aware of the fact that I can either see the phase shift on graphs(pic 1) or calculate it from the exported CVS file. However, I would like to achieve the same goal in a more automated way - the same as can be done using an oscilloscope. 

Thank you.

[Bob_Schor]

---

@eitanthti57 wrote:

These signals are produced by a signal generator. 

I'm aware of the fact that I can either see the phase shift on graphs(pic 1) or calculate it from the exported CVS file. However, I would like to achieve the same goal in a more automated way - the same as can be done using an oscilloscope. 

---

Ah, you must mean the new "digital" oscilloscopes that do all of the "thinking" for you, can "tell" you the "phase" of a nice, pretty sinusoid, and might even be able to subtract two phase numbers from Channels 1 and 2 and give you a phase difference.

When you study Electrical Engineering, you learn about Signals (the course is often called Signal Theory).  If you then learn how to acquire Signals digitally, you will be able to understand the underlying mathematics that enable your fancy oscilloscope to estimate the Phase of your signal (assuming a low-noise sinusoid), and you'll be able to use whatever Programming Language (e.g. LabVIEW) to make the same measurements and get "phase".

Go talk to a sophomore (I'm guessing here) EE undergraduate student, explain your problem, and ask for help.  Then, knowing what you need to do, use the appropriate LabVIEW tools to do it.  Knowing "the answer" without understanding "the question" would be a disservice to your education.

Bob Schor

[eitanthti57]

You're talking to an Engineer, and I'm quite aware of how scopes work and how to calculate the things I need. 

The aim of my question was to inquire about the features of the software(DAQExpress/VI).

Do you know how can I apply these measurements (the same as I can get PK-PK values from this tool)?

Let's be efficient:)

Thank you.

[RavensFan]

Did you dig through the signal processing palettes?

Signal Processing >> Waveform Measure >>  Extract Single Tone  will give you the phase of the signal.

[eitanthti57]

Hi,

Its looks different at my tool, There isn't a "Waveform Measure" with a phase detection:

Thanks.

[eitanthti57]

I am using DAQExpress

[RavensFan]

I'm not familiar with DAQExpress.

I'm sorry, but the time I had gotten to your last message, I had lost track that you were using NXG which is something I haven't touched yet.

I would expect there is a function in there to calculate phase and you might have to dig deeper to find it.  It's also possible that NI hasn't incorporated that yet.

[eitanthti57]

Thanks