unwrap phase 7.1

[gaertner.marco]

Hello all,

I am using Labview 7.1 and want du plot an angle. How can i unwrap the phase? I want to plot it everytime between 0 and 360.

Thank you

[PhillipBrooks]

If you have the Full or Professional version, you can use... "Unrwap Phase". It's in the palette shown below.
(Signal Processing -> Analyze -> Functions -> Time Domain)

For help, see http://zone.ni.com/reference/en-XX/help/lv/71/lvanls/Unwrap_Phase/



If you don't have Full or Pro, then you can write your own implementation. See this NI forum post:

http://forums.ni.com/ni/board/message?board.id=170&message.id=80017&query.id=204150#M80017

Message Edited by Phillip Brooks on 05-24-2007 06:27 AM

[gaertner.marco]

Thank you for your reply. But i cant use the Unwrap Phase tool. If i want to insert it in my VI a dialog appear and say: "You cannott use UnwrapPhase.vi recursively"

What does it means?

[altenbach]

A recursive use occurs for example if you try to place a VI on it's own diagram This should not happen in this case. Can you show us what you are doing?

Still "unwrap phase" is not suitable for your purpose because it won't keep the angle between 0 and 360. It is actually dong exactly the opposite!

If you want to keep the angle between 0 and 360, "divide" the current angle by 360 using quotient&Remainder and keep only the remainder.

[altenbach]

OK, here's an example of an angle ramp between ~0..500. Using quotient&remainder will keep the angle between 0 and 359, 360 will go back to 0,  361 will go back to 1, and so on. Exactly what you need!

The unwrap phase tool will reconstuct the original ramp, removing the discontinuity near 360. The opposite of what you need!

Message Edited by altenbach on 05-26-2007 11:44 PM

[gaertner.marco]

ok, thank you much. But how can i read in my data from a file? The File have to rows: a time channel and a data channel.

i want to read in the unwraped data, process it and store the data in an other file.

[altenbach]

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@gaertner.marco wrote:

ok, thank you much. But how can i read in my data from a file? The File have to rows: a time channel and a data channel.

i want to read in the unwraped data, process it and store the data in an other file.

---

Well, now that we solved the phase problem you come with a seemingly unrelated question about reading data from a file. In principle, that would deserve a new thread.

Your question is way too generic to be answered like that, but "read from spreadsheet file" might work if that's all there is in your file and both rows are simple numbers. However, if there are e.g. headers, things get more complicated. Can you give an example of your file? How is the time formatted? Is the data column just your unwrapped "angle"? How are the values separated (comma, tab, etc.)?

Just read your file, "wrap" the phase angle, and write the data to a new file.